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Anatomy_Gray_200 | Anatomy_Gray | Each spinal nerve divides, as it emerges from an intervertebral foramen, into two major branches: a small posterior ramus and a much larger anterior ramus (Fig. 2.61): The posterior rami innervate only intrinsic back muscles (the epaxial muscles) and an associated narrow strip of skin on the back. The anterior rami innervate most other skeletal muscles (the hypaxial muscles) of the body, including those of the limbs and trunk, and most remaining areas of the skin, except for certain regions of the head. Near the point of division into anterior and posterior rami, each spinal nerve gives rise to two to four small recurrent meningeal (sinuvertebral) nerves (see Fig. 2.59). These nerves reenter the intervertebral foramen to supply dura, ligaments, intervertebral discs, and blood vessels. All major somatic plexuses (cervical, brachial, lumbar, and sacral) are formed by anterior rami. | Anatomy_Gray. Each spinal nerve divides, as it emerges from an intervertebral foramen, into two major branches: a small posterior ramus and a much larger anterior ramus (Fig. 2.61): The posterior rami innervate only intrinsic back muscles (the epaxial muscles) and an associated narrow strip of skin on the back. The anterior rami innervate most other skeletal muscles (the hypaxial muscles) of the body, including those of the limbs and trunk, and most remaining areas of the skin, except for certain regions of the head. Near the point of division into anterior and posterior rami, each spinal nerve gives rise to two to four small recurrent meningeal (sinuvertebral) nerves (see Fig. 2.59). These nerves reenter the intervertebral foramen to supply dura, ligaments, intervertebral discs, and blood vessels. All major somatic plexuses (cervical, brachial, lumbar, and sacral) are formed by anterior rami. |
Anatomy_Gray_201 | Anatomy_Gray | All major somatic plexuses (cervical, brachial, lumbar, and sacral) are formed by anterior rami. Because the spinal cord is much shorter than the vertebral column, the roots of spinal nerves become longer and pass more obliquely from the cervical to coccygeal regions of the vertebral canal (Fig. 2.62). In adults, the spinal cord terminates at a level approximately between vertebrae LI and LII, but this can range between vertebra TXII and the disc between vertebrae LII and LIII. Consequently, posterior and anterior roots forming spinal nerves emerging between vertebrae in the lower regions of the vertebral column are connected to the spinal cord at higher vertebral levels. Below the end of the spinal cord, the posterior and anterior roots of lumbar, sacral, and coccygeal nerves pass inferiorly to reach their exit points from the vertebral canal. This terminal cluster of roots is the cauda equina. Nomenclature of spinal nerves | Anatomy_Gray. All major somatic plexuses (cervical, brachial, lumbar, and sacral) are formed by anterior rami. Because the spinal cord is much shorter than the vertebral column, the roots of spinal nerves become longer and pass more obliquely from the cervical to coccygeal regions of the vertebral canal (Fig. 2.62). In adults, the spinal cord terminates at a level approximately between vertebrae LI and LII, but this can range between vertebra TXII and the disc between vertebrae LII and LIII. Consequently, posterior and anterior roots forming spinal nerves emerging between vertebrae in the lower regions of the vertebral column are connected to the spinal cord at higher vertebral levels. Below the end of the spinal cord, the posterior and anterior roots of lumbar, sacral, and coccygeal nerves pass inferiorly to reach their exit points from the vertebral canal. This terminal cluster of roots is the cauda equina. Nomenclature of spinal nerves |
Anatomy_Gray_202 | Anatomy_Gray | Nomenclature of spinal nerves There are approximately 31 pairs of spinal nerves (Fig. 2.62), named according to their position with respect to associated vertebrae: eight cervical nerves—C1 to C8, twelve thoracic nerves—T1 to T12, five lumbar nerves—L1 to L5, five sacral nerves—S1 to S5, one coccygeal nerve—Co. The first cervical nerve (C1) emerges from the vertebral canal between the skull and vertebra CI (Fig. 2.63). Therefore cervical nerves C2 to C7 also emerge from the vertebral canal above their respective vertebrae. Because there are only seven cervical vertebrae, C8 emerges between vertebrae CVII and TI. As a consequence, all remaining spinal nerves, beginning with T1, emerge from the vertebral canal below their respective vertebrae. | Anatomy_Gray. Nomenclature of spinal nerves There are approximately 31 pairs of spinal nerves (Fig. 2.62), named according to their position with respect to associated vertebrae: eight cervical nerves—C1 to C8, twelve thoracic nerves—T1 to T12, five lumbar nerves—L1 to L5, five sacral nerves—S1 to S5, one coccygeal nerve—Co. The first cervical nerve (C1) emerges from the vertebral canal between the skull and vertebra CI (Fig. 2.63). Therefore cervical nerves C2 to C7 also emerge from the vertebral canal above their respective vertebrae. Because there are only seven cervical vertebrae, C8 emerges between vertebrae CVII and TI. As a consequence, all remaining spinal nerves, beginning with T1, emerge from the vertebral canal below their respective vertebrae. |
Anatomy_Gray_203 | Anatomy_Gray | Surface features of the back are used to locate muscle groups for testing peripheral nerves, to determine regions of the vertebral column, and to estimate the approximate position of the inferior end of the spinal cord. They are also used to locate organs that occur posteriorly in the thorax and abdomen. Absence of lateral curvatures When viewed from behind, the normal vertebral column has no lateral curvatures. The vertical skin furrow between muscle masses on either side of the midline is straight (Fig. 2.64). in the sagittal plane When viewed from the side, the normal vertebral column has primary curvatures in the thoracic and sacral/coccygeal regions and secondary curvatures in the cervical and lumbar regions (Fig. 2.65). The primary curvatures are concave anteriorly. The secondary curvatures are concave posteriorly. | Anatomy_Gray. Surface features of the back are used to locate muscle groups for testing peripheral nerves, to determine regions of the vertebral column, and to estimate the approximate position of the inferior end of the spinal cord. They are also used to locate organs that occur posteriorly in the thorax and abdomen. Absence of lateral curvatures When viewed from behind, the normal vertebral column has no lateral curvatures. The vertical skin furrow between muscle masses on either side of the midline is straight (Fig. 2.64). in the sagittal plane When viewed from the side, the normal vertebral column has primary curvatures in the thoracic and sacral/coccygeal regions and secondary curvatures in the cervical and lumbar regions (Fig. 2.65). The primary curvatures are concave anteriorly. The secondary curvatures are concave posteriorly. |
Anatomy_Gray_204 | Anatomy_Gray | A number of readily palpable bony features provide useful landmarks for defining muscles and for locating structures associated with the vertebral column. Among these features are the external occipital protuberance, the scapula, and the iliac crest (Fig. 2.66). The external occipital protuberance is palpable in the midline at the back of the head just superior to the hairline. The spine, medial border, and inferior angle of the scapula are often visible and are easily palpable. The iliac crest is palpable along its entire length, from the anterior superior iliac spine at the lower lateral margin of the anterior abdominal wall to the posterior superior iliac spine near the base of the back. The position of the posterior superior iliac spine is often visible as a “sacral dimple” just lateral to the midline. How to identify specific vertebral | Anatomy_Gray. A number of readily palpable bony features provide useful landmarks for defining muscles and for locating structures associated with the vertebral column. Among these features are the external occipital protuberance, the scapula, and the iliac crest (Fig. 2.66). The external occipital protuberance is palpable in the midline at the back of the head just superior to the hairline. The spine, medial border, and inferior angle of the scapula are often visible and are easily palpable. The iliac crest is palpable along its entire length, from the anterior superior iliac spine at the lower lateral margin of the anterior abdominal wall to the posterior superior iliac spine near the base of the back. The position of the posterior superior iliac spine is often visible as a “sacral dimple” just lateral to the midline. How to identify specific vertebral |
Anatomy_Gray_205 | Anatomy_Gray | How to identify specific vertebral Identification of vertebral spinous processes (Fig. 2.67A) can be used to differentiate between regions of the vertebral column and facilitate visualizing the position of deeper structures, such as the inferior ends of the spinal cord and subarachnoid space. The spinous process of vertebra CII can be identified through deep palpation as the most superior bony protuberance in the midline inferior to the skull. Most of the other spinous processes, except for that of vertebra CVII, are not readily palpable because they are obscured by soft tissue. The spinous process of CVII is usually visible as a prominent eminence in the midline at the base of the neck (Fig. 2.67B), particularly when the neck is flexed. Extending between CVII and the external occipital protuberance of the skull is the ligamentum nuchae, which is readily apparent as a longitudinal ridge when the neck is flexed (Fig. 2.67C). | Anatomy_Gray. How to identify specific vertebral Identification of vertebral spinous processes (Fig. 2.67A) can be used to differentiate between regions of the vertebral column and facilitate visualizing the position of deeper structures, such as the inferior ends of the spinal cord and subarachnoid space. The spinous process of vertebra CII can be identified through deep palpation as the most superior bony protuberance in the midline inferior to the skull. Most of the other spinous processes, except for that of vertebra CVII, are not readily palpable because they are obscured by soft tissue. The spinous process of CVII is usually visible as a prominent eminence in the midline at the base of the neck (Fig. 2.67B), particularly when the neck is flexed. Extending between CVII and the external occipital protuberance of the skull is the ligamentum nuchae, which is readily apparent as a longitudinal ridge when the neck is flexed (Fig. 2.67C). |
Anatomy_Gray_206 | Anatomy_Gray | Extending between CVII and the external occipital protuberance of the skull is the ligamentum nuchae, which is readily apparent as a longitudinal ridge when the neck is flexed (Fig. 2.67C). Inferior to the spinous process of CVII is the spinous process of TI, which is also usually visible as a midline protuberance. Often it is more prominent than the spinous process of CVII (Fig. 2.67A,B). The root of the spine of the scapula is at the same level as the spinous process of vertebra TIII, and the inferior angle of the scapula is level with the spinous process of vertebra TVII (Fig. 2.67A). The spinous process of vertebra TXII is level with the midpoint of a vertical line between the inferior angle of the scapula and the iliac crest (Fig. 2.67A). | Anatomy_Gray. Extending between CVII and the external occipital protuberance of the skull is the ligamentum nuchae, which is readily apparent as a longitudinal ridge when the neck is flexed (Fig. 2.67C). Inferior to the spinous process of CVII is the spinous process of TI, which is also usually visible as a midline protuberance. Often it is more prominent than the spinous process of CVII (Fig. 2.67A,B). The root of the spine of the scapula is at the same level as the spinous process of vertebra TIII, and the inferior angle of the scapula is level with the spinous process of vertebra TVII (Fig. 2.67A). The spinous process of vertebra TXII is level with the midpoint of a vertical line between the inferior angle of the scapula and the iliac crest (Fig. 2.67A). |
Anatomy_Gray_207 | Anatomy_Gray | The spinous process of vertebra TXII is level with the midpoint of a vertical line between the inferior angle of the scapula and the iliac crest (Fig. 2.67A). A horizontal line between the highest point of the iliac crest on each side crosses through the spinous process of vertebra LIV. The LIII and LV vertebral spinous processes can be palpated above and below the LIV spinous process, respectively (Fig. 2.67A). The sacral dimples that mark the position of the posterior superior iliac spine are level with the SII vertebral spinous process (Fig. 2.67A). The tip of the coccyx is palpable at the base of the vertebral column between the gluteal masses (Fig. 2.67A). | Anatomy_Gray. The spinous process of vertebra TXII is level with the midpoint of a vertical line between the inferior angle of the scapula and the iliac crest (Fig. 2.67A). A horizontal line between the highest point of the iliac crest on each side crosses through the spinous process of vertebra LIV. The LIII and LV vertebral spinous processes can be palpated above and below the LIV spinous process, respectively (Fig. 2.67A). The sacral dimples that mark the position of the posterior superior iliac spine are level with the SII vertebral spinous process (Fig. 2.67A). The tip of the coccyx is palpable at the base of the vertebral column between the gluteal masses (Fig. 2.67A). |
Anatomy_Gray_208 | Anatomy_Gray | The tip of the coccyx is palpable at the base of the vertebral column between the gluteal masses (Fig. 2.67A). The tips of the vertebral spinous processes do not always lie in the same horizontal plane as their corresponding vertebral bodies. In thoracic regions, the spinous processes are long and sharply sloped downward so that their tips lie at the level of the vertebral body below. In other words, the tip of the TIII vertebral spinous process lies at vertebral level TIV. In lumbar and sacral regions, the spinous processes are generally shorter and less sloped than in thoracic regions, and their palpable tips more closely reflect the position of their corresponding vertebral bodies. As a consequence, the palpable end of the spinous process of vertebra LIV lies at approximately the LIV vertebral level. Visualizing the inferior ends of the spinal cord and subarachnoid space | Anatomy_Gray. The tip of the coccyx is palpable at the base of the vertebral column between the gluteal masses (Fig. 2.67A). The tips of the vertebral spinous processes do not always lie in the same horizontal plane as their corresponding vertebral bodies. In thoracic regions, the spinous processes are long and sharply sloped downward so that their tips lie at the level of the vertebral body below. In other words, the tip of the TIII vertebral spinous process lies at vertebral level TIV. In lumbar and sacral regions, the spinous processes are generally shorter and less sloped than in thoracic regions, and their palpable tips more closely reflect the position of their corresponding vertebral bodies. As a consequence, the palpable end of the spinous process of vertebra LIV lies at approximately the LIV vertebral level. Visualizing the inferior ends of the spinal cord and subarachnoid space |
Anatomy_Gray_209 | Anatomy_Gray | Visualizing the inferior ends of the spinal cord and subarachnoid space The spinal cord does not occupy the entire length of the vertebral canal. Normally in adults, it terminates at the level of the disc between vertebrae LI and LII; however, it may end as high as TXII or as low as the disc between vertebrae LII and LIII. The subarachnoid space ends at approximately the level of vertebra SII (Fig. 2.68A). | Anatomy_Gray. Visualizing the inferior ends of the spinal cord and subarachnoid space The spinal cord does not occupy the entire length of the vertebral canal. Normally in adults, it terminates at the level of the disc between vertebrae LI and LII; however, it may end as high as TXII or as low as the disc between vertebrae LII and LIII. The subarachnoid space ends at approximately the level of vertebra SII (Fig. 2.68A). |
Anatomy_Gray_210 | Anatomy_Gray | Because the subarachnoid space can be accessed in the lower lumbar region without endangering the spinal cord, it is important to be able to identify the position of the lumbar vertebral spinous processes. The LIV vertebral spinous process is level with a horizontal line between the highest points on the iliac crests. In the lumbar region, the palpable ends of the vertebral spinous processes lie opposite their corresponding vertebral bodies. The subarachnoid space can be accessed between vertebral levels LIII and LIV and between LIV and LV without endangering the spinal cord (Fig. 2.68B). The subarachnoid space ends at vertebral level SII, which is level with the sacral dimples marking the posterior superior iliac spines. | Anatomy_Gray. Because the subarachnoid space can be accessed in the lower lumbar region without endangering the spinal cord, it is important to be able to identify the position of the lumbar vertebral spinous processes. The LIV vertebral spinous process is level with a horizontal line between the highest points on the iliac crests. In the lumbar region, the palpable ends of the vertebral spinous processes lie opposite their corresponding vertebral bodies. The subarachnoid space can be accessed between vertebral levels LIII and LIV and between LIV and LV without endangering the spinal cord (Fig. 2.68B). The subarachnoid space ends at vertebral level SII, which is level with the sacral dimples marking the posterior superior iliac spines. |
Anatomy_Gray_211 | Anatomy_Gray | A number of intrinsic and extrinsic muscles of the back can readily be observed and palpated. The largest of these are the trapezius and latissimus dorsi muscles (Fig. 2.69A and 2.69B). Retracting the scapulae toward the midline can accentuate the rhomboid muscles (Fig. 2.69C), which lie deep to the trapezius muscle. The erector spinae muscles are visible as two longitudinal columns separated by a furrow in the midline (Fig. 2.69A). Fig. 2.1 Skeletal framework of the back. Fig. 2.2 Curvatures of the vertebral column. Cervical curvature(secondary curvature)Thoracic curvature(primary curvature)Lumbar curvature(secondary curvature)Sacral/coccygeal curvature(primary curvature)Gravity lineConcave primarycurvature of backEarly embryoAdultSomites Fig. 2.3 Back movements. Fig. 2.4 Nervous system. Fig. 2.5 Vertebrae. Fig. 2.6 A typical vertebra. A. Superior view. B. Lateral view. Fig. 2.7 Back muscles. A. Extrinsic muscles. B. Intrinsic muscles. | Anatomy_Gray. A number of intrinsic and extrinsic muscles of the back can readily be observed and palpated. The largest of these are the trapezius and latissimus dorsi muscles (Fig. 2.69A and 2.69B). Retracting the scapulae toward the midline can accentuate the rhomboid muscles (Fig. 2.69C), which lie deep to the trapezius muscle. The erector spinae muscles are visible as two longitudinal columns separated by a furrow in the midline (Fig. 2.69A). Fig. 2.1 Skeletal framework of the back. Fig. 2.2 Curvatures of the vertebral column. Cervical curvature(secondary curvature)Thoracic curvature(primary curvature)Lumbar curvature(secondary curvature)Sacral/coccygeal curvature(primary curvature)Gravity lineConcave primarycurvature of backEarly embryoAdultSomites Fig. 2.3 Back movements. Fig. 2.4 Nervous system. Fig. 2.5 Vertebrae. Fig. 2.6 A typical vertebra. A. Superior view. B. Lateral view. Fig. 2.7 Back muscles. A. Extrinsic muscles. B. Intrinsic muscles. |
Anatomy_Gray_212 | Anatomy_Gray | Fig. 2.4 Nervous system. Fig. 2.5 Vertebrae. Fig. 2.6 A typical vertebra. A. Superior view. B. Lateral view. Fig. 2.7 Back muscles. A. Extrinsic muscles. B. Intrinsic muscles. Deep groupSerratus posteriorinferiorSerratus posteriorsuperiorSuboccipitalLevator scapulaeSpleniusRhomboid minorSuperficial groupABIntermediate groupIntrinsic musclesTrue back muscles innervated by posterior rami of spinal nervesRhomboid majorSpinalisIliocostalisErector spinaeLongissimusLatissimusdorsiTrapeziusExtrinsic musclesInnervated by anterior rami of spinal nerves or cranial nerve XI (trapezius) Fig. 2.8 Vertebral canal. Spinal cordPia materSubarachnoid spaceDura materArachnoid materAnterior ramusPosterior ramusPosition of spinal ganglionTransverseprocessSpinousprocessPosterior longitudinalligamentAnterior internal vertebralvenous plexusIntervertebral discExtradural spaceExtradural fatVertebral body Fig. 2.9 Spinal nerves (transverse section). Fig. 2.10 Relationships of the back to other regions. | Anatomy_Gray. Fig. 2.4 Nervous system. Fig. 2.5 Vertebrae. Fig. 2.6 A typical vertebra. A. Superior view. B. Lateral view. Fig. 2.7 Back muscles. A. Extrinsic muscles. B. Intrinsic muscles. Deep groupSerratus posteriorinferiorSerratus posteriorsuperiorSuboccipitalLevator scapulaeSpleniusRhomboid minorSuperficial groupABIntermediate groupIntrinsic musclesTrue back muscles innervated by posterior rami of spinal nervesRhomboid majorSpinalisIliocostalisErector spinaeLongissimusLatissimusdorsiTrapeziusExtrinsic musclesInnervated by anterior rami of spinal nerves or cranial nerve XI (trapezius) Fig. 2.8 Vertebral canal. Spinal cordPia materSubarachnoid spaceDura materArachnoid materAnterior ramusPosterior ramusPosition of spinal ganglionTransverseprocessSpinousprocessPosterior longitudinalligamentAnterior internal vertebralvenous plexusIntervertebral discExtradural spaceExtradural fatVertebral body Fig. 2.9 Spinal nerves (transverse section). Fig. 2.10 Relationships of the back to other regions. |
Anatomy_Gray_213 | Anatomy_Gray | Fig. 2.9 Spinal nerves (transverse section). Fig. 2.10 Relationships of the back to other regions. Cervical region• supports and moves head• transmits spinal cord and vertebral arteries between head and neck Thoracic region• support for thoraxLumbar region• support for abdomenSacral region• transmits weight to lower limbs through pelvic bones• framework for posterior aspect of pelvisVertebral arteries travelin transverse processes ofC6-C1, then pass throughforamen magnum Fig. 2.11 Vertebral canal, spinal cord, and spinal nerves. 1121110112233445595678412345678123C8T1T2T3T4T5T6T7T8T9T10T11T12L1L2L3L4L5S1S2S3S4S5CoC7C6C5C4Cervicalenlargement(of spinal cord)C2C3C1SubarachnoidspaceLumbosacralenlargement(of spinal cord)Arachnoid materEnd of spinalcord at LI–LIIvertebraeEnd ofsubarachnoidspace–sacralvertebra IIDura materPedicles ofvertebraeSpinalganglion Fig. 2.12 Intervertebral foramina. Fig. 2.13 Dermatomes innervated by posterior rami of spinal nerves. | Anatomy_Gray. Fig. 2.9 Spinal nerves (transverse section). Fig. 2.10 Relationships of the back to other regions. Cervical region• supports and moves head• transmits spinal cord and vertebral arteries between head and neck Thoracic region• support for thoraxLumbar region• support for abdomenSacral region• transmits weight to lower limbs through pelvic bones• framework for posterior aspect of pelvisVertebral arteries travelin transverse processes ofC6-C1, then pass throughforamen magnum Fig. 2.11 Vertebral canal, spinal cord, and spinal nerves. 1121110112233445595678412345678123C8T1T2T3T4T5T6T7T8T9T10T11T12L1L2L3L4L5S1S2S3S4S5CoC7C6C5C4Cervicalenlargement(of spinal cord)C2C3C1SubarachnoidspaceLumbosacralenlargement(of spinal cord)Arachnoid materEnd of spinalcord at LI–LIIvertebraeEnd ofsubarachnoidspace–sacralvertebra IIDura materPedicles ofvertebraeSpinalganglion Fig. 2.12 Intervertebral foramina. Fig. 2.13 Dermatomes innervated by posterior rami of spinal nerves. |
Anatomy_Gray_214 | Anatomy_Gray | Fig. 2.12 Intervertebral foramina. Fig. 2.13 Dermatomes innervated by posterior rami of spinal nerves. C2C3C4T2T3T4T5T6T7T8T9L5S1S2S4S3S5, Co*The dorsal rami of L4 and L5 may not have cutaneousbranches and may therefore not be represented asdermatomes on the backL4L3L2L1T11T12T10 Fig. 2.14 Vertebrae. Fig. 2.15 Radiograph of cervical region of vertebral column. A. Anteroposterior view. B. Lateral view. ARib IICIISpinous process of CVII Vertebralbody of CIIILocation ofintervertebral discVertebra prominens(spinous process of CVII)Posterior tubercleof CI (atlas)B Fig. 2.16 Radiograph of thoracic region of vertebral column. A. Anteroposterior view. B. Lateral view. RibPedicleLocation of intervertebral discSpinous processTransverse processVertebral bodyA BIntervertebral foramenVertebral bodyLocation of intervertebral disc Fig. 2.17 Radiograph of lumbar region of vertebral column. A. Anteroposterior view. B. Lateral view. RibTransverse processPedicleSpinous process of LIVA | Anatomy_Gray. Fig. 2.12 Intervertebral foramina. Fig. 2.13 Dermatomes innervated by posterior rami of spinal nerves. C2C3C4T2T3T4T5T6T7T8T9L5S1S2S4S3S5, Co*The dorsal rami of L4 and L5 may not have cutaneousbranches and may therefore not be represented asdermatomes on the backL4L3L2L1T11T12T10 Fig. 2.14 Vertebrae. Fig. 2.15 Radiograph of cervical region of vertebral column. A. Anteroposterior view. B. Lateral view. ARib IICIISpinous process of CVII Vertebralbody of CIIILocation ofintervertebral discVertebra prominens(spinous process of CVII)Posterior tubercleof CI (atlas)B Fig. 2.16 Radiograph of thoracic region of vertebral column. A. Anteroposterior view. B. Lateral view. RibPedicleLocation of intervertebral discSpinous processTransverse processVertebral bodyA BIntervertebral foramenVertebral bodyLocation of intervertebral disc Fig. 2.17 Radiograph of lumbar region of vertebral column. A. Anteroposterior view. B. Lateral view. RibTransverse processPedicleSpinous process of LIVA |
Anatomy_Gray_215 | Anatomy_Gray | Fig. 2.17 Radiograph of lumbar region of vertebral column. A. Anteroposterior view. B. Lateral view. RibTransverse processPedicleSpinous process of LIVA Location ofintervertebral discVertebral body of LIIIIntervertebral foramenB Fig. 2.18 Development of the vertebrae. Fig. 2.19 Typical vertebra. Fig. 2.20 Regional vertebrae. A. Typical cervical vertebra. B. Atlas and axis. C. Typical thoracic vertebra. D. Typical lumbar vertebra. E. Sacrum. F. Coccyx. | Anatomy_Gray. Fig. 2.17 Radiograph of lumbar region of vertebral column. A. Anteroposterior view. B. Lateral view. RibTransverse processPedicleSpinous process of LIVA Location ofintervertebral discVertebral body of LIIIIntervertebral foramenB Fig. 2.18 Development of the vertebrae. Fig. 2.19 Typical vertebra. Fig. 2.20 Regional vertebrae. A. Typical cervical vertebra. B. Atlas and axis. C. Typical thoracic vertebra. D. Typical lumbar vertebra. E. Sacrum. F. Coccyx. |
Anatomy_Gray_216 | Anatomy_Gray | E. Sacrum. F. Coccyx. Transverse processDensDensForamen transversariumSuperior viewSuperior viewSuperior viewPosterior viewPosterosuperior viewBAnterior tuberclePosterior tubercleAnterior archLateral massPosterior archFacet for densFacet for occipital condyleImpressionsfor alarligamentsAlarligamentsTectorial membrane (upper partof posterior longitudinal ligament)PosteriorlongitudinalligamentFacets forattachment ofalar ligamentsAtlas (CI vertebra)Atlas (CI vertebra) and Axis (CII vertebra)Atlas (CIvertebra)and Axis(CII vertebra)and baseof skullAxis (CII vertebra)Transverse ligament of atlasTransverse ligament of atlasVertebral bodyTransverse processTransverseprocessSpinousprocessMammillaryprocessSpinousprocessSuperior viewLateral viewSuperior viewFacet for articulationwith tubercle ofits own ribDemifacet for articulationwith head of rib belowDemifacet for articulationwith head of its own ribCDApical ligamentof densInferior longitudinalband of cruciformligament | Anatomy_Gray. E. Sacrum. F. Coccyx. Transverse processDensDensForamen transversariumSuperior viewSuperior viewSuperior viewPosterior viewPosterosuperior viewBAnterior tuberclePosterior tubercleAnterior archLateral massPosterior archFacet for densFacet for occipital condyleImpressionsfor alarligamentsAlarligamentsTectorial membrane (upper partof posterior longitudinal ligament)PosteriorlongitudinalligamentFacets forattachment ofalar ligamentsAtlas (CI vertebra)Atlas (CI vertebra) and Axis (CII vertebra)Atlas (CIvertebra)and Axis(CII vertebra)and baseof skullAxis (CII vertebra)Transverse ligament of atlasTransverse ligament of atlasVertebral bodyTransverse processTransverseprocessSpinousprocessMammillaryprocessSpinousprocessSuperior viewLateral viewSuperior viewFacet for articulationwith tubercle ofits own ribDemifacet for articulationwith head of rib belowDemifacet for articulationwith head of its own ribCDApical ligamentof densInferior longitudinalband of cruciformligament |
Anatomy_Gray_217 | Anatomy_Gray | Anterior viewDorsolateral viewPosterior viewFacet for articulation with pelvic boneEFAnterior sacral foraminaPosterior sacral foraminaCoccygeal cornuIncomplete sacral canal Fig. 2.21 Radiograph showing CI (atlas) and CII (axis) vertebrae. Open mouth, anteroposterior (odontoid peg) view. Superior articularfacet of CIIDensInferior articular faceton lateral mass of CI Fig. 2.22 Intervertebral foramen. Fig. 2.23 Spaces between adjacent vertebral arches in the lumbar region. Fig. 2.24 T1-weighted MR image in the sagittal plane demonstrating a lumbosacral myelomeningocele. There is an absence of laminae and spinous processes in the lumbosacral region. Fig. 2.25 Radiograph of the lumbar region of the vertebral column demonstrating a wedge fracture of the L1 vertebra. This condition is typically seen in patients with osteoporosis. | Anatomy_Gray. Anterior viewDorsolateral viewPosterior viewFacet for articulation with pelvic boneEFAnterior sacral foraminaPosterior sacral foraminaCoccygeal cornuIncomplete sacral canal Fig. 2.21 Radiograph showing CI (atlas) and CII (axis) vertebrae. Open mouth, anteroposterior (odontoid peg) view. Superior articularfacet of CIIDensInferior articular faceton lateral mass of CI Fig. 2.22 Intervertebral foramen. Fig. 2.23 Spaces between adjacent vertebral arches in the lumbar region. Fig. 2.24 T1-weighted MR image in the sagittal plane demonstrating a lumbosacral myelomeningocele. There is an absence of laminae and spinous processes in the lumbosacral region. Fig. 2.25 Radiograph of the lumbar region of the vertebral column demonstrating a wedge fracture of the L1 vertebra. This condition is typically seen in patients with osteoporosis. |
Anatomy_Gray_218 | Anatomy_Gray | Fig. 2.25 Radiograph of the lumbar region of the vertebral column demonstrating a wedge fracture of the L1 vertebra. This condition is typically seen in patients with osteoporosis. Fig. 2.26 Radiograph of the lumbar region of the vertebral column demonstrating three intrapedicular needles, all of which have been placed into the middle of the vertebral bodies. The high-density material is radiopaque bone cement, which has been injected as a liquid that will harden. Fig. 2.27 Severe scoliosis. A. Radiograph, anteroposterior view. B. Volume-rendered CT, anterior view. Fig. 2.28 Sagittal CT showing kyphosis. Fig. 2.29 Variations in vertebral number. A. Fused vertebral bodies of cervical vertebrae. B. Hemivertebra. C. Axial slice MRI through the LV vertebra. The iliolumbar ligament runs from the tip of the LV vertebra transverse process to the iliac crest. Fused bodies of cervical vertebraeA HemivertebraPartial lumbarization of first sacral vertebraB | Anatomy_Gray. Fig. 2.25 Radiograph of the lumbar region of the vertebral column demonstrating a wedge fracture of the L1 vertebra. This condition is typically seen in patients with osteoporosis. Fig. 2.26 Radiograph of the lumbar region of the vertebral column demonstrating three intrapedicular needles, all of which have been placed into the middle of the vertebral bodies. The high-density material is radiopaque bone cement, which has been injected as a liquid that will harden. Fig. 2.27 Severe scoliosis. A. Radiograph, anteroposterior view. B. Volume-rendered CT, anterior view. Fig. 2.28 Sagittal CT showing kyphosis. Fig. 2.29 Variations in vertebral number. A. Fused vertebral bodies of cervical vertebrae. B. Hemivertebra. C. Axial slice MRI through the LV vertebra. The iliolumbar ligament runs from the tip of the LV vertebra transverse process to the iliac crest. Fused bodies of cervical vertebraeA HemivertebraPartial lumbarization of first sacral vertebraB |
Anatomy_Gray_219 | Anatomy_Gray | Fused bodies of cervical vertebraeA HemivertebraPartial lumbarization of first sacral vertebraB Fig. 2.30 A. MRI of a spine with multiple collapsed vertebrae due to diffuse metastatic myeloma infiltration. B1, B2. Positron emission tomography CT (PETCT) study detecting cancer cells in the spine that have high glucose metabolism. Fig. 2.31 Intervertebral joints. Anulus fibrosusNucleus pulposusLayer of hyalinecartilage Fig. 2.32 Zygapophysial joints. Fig. 2.33 Uncovertebral joint. Fig. 2.34 Disc protrusion. T2-weighted magnetic resonance images of the lumbar region of the vertebral column. A. Sagittal plane. B. Axial plane. Fig. 2.35 Anterior and posterior longitudinal ligaments of vertebral column. Fig. 2.36 Ligamenta flava. Fig. 2.37 Supraspinous ligament and ligamentum nuchae. Fig. 2.38 Interspinous ligaments. Fig. 2.39 Axial slice MRI through the lumbar spine demonstrating bilateral hypertrophy of the ligamentum flavum. | Anatomy_Gray. Fused bodies of cervical vertebraeA HemivertebraPartial lumbarization of first sacral vertebraB Fig. 2.30 A. MRI of a spine with multiple collapsed vertebrae due to diffuse metastatic myeloma infiltration. B1, B2. Positron emission tomography CT (PETCT) study detecting cancer cells in the spine that have high glucose metabolism. Fig. 2.31 Intervertebral joints. Anulus fibrosusNucleus pulposusLayer of hyalinecartilage Fig. 2.32 Zygapophysial joints. Fig. 2.33 Uncovertebral joint. Fig. 2.34 Disc protrusion. T2-weighted magnetic resonance images of the lumbar region of the vertebral column. A. Sagittal plane. B. Axial plane. Fig. 2.35 Anterior and posterior longitudinal ligaments of vertebral column. Fig. 2.36 Ligamenta flava. Fig. 2.37 Supraspinous ligament and ligamentum nuchae. Fig. 2.38 Interspinous ligaments. Fig. 2.39 Axial slice MRI through the lumbar spine demonstrating bilateral hypertrophy of the ligamentum flavum. |
Anatomy_Gray_220 | Anatomy_Gray | Fig. 2.38 Interspinous ligaments. Fig. 2.39 Axial slice MRI through the lumbar spine demonstrating bilateral hypertrophy of the ligamentum flavum. Fig. 2.40 Radiograph of lumbar region of vertebral column, oblique view (“Scottie dog”). A. Normal radiograph of lumbar region of vertebral column, oblique view. In this view, the transverse process (nose), pedicle (eye), superior articular process (ear), inferior articular process (front leg), and pars interarticularis (neck) resemble a dog. A fracture of the pars interarticularis is visible as a break in the neck of the dog, or the appearance of a collar. B. Fracture of pars interarticularis. C. CT of lumbar spine shows fracture of the LV pars interarticularis. Fig. 2.41 A. Anterior lumbar interbody fusion (ALIF). B. Posterior lumbar interbody fusion (PLIF). Fig. 2.42 Superficial group of back muscles—trapezius and latissimus dorsi. | Anatomy_Gray. Fig. 2.38 Interspinous ligaments. Fig. 2.39 Axial slice MRI through the lumbar spine demonstrating bilateral hypertrophy of the ligamentum flavum. Fig. 2.40 Radiograph of lumbar region of vertebral column, oblique view (“Scottie dog”). A. Normal radiograph of lumbar region of vertebral column, oblique view. In this view, the transverse process (nose), pedicle (eye), superior articular process (ear), inferior articular process (front leg), and pars interarticularis (neck) resemble a dog. A fracture of the pars interarticularis is visible as a break in the neck of the dog, or the appearance of a collar. B. Fracture of pars interarticularis. C. CT of lumbar spine shows fracture of the LV pars interarticularis. Fig. 2.41 A. Anterior lumbar interbody fusion (ALIF). B. Posterior lumbar interbody fusion (PLIF). Fig. 2.42 Superficial group of back muscles—trapezius and latissimus dorsi. |
Anatomy_Gray_221 | Anatomy_Gray | Fig. 2.41 A. Anterior lumbar interbody fusion (ALIF). B. Posterior lumbar interbody fusion (PLIF). Fig. 2.42 Superficial group of back muscles—trapezius and latissimus dorsi. Spinous process of CVIIAcromionSpine of scapulaIliac crestGreater occipital nerve(posterior ramus of C2)Third occipital nerve(posterior ramus of C3)Medial branches of posterior ramiLateral branches of posterior ramiTrapeziusLatissimus dorsiThoracolumbar fascia Fig. 2.43 Superficial group of back muscles—trapezius and latissimus dorsi, with rhomboid major, rhomboid minor, and levator scapulae located deep to trapezius in the superior part of the back. Fig. 2.44 Innervation and blood supply of trapezius. TrapeziusLatissimus dorsiRhomboid minorRhomboid majorLevator scapulaeAccessory nerve [XI]Superficial branch of transverse cervical artery Fig. 2.45 Rhomboid muscles and levator scapulae. Fig. 2.46 Innervation and blood supply of the rhomboid muscles. | Anatomy_Gray. Fig. 2.41 A. Anterior lumbar interbody fusion (ALIF). B. Posterior lumbar interbody fusion (PLIF). Fig. 2.42 Superficial group of back muscles—trapezius and latissimus dorsi. Spinous process of CVIIAcromionSpine of scapulaIliac crestGreater occipital nerve(posterior ramus of C2)Third occipital nerve(posterior ramus of C3)Medial branches of posterior ramiLateral branches of posterior ramiTrapeziusLatissimus dorsiThoracolumbar fascia Fig. 2.43 Superficial group of back muscles—trapezius and latissimus dorsi, with rhomboid major, rhomboid minor, and levator scapulae located deep to trapezius in the superior part of the back. Fig. 2.44 Innervation and blood supply of trapezius. TrapeziusLatissimus dorsiRhomboid minorRhomboid majorLevator scapulaeAccessory nerve [XI]Superficial branch of transverse cervical artery Fig. 2.45 Rhomboid muscles and levator scapulae. Fig. 2.46 Innervation and blood supply of the rhomboid muscles. |
Anatomy_Gray_222 | Anatomy_Gray | Fig. 2.45 Rhomboid muscles and levator scapulae. Fig. 2.46 Innervation and blood supply of the rhomboid muscles. Dorsal scapular nerveTrapeziusLatissimus dorsiRhomboid minorRhomboid majorLevator scapulaeSuperficial branch of transverse cervical arteryDeep branch of transverse cervical artery Fig. 2.47 Intermediate group of back muscles—serratus posterior muscles. Fig. 2.48 Thoracolumbar fascia and the deep back muscles (transverse section). Fig. 2.49 Deep group of back muscles—spinotransversales muscles (splenius capitis and splenius cervicis). Fig. 2.50 Deep group of back muscles—erector spinae muscles. Spinous process of CVIIIliac crestSplenius capitisLongissimus capitis Ligamentum nuchaeLongissimus thoracisLongissimus cervicisSpinalis thoracisSpinalisIliocostalis lumborum Iliocostalis thoracisIliocostalis cervicisIliocostalisLongissimus Fig. 2.51 Deep group of back muscles—transversospinales and segmental muscles. | Anatomy_Gray. Fig. 2.45 Rhomboid muscles and levator scapulae. Fig. 2.46 Innervation and blood supply of the rhomboid muscles. Dorsal scapular nerveTrapeziusLatissimus dorsiRhomboid minorRhomboid majorLevator scapulaeSuperficial branch of transverse cervical arteryDeep branch of transverse cervical artery Fig. 2.47 Intermediate group of back muscles—serratus posterior muscles. Fig. 2.48 Thoracolumbar fascia and the deep back muscles (transverse section). Fig. 2.49 Deep group of back muscles—spinotransversales muscles (splenius capitis and splenius cervicis). Fig. 2.50 Deep group of back muscles—erector spinae muscles. Spinous process of CVIIIliac crestSplenius capitisLongissimus capitis Ligamentum nuchaeLongissimus thoracisLongissimus cervicisSpinalis thoracisSpinalisIliocostalis lumborum Iliocostalis thoracisIliocostalis cervicisIliocostalisLongissimus Fig. 2.51 Deep group of back muscles—transversospinales and segmental muscles. |
Anatomy_Gray_223 | Anatomy_Gray | Fig. 2.51 Deep group of back muscles—transversospinales and segmental muscles. Spinous process of CVIIObliquus capitis inferiorObliquus capitis superiorRectus capitis posterior minorRectus capitis posterior majorSemispinalis thoracisIntertransversariusErector spinaeRotatores thoracis(short, long)Levatores costarum(short, long)Semispinalis capitisMultifidus Fig. 2.52 Deep group of back muscles—suboccipital muscles. This also shows the borders of the suboccipital triangle. Spinous process of CIIPosterior ramus of C1Obliquus capitis superior Rectus capitis posterior minorObliquus capitis inferiorRectus capitis posterior majorSplenius capitisSplenius capitisLongissimus capitisSemispinalis cervicisSemispinalis capitisSemispinalis capitisVertebral artery Fig. 2.53 Spinal cord. | Anatomy_Gray. Fig. 2.51 Deep group of back muscles—transversospinales and segmental muscles. Spinous process of CVIIObliquus capitis inferiorObliquus capitis superiorRectus capitis posterior minorRectus capitis posterior majorSemispinalis thoracisIntertransversariusErector spinaeRotatores thoracis(short, long)Levatores costarum(short, long)Semispinalis capitisMultifidus Fig. 2.52 Deep group of back muscles—suboccipital muscles. This also shows the borders of the suboccipital triangle. Spinous process of CIIPosterior ramus of C1Obliquus capitis superior Rectus capitis posterior minorObliquus capitis inferiorRectus capitis posterior majorSplenius capitisSplenius capitisLongissimus capitisSemispinalis cervicisSemispinalis capitisSemispinalis capitisVertebral artery Fig. 2.53 Spinal cord. |
Anatomy_Gray_224 | Anatomy_Gray | Fig. 2.53 Spinal cord. End of spinalcord LI–LIIConus medullarisInferior part ofarachnoid materEnd of subarachnoidspace SIICervicalenlargement(of spinal cord)Lumbosacralenlargement(of spinal cord)FilumterminalePial partDural partPedicles ofvertebrae Fig. 2.54 Features of the spinal cord. Fig. 2.55 Arteries that supply the spinal cord. A. Anterior view of spinal cord (not all segmental spinal arteries are shown). B. Segmental supply of spinal cord. Posterior spinal arteryADeep cervical arteryCostocervical trunkThyrocervical trunkSubclavian arteryPosterior intercostalarterySegmentalspinal arteryArtery of Adamkiewicz(branch fromsegmentalspinal artery)Ascending cervicalarteryVertebral arterySegmental medullaryarteriesAnterior spinal arterySegmental medullaryarteries (branch fromsegmental spinalartery)Lateral sacral arterySegmentalspinal artery Fig. 2.56 Veins that drain the spinal cord. | Anatomy_Gray. Fig. 2.53 Spinal cord. End of spinalcord LI–LIIConus medullarisInferior part ofarachnoid materEnd of subarachnoidspace SIICervicalenlargement(of spinal cord)Lumbosacralenlargement(of spinal cord)FilumterminalePial partDural partPedicles ofvertebrae Fig. 2.54 Features of the spinal cord. Fig. 2.55 Arteries that supply the spinal cord. A. Anterior view of spinal cord (not all segmental spinal arteries are shown). B. Segmental supply of spinal cord. Posterior spinal arteryADeep cervical arteryCostocervical trunkThyrocervical trunkSubclavian arteryPosterior intercostalarterySegmentalspinal arteryArtery of Adamkiewicz(branch fromsegmentalspinal artery)Ascending cervicalarteryVertebral arterySegmental medullaryarteriesAnterior spinal arterySegmental medullaryarteries (branch fromsegmental spinalartery)Lateral sacral arterySegmentalspinal artery Fig. 2.56 Veins that drain the spinal cord. |
Anatomy_Gray_225 | Anatomy_Gray | Fig. 2.56 Veins that drain the spinal cord. Fig. 2.57 MRI of the spine. There is discitis of the T10-T11 intervertebral disc with destruction of the adjacent endplates. There is also a prevertebral abscess and an epidural abscess, which impinges the cord. Fig. 2.58 CT at the level of CI demonstrates two breaks in the closed ring of the atlas following an axial-loading injury. Fig. 2.59 Meninges. Fig. 2.60 Arrangement of structures in the vertebral canal and the back (lumbar region). Crura of diaphragmAortaPsoasDuraQuadratus lumborumInternal vertebral plexus of veinsin extradural spaceErector spinae musclesLigamenta flavaSupraspinous ligamentInterspinous ligamentLumbar arteryVeinCauda equinaSkinVertebraIntervertebral discIntervertebral foramenLaminaPediclePosterior longitudinal ligament Fig. 2.61 Basic organization of a spinal nerve. Fig. 2.62 Course of spinal nerves in the vertebral canal. | Anatomy_Gray. Fig. 2.56 Veins that drain the spinal cord. Fig. 2.57 MRI of the spine. There is discitis of the T10-T11 intervertebral disc with destruction of the adjacent endplates. There is also a prevertebral abscess and an epidural abscess, which impinges the cord. Fig. 2.58 CT at the level of CI demonstrates two breaks in the closed ring of the atlas following an axial-loading injury. Fig. 2.59 Meninges. Fig. 2.60 Arrangement of structures in the vertebral canal and the back (lumbar region). Crura of diaphragmAortaPsoasDuraQuadratus lumborumInternal vertebral plexus of veinsin extradural spaceErector spinae musclesLigamenta flavaSupraspinous ligamentInterspinous ligamentLumbar arteryVeinCauda equinaSkinVertebraIntervertebral discIntervertebral foramenLaminaPediclePosterior longitudinal ligament Fig. 2.61 Basic organization of a spinal nerve. Fig. 2.62 Course of spinal nerves in the vertebral canal. |
Anatomy_Gray_226 | Anatomy_Gray | Fig. 2.61 Basic organization of a spinal nerve. Fig. 2.62 Course of spinal nerves in the vertebral canal. 1121110112233445595678412345678123C8T1T2T3T4T5T6T7T8T9T10T11T12L1L2L3L4L5S1S2S3S4S5CoC7C6C5C4Cervical enlargement(of spinal cord)C2C3C1Lumbosacral enlargement(of spinal cord)Cauda equinaPedicles of vertebraeSpinal ganglion Fig. 2.63 Nomenclature of the spinal nerves. Nerve C1 emerges betweenskull and CI vertebraNerve C8 emerges inferior topedicle of CVII vertebraNerves C2 to C7 emergesuperior to pediclesNerves T1 to Co emergeinferior to pedicles oftheir respective vertebraeC2C1C3C4C5C6C7C8T1CICVIITIPedicleTransition innomenclatureof nervesT2 Fig. 2.64 Normal appearance of the back. A. In women. B. In men. Fig. 2.65 Normal curvatures of the vertebral column. Fig. 2.66 Back of a woman with major palpable bony landmarks indicated. | Anatomy_Gray. Fig. 2.61 Basic organization of a spinal nerve. Fig. 2.62 Course of spinal nerves in the vertebral canal. 1121110112233445595678412345678123C8T1T2T3T4T5T6T7T8T9T10T11T12L1L2L3L4L5S1S2S3S4S5CoC7C6C5C4Cervical enlargement(of spinal cord)C2C3C1Lumbosacral enlargement(of spinal cord)Cauda equinaPedicles of vertebraeSpinal ganglion Fig. 2.63 Nomenclature of the spinal nerves. Nerve C1 emerges betweenskull and CI vertebraNerve C8 emerges inferior topedicle of CVII vertebraNerves C2 to C7 emergesuperior to pediclesNerves T1 to Co emergeinferior to pedicles oftheir respective vertebraeC2C1C3C4C5C6C7C8T1CICVIITIPedicleTransition innomenclatureof nervesT2 Fig. 2.64 Normal appearance of the back. A. In women. B. In men. Fig. 2.65 Normal curvatures of the vertebral column. Fig. 2.66 Back of a woman with major palpable bony landmarks indicated. |
Anatomy_Gray_227 | Anatomy_Gray | Fig. 2.64 Normal appearance of the back. A. In women. B. In men. Fig. 2.65 Normal curvatures of the vertebral column. Fig. 2.66 Back of a woman with major palpable bony landmarks indicated. Spine of scapulaInferior angle of scapulaMedial border of scapulaPosition of externaloccipital protuberancePosterior superior iliac spineIliac crest Fig. 2.67 The back with the positions of vertebral spinous processes and associated structures indicated. A. In a man. B. In a woman with neck flexed. The prominent CVII and TI vertebral spinous processes are labeled. C. In a woman with neck flexed to accentuate the ligamentum nuchae. | Anatomy_Gray. Fig. 2.64 Normal appearance of the back. A. In women. B. In men. Fig. 2.65 Normal curvatures of the vertebral column. Fig. 2.66 Back of a woman with major palpable bony landmarks indicated. Spine of scapulaInferior angle of scapulaMedial border of scapulaPosition of externaloccipital protuberancePosterior superior iliac spineIliac crest Fig. 2.67 The back with the positions of vertebral spinous processes and associated structures indicated. A. In a man. B. In a woman with neck flexed. The prominent CVII and TI vertebral spinous processes are labeled. C. In a woman with neck flexed to accentuate the ligamentum nuchae. |
Anatomy_Gray_228 | Anatomy_Gray | Tip of coccyxSII vertebral spinous processTXII vertebral spinous processTVII vertebral spinous processTIII vertebral spinous processTI vertebral spinous processRoot of spine of scapulaInferior angle of scapulaHighest point of iliac crestIliac crestSacral dimpleCVII vertebral spinous processCII vertebral spinous processPosition of externaloccipital protuberanceLIV vertebral spinous processA Fig. 2.68 Back with the ends of the spinal cord and subarachnoid space indicated. A. In a man. Back with the ends of the spinal cord and subarachnoid space indicated. B. In a woman lying on her side in a fetal position, which accentuates the lumbar vertebral spinous processes and opens the spaces between adjacent vertebral arches. Cerebrospinal fluid can be withdrawn from the subarachnoid space in lower lumbar regions without endangering the spinal cord. | Anatomy_Gray. Tip of coccyxSII vertebral spinous processTXII vertebral spinous processTVII vertebral spinous processTIII vertebral spinous processTI vertebral spinous processRoot of spine of scapulaInferior angle of scapulaHighest point of iliac crestIliac crestSacral dimpleCVII vertebral spinous processCII vertebral spinous processPosition of externaloccipital protuberanceLIV vertebral spinous processA Fig. 2.68 Back with the ends of the spinal cord and subarachnoid space indicated. A. In a man. Back with the ends of the spinal cord and subarachnoid space indicated. B. In a woman lying on her side in a fetal position, which accentuates the lumbar vertebral spinous processes and opens the spaces between adjacent vertebral arches. Cerebrospinal fluid can be withdrawn from the subarachnoid space in lower lumbar regions without endangering the spinal cord. |
Anatomy_Gray_229 | Anatomy_Gray | Tip of coccyxSII vertebral spinous processTXII vertebral spinous processInferior end of spinal cord(normally betweenLI and LII vertebra)Inferior end ofsubarachnoid spaceALIV vertebral spinous process LIV vertebral spinous processNeedleLV vertebral spinous processTip of coccyxB Fig. 2.69 Back muscles. A. In a man with latissimus dorsi, trapezius, and erector spinae muscles outlined. Back muscles. B. In a man with arms abducted to accentuate the lateral margins of the latissimus dorsi muscles. C. In a woman with scapulae externally rotated and forcibly retracted to accentuate the rhomboid muscles. Fig. 2.70 MRI of the lumbar spine reveals posterior herniation of the L2-3 disc resulting in compression of the cauda equina filaments. Table 2.1 Superficial (appendicular) group of back muscles Table 2.2 Intermediate (respiratory) group of back muscles Table 2.3 Spinotransversales muscles Table 2.4 Erector spinae group of back muscles | Anatomy_Gray. Tip of coccyxSII vertebral spinous processTXII vertebral spinous processInferior end of spinal cord(normally betweenLI and LII vertebra)Inferior end ofsubarachnoid spaceALIV vertebral spinous process LIV vertebral spinous processNeedleLV vertebral spinous processTip of coccyxB Fig. 2.69 Back muscles. A. In a man with latissimus dorsi, trapezius, and erector spinae muscles outlined. Back muscles. B. In a man with arms abducted to accentuate the lateral margins of the latissimus dorsi muscles. C. In a woman with scapulae externally rotated and forcibly retracted to accentuate the rhomboid muscles. Fig. 2.70 MRI of the lumbar spine reveals posterior herniation of the L2-3 disc resulting in compression of the cauda equina filaments. Table 2.1 Superficial (appendicular) group of back muscles Table 2.2 Intermediate (respiratory) group of back muscles Table 2.3 Spinotransversales muscles Table 2.4 Erector spinae group of back muscles |
Anatomy_Gray_230 | Anatomy_Gray | Table 2.2 Intermediate (respiratory) group of back muscles Table 2.3 Spinotransversales muscles Table 2.4 Erector spinae group of back muscles Table 2.5 Transversospinales group of back muscles Table 2.6 Segmental back muscles Table 2.7 Suboccipital group of back muscles In the clinic Spina bifida is a disorder in which the two sides of vertebral arches, usually in lower vertebrae, fail to fuse during development, resulting in an “open” vertebral canal (Fig. 2.24). There are two types of spina bifida. The commonest type is spina bifida occulta, in which there is a defect in the vertebral arch of LV or SI. This defect occurs in as many as 10% of individuals and results in failure of the posterior arch to fuse in the midline. Clinically, the patient is asymptomatic, although physical examination may reveal a tuft of hair over the spinous processes. | Anatomy_Gray. Table 2.2 Intermediate (respiratory) group of back muscles Table 2.3 Spinotransversales muscles Table 2.4 Erector spinae group of back muscles Table 2.5 Transversospinales group of back muscles Table 2.6 Segmental back muscles Table 2.7 Suboccipital group of back muscles In the clinic Spina bifida is a disorder in which the two sides of vertebral arches, usually in lower vertebrae, fail to fuse during development, resulting in an “open” vertebral canal (Fig. 2.24). There are two types of spina bifida. The commonest type is spina bifida occulta, in which there is a defect in the vertebral arch of LV or SI. This defect occurs in as many as 10% of individuals and results in failure of the posterior arch to fuse in the midline. Clinically, the patient is asymptomatic, although physical examination may reveal a tuft of hair over the spinous processes. |
Anatomy_Gray_231 | Anatomy_Gray | The more severe form of spina bifida involves complete failure of fusion of the posterior arch at the lumbosacral junction, with a large outpouching of the meninges. This may contain cerebrospinal fluid (a meningocele) or a portion of the spinal cord (a myelomeningocele). These abnormalities may result in a variety of neurological deficits, including problems with walking and bladder function. In the clinic Vertebroplasty is a relatively new technique in which the body of a vertebra can be filled with bone cement (typically methyl methacrylate). The indications for the technique include vertebral body collapse and pain from the vertebral body, which may be secondary to tumor infiltration. The procedure is most commonly performed for osteoporotic wedge fractures, which are a considerable cause of morbidity and pain in older patients. | Anatomy_Gray. The more severe form of spina bifida involves complete failure of fusion of the posterior arch at the lumbosacral junction, with a large outpouching of the meninges. This may contain cerebrospinal fluid (a meningocele) or a portion of the spinal cord (a myelomeningocele). These abnormalities may result in a variety of neurological deficits, including problems with walking and bladder function. In the clinic Vertebroplasty is a relatively new technique in which the body of a vertebra can be filled with bone cement (typically methyl methacrylate). The indications for the technique include vertebral body collapse and pain from the vertebral body, which may be secondary to tumor infiltration. The procedure is most commonly performed for osteoporotic wedge fractures, which are a considerable cause of morbidity and pain in older patients. |
Anatomy_Gray_232 | Anatomy_Gray | Osteoporotic wedge fractures (Fig. 2.25) typically occur in the thoracolumbar region, and the approach to performing vertebroplasty is novel and relatively straightforward. The procedure is performed under sedation or light general anesthetic. Using X-ray guidance the pedicle is identified on the anteroposterior image. A metal cannula is placed through the pedicle into the vertebral body. Liquid bone cement is injected via the cannula into the vertebral body (Fig. 2.26). The function of the bone cement is two-fold. First, it increases the strength of the vertebral body and prevents further loss of height. Furthermore, as the bone cement sets, there is a degree of heat generated that is believed to disrupt pain nerve endings. Kyphoplasty is a similar technique that aims to restore some or all of the lost vertebral body height from the wedge fracture by injecting liquid bone cement into the vertebral body. In the clinic | Anatomy_Gray. Osteoporotic wedge fractures (Fig. 2.25) typically occur in the thoracolumbar region, and the approach to performing vertebroplasty is novel and relatively straightforward. The procedure is performed under sedation or light general anesthetic. Using X-ray guidance the pedicle is identified on the anteroposterior image. A metal cannula is placed through the pedicle into the vertebral body. Liquid bone cement is injected via the cannula into the vertebral body (Fig. 2.26). The function of the bone cement is two-fold. First, it increases the strength of the vertebral body and prevents further loss of height. Furthermore, as the bone cement sets, there is a degree of heat generated that is believed to disrupt pain nerve endings. Kyphoplasty is a similar technique that aims to restore some or all of the lost vertebral body height from the wedge fracture by injecting liquid bone cement into the vertebral body. In the clinic |
Anatomy_Gray_233 | Anatomy_Gray | In the clinic Scoliosis is an abnormal lateral curvature of the vertebral column (Fig. 2.27). A true scoliosis involves not only the curvature (rightor left-sided) but also a rotational element of one vertebra upon another. The commonest types of scoliosis are those for which we have little understanding about how or why they occur and are termed idiopathic scoliosis. It is thought that there is some initial axial rotation of the vertebrae, which then alters the locations of the mechanical compressive and distractive forces applied through the vertebral growth plates, leading to changes in speed of bone growth and ultimately changes to spinal curvature. These are never present at birth and tend to occur in either the infantile, juvenile, or adolescent age groups. The vertebral bodies and posterior elements (pedicles and laminae) are normal in these patients. | Anatomy_Gray. In the clinic Scoliosis is an abnormal lateral curvature of the vertebral column (Fig. 2.27). A true scoliosis involves not only the curvature (rightor left-sided) but also a rotational element of one vertebra upon another. The commonest types of scoliosis are those for which we have little understanding about how or why they occur and are termed idiopathic scoliosis. It is thought that there is some initial axial rotation of the vertebrae, which then alters the locations of the mechanical compressive and distractive forces applied through the vertebral growth plates, leading to changes in speed of bone growth and ultimately changes to spinal curvature. These are never present at birth and tend to occur in either the infantile, juvenile, or adolescent age groups. The vertebral bodies and posterior elements (pedicles and laminae) are normal in these patients. |
Anatomy_Gray_234 | Anatomy_Gray | When a scoliosis is present from birth (congenital scoliosis) it is usually associated with other developmental abnormalities. In these patients, there is a strong association with other abnormalities of the chest wall, genitourinary tract, and heart disease. This group of patients needs careful evaluation by many specialists. A rare but important group of scoliosis is that in which the muscle is abnormal. Muscular dystrophy is the commonest example. The abnormal muscle does not retain the normal alignment of the vertebral column, and curvature develops as a result. A muscle biopsy is needed to make the diagnosis. Other disorders that can produce scoliosis include bone tumors, spinal cord tumors, and localized disc protrusions. In the clinic | Anatomy_Gray. When a scoliosis is present from birth (congenital scoliosis) it is usually associated with other developmental abnormalities. In these patients, there is a strong association with other abnormalities of the chest wall, genitourinary tract, and heart disease. This group of patients needs careful evaluation by many specialists. A rare but important group of scoliosis is that in which the muscle is abnormal. Muscular dystrophy is the commonest example. The abnormal muscle does not retain the normal alignment of the vertebral column, and curvature develops as a result. A muscle biopsy is needed to make the diagnosis. Other disorders that can produce scoliosis include bone tumors, spinal cord tumors, and localized disc protrusions. In the clinic |
Anatomy_Gray_235 | Anatomy_Gray | Other disorders that can produce scoliosis include bone tumors, spinal cord tumors, and localized disc protrusions. In the clinic Kyphosis is abnormal curvature of the vertebral column in the thoracic region, producing a “hunchback” deformity. This condition occurs in certain disease states, the most dramatic of which is usually secondary to tuberculosis infection of a thoracic vertebral body, where the kyphosis becomes angulated at the site of the lesion. This produces the gibbus deformity, a deformity that was prevalent before the use of antituberculous medication (Fig. 2.28). In the clinic Lordosis is abnormal curvature of the vertebral column in the lumbar region, producing a swayback deformity. In the clinic | Anatomy_Gray. Other disorders that can produce scoliosis include bone tumors, spinal cord tumors, and localized disc protrusions. In the clinic Kyphosis is abnormal curvature of the vertebral column in the thoracic region, producing a “hunchback” deformity. This condition occurs in certain disease states, the most dramatic of which is usually secondary to tuberculosis infection of a thoracic vertebral body, where the kyphosis becomes angulated at the site of the lesion. This produces the gibbus deformity, a deformity that was prevalent before the use of antituberculous medication (Fig. 2.28). In the clinic Lordosis is abnormal curvature of the vertebral column in the lumbar region, producing a swayback deformity. In the clinic |
Anatomy_Gray_236 | Anatomy_Gray | In the clinic Lordosis is abnormal curvature of the vertebral column in the lumbar region, producing a swayback deformity. In the clinic There are usually seven cervical vertebrae, although in certain diseases these may be fused. Fusion of cervical vertebrae (Fig. 2.29A) can be associated with other abnormalities, for example Klippel-Feil syndrome, in which there is fusion of vertebrae CI and CII or CV and CVI, and may be associated with a high-riding abnormalities. Variations in the number of thoracic vertebrae also are well described. | Anatomy_Gray. In the clinic Lordosis is abnormal curvature of the vertebral column in the lumbar region, producing a swayback deformity. In the clinic There are usually seven cervical vertebrae, although in certain diseases these may be fused. Fusion of cervical vertebrae (Fig. 2.29A) can be associated with other abnormalities, for example Klippel-Feil syndrome, in which there is fusion of vertebrae CI and CII or CV and CVI, and may be associated with a high-riding abnormalities. Variations in the number of thoracic vertebrae also are well described. |
Anatomy_Gray_237 | Anatomy_Gray | Variations in the number of thoracic vertebrae also are well described. One of the commonest abnormalities in the lumbar vertebrae is a partial fusion of vertebra LV with the sacrum (sacralization of the lumbar vertebra). Partial separation of vertebra SI from the sacrum (lumbarization of first sacral vertebra) may also occur (Fig. 2.29B). The LV vertebra can usually be identified by the iliolumbar ligament, which is a band of connective tissue that runs from the tip of the transverse process of LV to the iliac crest bilaterally (Fig. 2.29C). A hemivertebra occurs when a vertebra develops only on one side (Fig. 2.29B). In the clinic The vertebrae and cancer | Anatomy_Gray. Variations in the number of thoracic vertebrae also are well described. One of the commonest abnormalities in the lumbar vertebrae is a partial fusion of vertebra LV with the sacrum (sacralization of the lumbar vertebra). Partial separation of vertebra SI from the sacrum (lumbarization of first sacral vertebra) may also occur (Fig. 2.29B). The LV vertebra can usually be identified by the iliolumbar ligament, which is a band of connective tissue that runs from the tip of the transverse process of LV to the iliac crest bilaterally (Fig. 2.29C). A hemivertebra occurs when a vertebra develops only on one side (Fig. 2.29B). In the clinic The vertebrae and cancer |
Anatomy_Gray_238 | Anatomy_Gray | A hemivertebra occurs when a vertebra develops only on one side (Fig. 2.29B). In the clinic The vertebrae and cancer The vertebrae are common sites for metastatic disease (secondary spread of cancer cells). When cancer cells grow within the vertebral bodies and the posterior elements, they interrupt normal bone cell turnover, leading to either bone destruction or formation and destroying the mechanical properties of the bone. A minor injury may therefore lead to vertebral collapse (Fig. 2.30A). Cancer cells have a much higher glucose metabolism compared with normal adjacent bone cells. These metastatic cancer cells can therefore be detected by administering radioisotope-labeled glucose to a patient and then tracing where the labeled glucose has been metabolized (Fig. 2.30B). Importantly, vertebrae that contain extensive metastatic disease may extrude fragments of tumor into the vertebral canal, compressing nerves and the spinal cord. In the clinic | Anatomy_Gray. A hemivertebra occurs when a vertebra develops only on one side (Fig. 2.29B). In the clinic The vertebrae and cancer The vertebrae are common sites for metastatic disease (secondary spread of cancer cells). When cancer cells grow within the vertebral bodies and the posterior elements, they interrupt normal bone cell turnover, leading to either bone destruction or formation and destroying the mechanical properties of the bone. A minor injury may therefore lead to vertebral collapse (Fig. 2.30A). Cancer cells have a much higher glucose metabolism compared with normal adjacent bone cells. These metastatic cancer cells can therefore be detected by administering radioisotope-labeled glucose to a patient and then tracing where the labeled glucose has been metabolized (Fig. 2.30B). Importantly, vertebrae that contain extensive metastatic disease may extrude fragments of tumor into the vertebral canal, compressing nerves and the spinal cord. In the clinic |
Anatomy_Gray_239 | Anatomy_Gray | In the clinic Osteoporosis is a pathophysiologic condition in which bone quality is normal but the quantity of bone is deficient. It is a metabolic bone disorder that commonly occurs in women in their 50s and 60s and in men in their 70s. Many factors influence the development of osteoporosis, including genetic predetermination, level of activity and nutritional status, and, in particular, estrogen levels in women. Typical complications of osteoporosis include “crush” vertebral body fractures, distal fractures of the radius, and hip fractures. With increasing age and poor-quality bone, patients are more susceptible to fracture. Healing tends to be impaired in these elderly patients, who consequently require long hospital stays and prolonged rehabilitation. | Anatomy_Gray. In the clinic Osteoporosis is a pathophysiologic condition in which bone quality is normal but the quantity of bone is deficient. It is a metabolic bone disorder that commonly occurs in women in their 50s and 60s and in men in their 70s. Many factors influence the development of osteoporosis, including genetic predetermination, level of activity and nutritional status, and, in particular, estrogen levels in women. Typical complications of osteoporosis include “crush” vertebral body fractures, distal fractures of the radius, and hip fractures. With increasing age and poor-quality bone, patients are more susceptible to fracture. Healing tends to be impaired in these elderly patients, who consequently require long hospital stays and prolonged rehabilitation. |
Anatomy_Gray_240 | Anatomy_Gray | Patients likely to develop osteoporosis can be identified by dual-photon X-ray absorptiometry (DXA) scanning. Low-dose X-rays are passed through the bone, and by counting the number of photons detected and knowing the dose given, the number of X-rays absorbed by the bone can be calculated. The amount of X-ray absorption can be directly correlated with the bone mass, and this can be used to predict whether a patient is at risk for osteoporotic fractures. In the clinic Back pain is an extremely common disorder. It can be related to mechanical problems or to disc protrusion impinging on a nerve. In cases involving discs, it may be necessary to operate and remove the disc that is pressing on the nerve. | Anatomy_Gray. Patients likely to develop osteoporosis can be identified by dual-photon X-ray absorptiometry (DXA) scanning. Low-dose X-rays are passed through the bone, and by counting the number of photons detected and knowing the dose given, the number of X-rays absorbed by the bone can be calculated. The amount of X-ray absorption can be directly correlated with the bone mass, and this can be used to predict whether a patient is at risk for osteoporotic fractures. In the clinic Back pain is an extremely common disorder. It can be related to mechanical problems or to disc protrusion impinging on a nerve. In cases involving discs, it may be necessary to operate and remove the disc that is pressing on the nerve. |
Anatomy_Gray_241 | Anatomy_Gray | Not infrequently, patients complain of pain and no immediate cause is found; the pain is therefore attributed to mechanical discomfort, which may be caused by degenerative disease. One of the treatments is to pass a needle into the facet joint and inject it with local anesthetic and corticosteroid. In the clinic Herniation of intervertebral discs | Anatomy_Gray. Not infrequently, patients complain of pain and no immediate cause is found; the pain is therefore attributed to mechanical discomfort, which may be caused by degenerative disease. One of the treatments is to pass a needle into the facet joint and inject it with local anesthetic and corticosteroid. In the clinic Herniation of intervertebral discs |
Anatomy_Gray_242 | Anatomy_Gray | In the clinic Herniation of intervertebral discs The discs between the vertebrae are made up of a central portion (the nucleus pulposus) and a complex series of fibrous rings (anulus fibrosus). A tear can occur within the anulus fibrosus through which the material of the nucleus pulposus can track. After a period of time, this material may track into the vertebral canal or into the intervertebral foramen to impinge on neural structures (Fig. 2.34). This is a common cause of back pain. A disc may protrude posteriorly to directly impinge on the cord or the roots of the lumbar nerves, depending on the level, or may protrude posterolaterally adjacent to the pedicle and impinge on the descending root. In cervical regions of the vertebral column, cervical disc protrusions often become ossified and are termed disc osteophyte bars. In the clinic | Anatomy_Gray. In the clinic Herniation of intervertebral discs The discs between the vertebrae are made up of a central portion (the nucleus pulposus) and a complex series of fibrous rings (anulus fibrosus). A tear can occur within the anulus fibrosus through which the material of the nucleus pulposus can track. After a period of time, this material may track into the vertebral canal or into the intervertebral foramen to impinge on neural structures (Fig. 2.34). This is a common cause of back pain. A disc may protrude posteriorly to directly impinge on the cord or the roots of the lumbar nerves, depending on the level, or may protrude posterolaterally adjacent to the pedicle and impinge on the descending root. In cervical regions of the vertebral column, cervical disc protrusions often become ossified and are termed disc osteophyte bars. In the clinic |
Anatomy_Gray_243 | Anatomy_Gray | In cervical regions of the vertebral column, cervical disc protrusions often become ossified and are termed disc osteophyte bars. In the clinic Some diseases have a predilection for synovial joints rather than symphyses. A typical example is rheumatoid arthritis, which primarily affects synovial joints and synovial bursae, resulting in destruction of the joint and its lining. Symphyses are usually preserved. In the clinic The ligamenta flava are important structures associated with the vertebral canal (Fig. 2.39). In degenerative conditions of the vertebral column, the ligamenta flava may hypertrophy. This is often associated with hypertrophy and arthritic change of the zygapophysial joints. In combination, zygapophysial joint hypertrophy, ligamenta flava hypertrophy, and a mild disc protrusion can reduce the dimensions of the vertebral canal, producing the syndrome of spinal stenosis. In the clinic | Anatomy_Gray. In cervical regions of the vertebral column, cervical disc protrusions often become ossified and are termed disc osteophyte bars. In the clinic Some diseases have a predilection for synovial joints rather than symphyses. A typical example is rheumatoid arthritis, which primarily affects synovial joints and synovial bursae, resulting in destruction of the joint and its lining. Symphyses are usually preserved. In the clinic The ligamenta flava are important structures associated with the vertebral canal (Fig. 2.39). In degenerative conditions of the vertebral column, the ligamenta flava may hypertrophy. This is often associated with hypertrophy and arthritic change of the zygapophysial joints. In combination, zygapophysial joint hypertrophy, ligamenta flava hypertrophy, and a mild disc protrusion can reduce the dimensions of the vertebral canal, producing the syndrome of spinal stenosis. In the clinic |
Anatomy_Gray_244 | Anatomy_Gray | In the clinic Vertebral fractures can occur anywhere along the vertebral column. In most instances, the fracture will heal under appropriate circumstances. At the time of injury, it is not the fracture itself but related damage to the contents of the vertebral canal and the surrounding tissues that determines the severity of the patient’s condition. Vertebral column stability is divided into three arbitrary clinical “columns”: the anterior column consists of the vertebral bodies and the anterior longitudinal ligament; the middle column comprises the vertebral body and the posterior longitudinal ligament; and the posterior column is made up of the ligamenta flava, interspinous ligaments, supraspinous ligaments, and the ligamentum nuchae in the cervical vertebral column. | Anatomy_Gray. In the clinic Vertebral fractures can occur anywhere along the vertebral column. In most instances, the fracture will heal under appropriate circumstances. At the time of injury, it is not the fracture itself but related damage to the contents of the vertebral canal and the surrounding tissues that determines the severity of the patient’s condition. Vertebral column stability is divided into three arbitrary clinical “columns”: the anterior column consists of the vertebral bodies and the anterior longitudinal ligament; the middle column comprises the vertebral body and the posterior longitudinal ligament; and the posterior column is made up of the ligamenta flava, interspinous ligaments, supraspinous ligaments, and the ligamentum nuchae in the cervical vertebral column. |
Anatomy_Gray_245 | Anatomy_Gray | Destruction of one of the clinical columns is usually a stable injury requiring little more than rest and appropriate analgesia. Disruption of two columns is highly likely to be unstable and requires fixation and immobilization. A three-column spinal injury usually results in a significant neurological event and requires fixation to prevent further extension of the neurological defect and to create vertebral column stability. At the craniocervical junction, a complex series of ligaments create stability. If the traumatic incident disrupts craniocervical stability, the chances of a significant spinal cord injury are extremely high. The consequences are quadriplegia. In addition, respiratory function may be compromised by paralysis of the phrenic nerve (which arises from spinal nerves C3 to C5), and severe hypotension (low blood pressure) may result from central disruption of the sympathetic part of the autonomic division of the nervous system. | Anatomy_Gray. Destruction of one of the clinical columns is usually a stable injury requiring little more than rest and appropriate analgesia. Disruption of two columns is highly likely to be unstable and requires fixation and immobilization. A three-column spinal injury usually results in a significant neurological event and requires fixation to prevent further extension of the neurological defect and to create vertebral column stability. At the craniocervical junction, a complex series of ligaments create stability. If the traumatic incident disrupts craniocervical stability, the chances of a significant spinal cord injury are extremely high. The consequences are quadriplegia. In addition, respiratory function may be compromised by paralysis of the phrenic nerve (which arises from spinal nerves C3 to C5), and severe hypotension (low blood pressure) may result from central disruption of the sympathetic part of the autonomic division of the nervous system. |
Anatomy_Gray_246 | Anatomy_Gray | Mid and lower cervical vertebral column disruption may produce a range of complex neurological problems involving the upper and lower limbs, although below the level of C5, respiratory function is unlikely to be compromised. Lumbar vertebral column injuries are rare. When they occur, they usually involve significant force. Knowing that a significant force is required to fracture a vertebra, one must assess the abdominal organs and the rest of the axial skeleton for further fractures and visceral rupture. Vertebral injuries may also involve the soft tissues and supporting structures between the vertebrae. Typical examples of this are the unifacetal and bifacetal cervical vertebral dislocations that occur in hyperflexion injuries. The pars interarticularis is a clinical term to describe the specific region of a vertebra between the superior and inferior facet (zygapophysial) joints (Fig. 2.40A). This region is susceptible to trauma, especially in athletes. | Anatomy_Gray. Mid and lower cervical vertebral column disruption may produce a range of complex neurological problems involving the upper and lower limbs, although below the level of C5, respiratory function is unlikely to be compromised. Lumbar vertebral column injuries are rare. When they occur, they usually involve significant force. Knowing that a significant force is required to fracture a vertebra, one must assess the abdominal organs and the rest of the axial skeleton for further fractures and visceral rupture. Vertebral injuries may also involve the soft tissues and supporting structures between the vertebrae. Typical examples of this are the unifacetal and bifacetal cervical vertebral dislocations that occur in hyperflexion injuries. The pars interarticularis is a clinical term to describe the specific region of a vertebra between the superior and inferior facet (zygapophysial) joints (Fig. 2.40A). This region is susceptible to trauma, especially in athletes. |
Anatomy_Gray_247 | Anatomy_Gray | If a fracture occurs around the pars interarticularis, the vertebral body may slip anteriorly and compress the vertebral canal. The most common sites for pars interarticularis fractures are the LIV and LV levels (Fig. 2.40B,C). (Clinicians often refer to parts of the back in shorthand terms that are not strictly anatomical; for example, facet joints and apophyseal joints are terms used instead of zygapophysial joints, and spinal column is used instead of vertebral column.) It is possible for a vertebra to slip anteriorly upon its inferior counterpart without a pars interarticularis fracture. Usually this is related to abnormal anatomy of the facet joints, facet joint degenerative change. This disorder is termed spondylolisthesis. In the clinic Surgical procedures on the back | Anatomy_Gray. If a fracture occurs around the pars interarticularis, the vertebral body may slip anteriorly and compress the vertebral canal. The most common sites for pars interarticularis fractures are the LIV and LV levels (Fig. 2.40B,C). (Clinicians often refer to parts of the back in shorthand terms that are not strictly anatomical; for example, facet joints and apophyseal joints are terms used instead of zygapophysial joints, and spinal column is used instead of vertebral column.) It is possible for a vertebra to slip anteriorly upon its inferior counterpart without a pars interarticularis fracture. Usually this is related to abnormal anatomy of the facet joints, facet joint degenerative change. This disorder is termed spondylolisthesis. In the clinic Surgical procedures on the back |
Anatomy_Gray_248 | Anatomy_Gray | In the clinic Surgical procedures on the back A prolapsed intervertebral disc may impinge upon the meningeal (thecal) sac, cord, and most commonly the nerve root, producing symptoms attributable to that level. In some instances the disc protrusion will undergo a degree of involution that may allow symptoms to resolve without intervention. In some instances pain, loss of function, and failure to resolve may require surgery to remove the disc protrusion. | Anatomy_Gray. In the clinic Surgical procedures on the back A prolapsed intervertebral disc may impinge upon the meningeal (thecal) sac, cord, and most commonly the nerve root, producing symptoms attributable to that level. In some instances the disc protrusion will undergo a degree of involution that may allow symptoms to resolve without intervention. In some instances pain, loss of function, and failure to resolve may require surgery to remove the disc protrusion. |
Anatomy_Gray_249 | Anatomy_Gray | It is of the utmost importance that the level of the disc protrusion is identified before surgery. This may require MRI scanning and on-table fluoroscopy to prevent operating on the wrong level. A midline approach to the right or to the left of the spinous processes will depend upon the most prominent site of the disc bulge. In some instances removal of the lamina will increase the potential space and may relieve symptoms. Some surgeons perform a small fenestration (windowing) within the ligamentum flavum. This provides access to the canal. The meningeal sac and its contents are gently retracted, exposing the nerve root and the offending disc. The disc is dissected free, removing its effect on the nerve root and the canal. | Anatomy_Gray. It is of the utmost importance that the level of the disc protrusion is identified before surgery. This may require MRI scanning and on-table fluoroscopy to prevent operating on the wrong level. A midline approach to the right or to the left of the spinous processes will depend upon the most prominent site of the disc bulge. In some instances removal of the lamina will increase the potential space and may relieve symptoms. Some surgeons perform a small fenestration (windowing) within the ligamentum flavum. This provides access to the canal. The meningeal sac and its contents are gently retracted, exposing the nerve root and the offending disc. The disc is dissected free, removing its effect on the nerve root and the canal. |
Anatomy_Gray_250 | Anatomy_Gray | Spinal fusion is performed when it is necessary to fuse one vertebra with the corresponding superior or inferior vertebra, and in some instances multilevel fusion may be necessary. Indications are varied, though they include stabilization after fracture, stabilization related to tumor infiltration, and stabilization when mechanical pain is produced either from the disc or from the posterior elements. There are a number of surgical methods in which a fusion can be performed, through either a posterior approach and fusing the posterior elements, an anterior approach by removal of the disc and either disc replacement or anterior fusion, or in some instances a 360° fusion where the posterior elements and the vertebral bodies are fused (Fig. 2.41A,B). In the clinic | Anatomy_Gray. Spinal fusion is performed when it is necessary to fuse one vertebra with the corresponding superior or inferior vertebra, and in some instances multilevel fusion may be necessary. Indications are varied, though they include stabilization after fracture, stabilization related to tumor infiltration, and stabilization when mechanical pain is produced either from the disc or from the posterior elements. There are a number of surgical methods in which a fusion can be performed, through either a posterior approach and fusing the posterior elements, an anterior approach by removal of the disc and either disc replacement or anterior fusion, or in some instances a 360° fusion where the posterior elements and the vertebral bodies are fused (Fig. 2.41A,B). In the clinic |
Anatomy_Gray_251 | Anatomy_Gray | In the clinic Weakness in the trapezius, caused by an interruption of the accessory nerve [XI], may appear as drooping of the shoulder, inability to raise the arm above the head because of impaired rotation of the scapula, or weakness in attempting to raise the shoulder (i.e., shrug the shoulder against resistance). A weakness in, or an inability to use, the latissimus dorsi, resulting from an injury to the thoracodorsal nerve, diminishes the capacity to pull the body upward while climbing or doing a pull-up. An injury to the dorsal scapular nerve, which innervates the rhomboids, may result in a lateral shift in the position of the scapula on the affected side (i.e., the normal position of the scapula is lost because of the affected muscle’s inability to prevent antagonistic muscles from pulling the scapula laterally). In the clinic | Anatomy_Gray. In the clinic Weakness in the trapezius, caused by an interruption of the accessory nerve [XI], may appear as drooping of the shoulder, inability to raise the arm above the head because of impaired rotation of the scapula, or weakness in attempting to raise the shoulder (i.e., shrug the shoulder against resistance). A weakness in, or an inability to use, the latissimus dorsi, resulting from an injury to the thoracodorsal nerve, diminishes the capacity to pull the body upward while climbing or doing a pull-up. An injury to the dorsal scapular nerve, which innervates the rhomboids, may result in a lateral shift in the position of the scapula on the affected side (i.e., the normal position of the scapula is lost because of the affected muscle’s inability to prevent antagonistic muscles from pulling the scapula laterally). In the clinic |
Anatomy_Gray_252 | Anatomy_Gray | In the clinic The intervertebral discs are poorly vascularized; however, infection within the bloodstream can spread to the discs from the terminal branches of the spinal arteries within the vertebral body endplates, which lie immediately adjacent to the discs (Fig. 2.57). Common sources of infection include the lungs and urinary tract. In the clinic Fractures of the atlas and axis | Anatomy_Gray. In the clinic The intervertebral discs are poorly vascularized; however, infection within the bloodstream can spread to the discs from the terminal branches of the spinal arteries within the vertebral body endplates, which lie immediately adjacent to the discs (Fig. 2.57). Common sources of infection include the lungs and urinary tract. In the clinic Fractures of the atlas and axis |
Anatomy_Gray_253 | Anatomy_Gray | In the clinic Fractures of the atlas and axis Fractures of vertebra CI (the atlas) and vertebra CII (the axis) can potentially lead to the worst types of spinal cord injury including death and paralysis due to injury of the brainstem, which contains the cardiac and respiratory centers. The atlas is a closed ring with no vertebral body. Axial-loading injuries, such as hitting the head while diving into shallow water or hitting the head on the roof of a car in a motor vehicle accident, can cause a “burst” type of fracture, where the ring breaks at more than one site (Fig. 2.58). The British neurosurgeon, Geoffrey Jefferson, first described this fracture pattern in 1920, so these types of fractures are often called Jefferson fractures. | Anatomy_Gray. In the clinic Fractures of the atlas and axis Fractures of vertebra CI (the atlas) and vertebra CII (the axis) can potentially lead to the worst types of spinal cord injury including death and paralysis due to injury of the brainstem, which contains the cardiac and respiratory centers. The atlas is a closed ring with no vertebral body. Axial-loading injuries, such as hitting the head while diving into shallow water or hitting the head on the roof of a car in a motor vehicle accident, can cause a “burst” type of fracture, where the ring breaks at more than one site (Fig. 2.58). The British neurosurgeon, Geoffrey Jefferson, first described this fracture pattern in 1920, so these types of fractures are often called Jefferson fractures. |
Anatomy_Gray_254 | Anatomy_Gray | Fractures of the axis usually occur due to severe hyperextension and flexion, which can result in fracture of the tip of the dens, base of the dens, or through the body of the atlas. In judicial hangings, there is hyperextension and distraction injury causing fracture through the atlas pedicles and spondylolisthesis of C2 on C3. This type of fracture is often called a hangman’s fracture. In many cases of upper neck injuries, even in the absence of fractures to the atlas or axis, there may be injury to the atlanto-axial ligaments, which can render the neck unstable and pose severe risk to the brainstem and upper spinal cord. In the clinic | Anatomy_Gray. Fractures of the axis usually occur due to severe hyperextension and flexion, which can result in fracture of the tip of the dens, base of the dens, or through the body of the atlas. In judicial hangings, there is hyperextension and distraction injury causing fracture through the atlas pedicles and spondylolisthesis of C2 on C3. This type of fracture is often called a hangman’s fracture. In many cases of upper neck injuries, even in the absence of fractures to the atlas or axis, there may be injury to the atlanto-axial ligaments, which can render the neck unstable and pose severe risk to the brainstem and upper spinal cord. In the clinic |
Anatomy_Gray_255 | Anatomy_Gray | In the clinic An injury to the spinal cord in the cervical portion of the vertebral column can lead to varying degrees of impairment of sensory and motor function (paralysis) in all 4 limbs, termed quadriplegia or tetraplegia. An injury in upper levels of the cervical vertebral column can result in death because of loss of innervation to the diaphragm. An injury to the spinal cord below the level of TI can lead to varying degrees of impairment in motor and sensory function (paralysis) in the lower limbs, termed paraplegia. In the clinic A lumbar tap (puncture) is carried out to obtain a sample of CSF for examination. In addition, passage of a needle or conduit into the subarachnoid space (CSF space) is used to inject antibiotics, chemotherapeutic agents, and anesthetics. | Anatomy_Gray. In the clinic An injury to the spinal cord in the cervical portion of the vertebral column can lead to varying degrees of impairment of sensory and motor function (paralysis) in all 4 limbs, termed quadriplegia or tetraplegia. An injury in upper levels of the cervical vertebral column can result in death because of loss of innervation to the diaphragm. An injury to the spinal cord below the level of TI can lead to varying degrees of impairment in motor and sensory function (paralysis) in the lower limbs, termed paraplegia. In the clinic A lumbar tap (puncture) is carried out to obtain a sample of CSF for examination. In addition, passage of a needle or conduit into the subarachnoid space (CSF space) is used to inject antibiotics, chemotherapeutic agents, and anesthetics. |
Anatomy_Gray_256 | Anatomy_Gray | The lumbar region is an ideal site to access the subarachnoid space because the spinal cord terminates around the level of the disc between vertebrae LI and LII in the adult. The subarachnoid space extends to the region of the lower border of the SII vertebra. There is therefore a large CSF-filled space containing lumbar and sacral nerve roots but no spinal cord. Depending on the clinician’s preference, the patient is placed in the lateral or prone position. A needle is passed in the midline in between the spinous processes into the extradural space. Further advancement punctures the dura and arachnoid mater to enter the subarachnoid space. Most needles push the roots away from the tip without causing the patient any symptoms. Once the needle is in the subarachnoid space, fluid can be aspirated. In some situations, it is important to measure CSF pressure. | Anatomy_Gray. The lumbar region is an ideal site to access the subarachnoid space because the spinal cord terminates around the level of the disc between vertebrae LI and LII in the adult. The subarachnoid space extends to the region of the lower border of the SII vertebra. There is therefore a large CSF-filled space containing lumbar and sacral nerve roots but no spinal cord. Depending on the clinician’s preference, the patient is placed in the lateral or prone position. A needle is passed in the midline in between the spinous processes into the extradural space. Further advancement punctures the dura and arachnoid mater to enter the subarachnoid space. Most needles push the roots away from the tip without causing the patient any symptoms. Once the needle is in the subarachnoid space, fluid can be aspirated. In some situations, it is important to measure CSF pressure. |
Anatomy_Gray_257 | Anatomy_Gray | Local anesthetics can be injected into the extradural space or the subarachnoid space to anesthetize the sacral and lumbar nerve roots. Such anesthesia is useful for operations on the pelvis and the legs, which can then be carried out without the need for general anesthesia. When procedures are carried out, the patient must be in the erect position and not lying on his or her side or in the head-down position. If a patient lies on his or her side, the anesthesia is likely to be unilateral. If the patient is placed in the head-down position, the anesthetic can pass cranially and potentially depress respiration. | Anatomy_Gray. Local anesthetics can be injected into the extradural space or the subarachnoid space to anesthetize the sacral and lumbar nerve roots. Such anesthesia is useful for operations on the pelvis and the legs, which can then be carried out without the need for general anesthesia. When procedures are carried out, the patient must be in the erect position and not lying on his or her side or in the head-down position. If a patient lies on his or her side, the anesthesia is likely to be unilateral. If the patient is placed in the head-down position, the anesthetic can pass cranially and potentially depress respiration. |
Anatomy_Gray_258 | Anatomy_Gray | In some instances, anesthesiologists choose to carry out extradural anesthesia. A needle is placed through the skin, supraspinous ligament, interspinous ligament, and ligamenta flava into the areolar tissue and fat around the dura mater. Anesthetic agent is introduced and diffuses around the vertebral canal to anesthetize the exiting nerve roots and diffuse into the subarachnoid space. In the clinic Herpes zoster is the virus that produces chickenpox in children. In some patients the virus remains dormant in the cells of the spinal ganglia. Under certain circumstances, the virus becomes activated and travels along the neuronal bundles to the areas supplied by that nerve (the dermatome). A rash ensues, which is characteristically exquisitely painful. Importantly, this typical dermatomal distribution is characteristic of this disorder. In the clinic | Anatomy_Gray. In some instances, anesthesiologists choose to carry out extradural anesthesia. A needle is placed through the skin, supraspinous ligament, interspinous ligament, and ligamenta flava into the areolar tissue and fat around the dura mater. Anesthetic agent is introduced and diffuses around the vertebral canal to anesthetize the exiting nerve roots and diffuse into the subarachnoid space. In the clinic Herpes zoster is the virus that produces chickenpox in children. In some patients the virus remains dormant in the cells of the spinal ganglia. Under certain circumstances, the virus becomes activated and travels along the neuronal bundles to the areas supplied by that nerve (the dermatome). A rash ensues, which is characteristically exquisitely painful. Importantly, this typical dermatomal distribution is characteristic of this disorder. In the clinic |
Anatomy_Gray_259 | Anatomy_Gray | In the clinic Back pain is an extremely common condition affecting almost all individuals at some stage during their life. It is of key clinical importance to identify whether the back pain relates to the vertebral column and its attachments or relates to other structures. | Anatomy_Gray. In the clinic Back pain is an extremely common condition affecting almost all individuals at some stage during their life. It is of key clinical importance to identify whether the back pain relates to the vertebral column and its attachments or relates to other structures. |
Anatomy_Gray_260 | Anatomy_Gray | The failure to consider other potential structures that may produce back pain can lead to significant mortality and morbidity. Pain may refer to the back from a number of organs situated in the retroperitoneum. Pancreatic pain in particular refers to the back and may be associated with pancreatic cancer and pancreatitis. Renal pain, which may be produced by stones in the renal collecting system or renal tumors, also typically refers to the back. More often than not this is usually unilateral; however, it can produce central posterior back pain. Enlarged lymph nodes in the preand para-aortic region may produce central posterior back pain and may be a sign of solid tumor malignancy, infection, or Hodgkin’s lymphoma. An enlarging abdominal aorta (abdominal aortic aneurysm) may cause back pain as it enlarges without rupture. Therefore it is critical to think of this structure as a potential cause of back pain, because treatment will be lifesaving. Moreover, a ruptured abdominal aortic | Anatomy_Gray. The failure to consider other potential structures that may produce back pain can lead to significant mortality and morbidity. Pain may refer to the back from a number of organs situated in the retroperitoneum. Pancreatic pain in particular refers to the back and may be associated with pancreatic cancer and pancreatitis. Renal pain, which may be produced by stones in the renal collecting system or renal tumors, also typically refers to the back. More often than not this is usually unilateral; however, it can produce central posterior back pain. Enlarged lymph nodes in the preand para-aortic region may produce central posterior back pain and may be a sign of solid tumor malignancy, infection, or Hodgkin’s lymphoma. An enlarging abdominal aorta (abdominal aortic aneurysm) may cause back pain as it enlarges without rupture. Therefore it is critical to think of this structure as a potential cause of back pain, because treatment will be lifesaving. Moreover, a ruptured abdominal aortic |
Anatomy_Gray_261 | Anatomy_Gray | pain as it enlarges without rupture. Therefore it is critical to think of this structure as a potential cause of back pain, because treatment will be lifesaving. Moreover, a ruptured abdominal aortic aneurysm may also cause acute back pain in the first instance. | Anatomy_Gray. pain as it enlarges without rupture. Therefore it is critical to think of this structure as a potential cause of back pain, because treatment will be lifesaving. Moreover, a ruptured abdominal aortic aneurysm may also cause acute back pain in the first instance. |
Anatomy_Gray_262 | Anatomy_Gray | In all patients back pain requires careful assessment not only of the vertebral column but also of the chest and abdomen in order not to miss other important anatomical structures that may produce signs and symptoms radiating to the back. A 50-year-old man was brought to the emergency department with severe lower back pain that had started several days ago. In the past 24 hours he has had two episodes of fecal incontinence and inability to pass urine and now reports numbness and weakness in both his legs. The attending physician performed a physical examination and found that the man had reduced strength during knee extension and when dorsiflexing his feet and toes. He also had reduced reflexes in his knees and ankles, numbness in the perineal (saddle) region, as well as reduced anal sphincter tone. | Anatomy_Gray. In all patients back pain requires careful assessment not only of the vertebral column but also of the chest and abdomen in order not to miss other important anatomical structures that may produce signs and symptoms radiating to the back. A 50-year-old man was brought to the emergency department with severe lower back pain that had started several days ago. In the past 24 hours he has had two episodes of fecal incontinence and inability to pass urine and now reports numbness and weakness in both his legs. The attending physician performed a physical examination and found that the man had reduced strength during knee extension and when dorsiflexing his feet and toes. He also had reduced reflexes in his knees and ankles, numbness in the perineal (saddle) region, as well as reduced anal sphincter tone. |
Anatomy_Gray_263 | Anatomy_Gray | The patient’s symptoms and physical examination findings raised serious concern for compression of multiple lumbar and sacral nerve roots in the spine, affecting both motor and sensory pathways. His reduced power in extending his knees and reduced knee reflexes was suggestive of compression of the L4 nerve roots. His reduced ability to dorsiflex his feet and toes was suggestive of compression of the L5 nerve roots. His reduced ankle reflexes was suggestive of compression of the S1 and S2 nerve roots, and his perineal numbness was suggestive of compression of the S3, S4, and S5 nerve roots. A diagnosis of cauda equina syndrome was made, and the patient was transferred for an urgent MRI scan, which confirmed the presence of a severely herniating L2-3 disc compressing the cauda equina, giving rise to the cauda equina syndrome (Fig. 2.70). The patient underwent surgical decompression of the cauda equina and made a full recovery. | Anatomy_Gray. The patient’s symptoms and physical examination findings raised serious concern for compression of multiple lumbar and sacral nerve roots in the spine, affecting both motor and sensory pathways. His reduced power in extending his knees and reduced knee reflexes was suggestive of compression of the L4 nerve roots. His reduced ability to dorsiflex his feet and toes was suggestive of compression of the L5 nerve roots. His reduced ankle reflexes was suggestive of compression of the S1 and S2 nerve roots, and his perineal numbness was suggestive of compression of the S3, S4, and S5 nerve roots. A diagnosis of cauda equina syndrome was made, and the patient was transferred for an urgent MRI scan, which confirmed the presence of a severely herniating L2-3 disc compressing the cauda equina, giving rise to the cauda equina syndrome (Fig. 2.70). The patient underwent surgical decompression of the cauda equina and made a full recovery. |
Anatomy_Gray_264 | Anatomy_Gray | The collection of lumbar and sacral nerve roots beyond the conus medullaris has a horsetail-like appearance, from which it derives its name “cauda equina.” Compression of the cauda equina may be caused by a herniating disc (as in this case), fracture fragments following traumatic injury, tumor, abscess, or severe degenerative stenosis of the central canal. Cauda equina syndrome is classed as a surgical emergency to prevent permanent and irreversible damage to the compressed nerve roots. A 45-year-old man was involved in a serious car accident. On examination he had a severe injury to the cervical region of his vertebral column with damage to the spinal cord. In fact, his breathing became erratic and stopped. | Anatomy_Gray. The collection of lumbar and sacral nerve roots beyond the conus medullaris has a horsetail-like appearance, from which it derives its name “cauda equina.” Compression of the cauda equina may be caused by a herniating disc (as in this case), fracture fragments following traumatic injury, tumor, abscess, or severe degenerative stenosis of the central canal. Cauda equina syndrome is classed as a surgical emergency to prevent permanent and irreversible damage to the compressed nerve roots. A 45-year-old man was involved in a serious car accident. On examination he had a severe injury to the cervical region of his vertebral column with damage to the spinal cord. In fact, his breathing became erratic and stopped. |
Anatomy_Gray_265 | Anatomy_Gray | If the cervical spinal cord injury is above the level of C5, breathing is likely to stop. The phrenic nerve takes origin from C3, C4, and C5 and supplies the diaphragm. Breathing may not cease immediately if the lesion is just below C5, but does so as the cord becomes edematous and damage progresses superiorly. In addition, some respiratory and ventilatory exchange may occur by using neck muscles plus the sternocleidomastoid and trapezius muscles, which are innervated by the accessory nerve [XI]. The patient was unable to sense or move his upper and lower limbs. The patient has paralysis of the upper and lower limbs and is therefore quadriplegic. If breathing is unaffected, the lesion is below the level of C5 or at the level of C5. The nerve supply to the upper limbs is via the brachial plexus, which begins at the C5 level. The site of the spinal cord injury is at or above the C5 level. | Anatomy_Gray. If the cervical spinal cord injury is above the level of C5, breathing is likely to stop. The phrenic nerve takes origin from C3, C4, and C5 and supplies the diaphragm. Breathing may not cease immediately if the lesion is just below C5, but does so as the cord becomes edematous and damage progresses superiorly. In addition, some respiratory and ventilatory exchange may occur by using neck muscles plus the sternocleidomastoid and trapezius muscles, which are innervated by the accessory nerve [XI]. The patient was unable to sense or move his upper and lower limbs. The patient has paralysis of the upper and lower limbs and is therefore quadriplegic. If breathing is unaffected, the lesion is below the level of C5 or at the level of C5. The nerve supply to the upper limbs is via the brachial plexus, which begins at the C5 level. The site of the spinal cord injury is at or above the C5 level. |
Anatomy_Gray_266 | Anatomy_Gray | It is important to remember that although the cord has been transected in the cervical region, the cord below this level is intact. Reflex activity may therefore occur below the injury, but communication with the brain is lost. A 25-year-old woman complained of increasing lumbar back pain. Over the ensuing weeks she was noted to have an enlarging lump in the right groin, which was mildly tender to touch. On direct questioning, the patient also complained of a productive cough with sputum containing mucus and blood, and she had a mild temperature. The chest radiograph revealed a cavitating apical lung mass, which explains the pulmonary history. | Anatomy_Gray. It is important to remember that although the cord has been transected in the cervical region, the cord below this level is intact. Reflex activity may therefore occur below the injury, but communication with the brain is lost. A 25-year-old woman complained of increasing lumbar back pain. Over the ensuing weeks she was noted to have an enlarging lump in the right groin, which was mildly tender to touch. On direct questioning, the patient also complained of a productive cough with sputum containing mucus and blood, and she had a mild temperature. The chest radiograph revealed a cavitating apical lung mass, which explains the pulmonary history. |
Anatomy_Gray_267 | Anatomy_Gray | The chest radiograph revealed a cavitating apical lung mass, which explains the pulmonary history. Given the age of the patient a primary lung cancer is unlikely. The hemoptysis (coughing up blood in the sputum) and the rest of the history suggest the patient has a lung infection. Given the chest radiographic findings of a cavity in the apex of the lung, a diagnosis of tuberculosis (TB) was made. This was confirmed by bronchoscopy and aspiration of pus, which was cultured. | Anatomy_Gray. The chest radiograph revealed a cavitating apical lung mass, which explains the pulmonary history. Given the age of the patient a primary lung cancer is unlikely. The hemoptysis (coughing up blood in the sputum) and the rest of the history suggest the patient has a lung infection. Given the chest radiographic findings of a cavity in the apex of the lung, a diagnosis of tuberculosis (TB) was made. This was confirmed by bronchoscopy and aspiration of pus, which was cultured. |
Anatomy_Gray_268 | Anatomy_Gray | During the patient’s pulmonary infection, the tuberculous bacillus had spread via the blood to vertebra LI. The bone destruction began in the cancellous bone of the vertebral body close to the intervertebral discs. This disease progressed and eroded into the intervertebral disc, which became infected. The disc was destroyed, and the infected disc material extruded around the disc anteriorly and passed into the psoas muscle sheath. This is not an uncommon finding for a tuberculous infection of the lumbar portion of the vertebral column. As the infection progressed, the pus spread within the psoas muscle sheath beneath the inguinal ligament to produce a hard mass in the groin. This is a typical finding for a psoas abscess. Fortunately for the patient, there was no evidence of any damage within the vertebral canal. | Anatomy_Gray. During the patient’s pulmonary infection, the tuberculous bacillus had spread via the blood to vertebra LI. The bone destruction began in the cancellous bone of the vertebral body close to the intervertebral discs. This disease progressed and eroded into the intervertebral disc, which became infected. The disc was destroyed, and the infected disc material extruded around the disc anteriorly and passed into the psoas muscle sheath. This is not an uncommon finding for a tuberculous infection of the lumbar portion of the vertebral column. As the infection progressed, the pus spread within the psoas muscle sheath beneath the inguinal ligament to produce a hard mass in the groin. This is a typical finding for a psoas abscess. Fortunately for the patient, there was no evidence of any damage within the vertebral canal. |
Anatomy_Gray_269 | Anatomy_Gray | Fortunately for the patient, there was no evidence of any damage within the vertebral canal. The patient underwent a radiologically guided drainage of the psoas abscess and was treated for over 6 months with a long-term antibiotic regimen. She made an excellent recovery with no further symptoms, although the cavities within the lungs remain. It healed with sclerosis. A 72-year-old fit and healthy man was brought to the emergency department with severe back pain beginning at the level of the shoulder blades and extending to the midlumbar region. The pain was of relatively acute onset and was continuous. The patient was able to walk to the gurney as he entered the ambulance; however, at the emergency department the patient complained of inability to use both legs. | Anatomy_Gray. Fortunately for the patient, there was no evidence of any damage within the vertebral canal. The patient underwent a radiologically guided drainage of the psoas abscess and was treated for over 6 months with a long-term antibiotic regimen. She made an excellent recovery with no further symptoms, although the cavities within the lungs remain. It healed with sclerosis. A 72-year-old fit and healthy man was brought to the emergency department with severe back pain beginning at the level of the shoulder blades and extending to the midlumbar region. The pain was of relatively acute onset and was continuous. The patient was able to walk to the gurney as he entered the ambulance; however, at the emergency department the patient complained of inability to use both legs. |
Anatomy_Gray_270 | Anatomy_Gray | The attending physician examined the back thoroughly and found no significant abnormality. He noted that there was reduced sensation in both legs, and there was virtually no power in extensor or flexor groups. The patient was tachycardic, which was believed to be due to pain, and the blood pressure obtained in the ambulance measured 120/80 mm Hg. It was noted that the patient’s current blood pressure was 80/40 mm Hg; however, the patient did not complain of typical clinical symptoms of hypotension. On first inspection, it is difficult to “add up” these clinical symptoms and signs. In essence we have a progressive paraplegia associated with severe back pain and an anomaly in blood pressure measurements, which are not compatible with the clinical state of the patient. It was deduced that the blood pressure measurements were obtained in different arms, and both were reassessed. | Anatomy_Gray. The attending physician examined the back thoroughly and found no significant abnormality. He noted that there was reduced sensation in both legs, and there was virtually no power in extensor or flexor groups. The patient was tachycardic, which was believed to be due to pain, and the blood pressure obtained in the ambulance measured 120/80 mm Hg. It was noted that the patient’s current blood pressure was 80/40 mm Hg; however, the patient did not complain of typical clinical symptoms of hypotension. On first inspection, it is difficult to “add up” these clinical symptoms and signs. In essence we have a progressive paraplegia associated with severe back pain and an anomaly in blood pressure measurements, which are not compatible with the clinical state of the patient. It was deduced that the blood pressure measurements were obtained in different arms, and both were reassessed. |
Anatomy_Gray_271 | Anatomy_Gray | It was deduced that the blood pressure measurements were obtained in different arms, and both were reassessed. The blood pressure measurements were true. In the right arm the blood pressure measured 120/80 mm Hg and in the left arm the blood pressure measured 80/40 mm Hg. This would imply a deficiency of blood to the left arm. The patient was transferred from the emergency department to the CT scanner, and a scan was performed that included the chest, abdomen, and pelvis. | Anatomy_Gray. It was deduced that the blood pressure measurements were obtained in different arms, and both were reassessed. The blood pressure measurements were true. In the right arm the blood pressure measured 120/80 mm Hg and in the left arm the blood pressure measured 80/40 mm Hg. This would imply a deficiency of blood to the left arm. The patient was transferred from the emergency department to the CT scanner, and a scan was performed that included the chest, abdomen, and pelvis. |
Anatomy_Gray_272 | Anatomy_Gray | The CT scan demonstrated a dissecting thoracic aortic aneurysm. Aortic dissection occurs when the tunica intima and part of the tunica media of the wall of the aorta become separated from the remainder of the tunica media and the tunica adventitia of the aorta wall. This produces a false lumen. Blood passes not only in the true aortic lumen but also through a small hole into the wall of the aorta and into the false lumen. It often reenters the true aortic lumen inferiorly. This produces two channels through which blood may flow. The process of the aortic dissection produces considerable pain for the patient and is usually of rapid onset. Typically the pain is felt between the shoulder blades and radiating into the back, and although the pain is not from the back musculature or the vertebral column, careful consideration of structures other than the back should always be sought. | Anatomy_Gray. The CT scan demonstrated a dissecting thoracic aortic aneurysm. Aortic dissection occurs when the tunica intima and part of the tunica media of the wall of the aorta become separated from the remainder of the tunica media and the tunica adventitia of the aorta wall. This produces a false lumen. Blood passes not only in the true aortic lumen but also through a small hole into the wall of the aorta and into the false lumen. It often reenters the true aortic lumen inferiorly. This produces two channels through which blood may flow. The process of the aortic dissection produces considerable pain for the patient and is usually of rapid onset. Typically the pain is felt between the shoulder blades and radiating into the back, and although the pain is not from the back musculature or the vertebral column, careful consideration of structures other than the back should always be sought. |
Anatomy_Gray_273 | Anatomy_Gray | The difference in the blood pressure between the two arms indicates the level at which the dissection has begun. The “point of entry” is proximal to the left subclavian artery. At this level a small flap has been created, which limits the blood flow to the left upper limb, giving the low blood pressure recording. The brachiocephalic trunk has not been affected by the aortic dissection, and hence blood flow remains appropriate to the right upper limb. The paraplegia was caused by ischemia to the spinal cord. | Anatomy_Gray. The difference in the blood pressure between the two arms indicates the level at which the dissection has begun. The “point of entry” is proximal to the left subclavian artery. At this level a small flap has been created, which limits the blood flow to the left upper limb, giving the low blood pressure recording. The brachiocephalic trunk has not been affected by the aortic dissection, and hence blood flow remains appropriate to the right upper limb. The paraplegia was caused by ischemia to the spinal cord. |
Anatomy_Gray_274 | Anatomy_Gray | The paraplegia was caused by ischemia to the spinal cord. The blood supply to the spinal cord is from a single anterior spinal artery and two posterior spinal arteries. These arteries are fed via segmental spinal arteries at every vertebral level. There are a number of reinforcing arteries (segmental medullary arteries) along the length of the spinal cord—the largest of which is the artery of Adamkiewicz. This artery of Adamkiewicz, a segmental medullary artery, typically arises from the lower thoracic or upper lumbar region, and unfortunately during this patient’s aortic dissection, the origin of this vessel was disrupted. This produces acute spinal cord ischemia and has produced the paraplegia in the patient. Unfortunately, the dissection extended, the aorta ruptured, and the patient succumbed. | Anatomy_Gray. The paraplegia was caused by ischemia to the spinal cord. The blood supply to the spinal cord is from a single anterior spinal artery and two posterior spinal arteries. These arteries are fed via segmental spinal arteries at every vertebral level. There are a number of reinforcing arteries (segmental medullary arteries) along the length of the spinal cord—the largest of which is the artery of Adamkiewicz. This artery of Adamkiewicz, a segmental medullary artery, typically arises from the lower thoracic or upper lumbar region, and unfortunately during this patient’s aortic dissection, the origin of this vessel was disrupted. This produces acute spinal cord ischemia and has produced the paraplegia in the patient. Unfortunately, the dissection extended, the aorta ruptured, and the patient succumbed. |
Anatomy_Gray_275 | Anatomy_Gray | Unfortunately, the dissection extended, the aorta ruptured, and the patient succumbed. A 55-year-old woman came to her physician with sensory alteration in the right gluteal (buttock) region and in the intergluteal (natal) cleft. Examination also demonstrated low-grade weakness of the muscles of the foot and subtle weakness of the extensor hallucis longus, extensor digitorum longus, and fibularis tertius on the right. The patient also complained of some mild pain symptoms posteriorly in the right gluteal region. A lesion was postulated in the left sacrum. | Anatomy_Gray. Unfortunately, the dissection extended, the aorta ruptured, and the patient succumbed. A 55-year-old woman came to her physician with sensory alteration in the right gluteal (buttock) region and in the intergluteal (natal) cleft. Examination also demonstrated low-grade weakness of the muscles of the foot and subtle weakness of the extensor hallucis longus, extensor digitorum longus, and fibularis tertius on the right. The patient also complained of some mild pain symptoms posteriorly in the right gluteal region. A lesion was postulated in the left sacrum. |
Anatomy_Gray_276 | Anatomy_Gray | A lesion was postulated in the left sacrum. Pain in the right sacro-iliac region could easily be attributed to the sacro-iliac joint, which is often very sensitive to pain. The weakness of the intrinsic muscles of the foot and the extensor hallucis longus, extensor digitorum longus, and fibularis tertius muscles raises the possibility of an abnormality affecting the nerves exiting the sacrum and possibly the lumbosacral junction. The altered sensation around the gluteal region toward the anus would also support these anatomical localizing features. An X-ray was obtained of the pelvis. | Anatomy_Gray. A lesion was postulated in the left sacrum. Pain in the right sacro-iliac region could easily be attributed to the sacro-iliac joint, which is often very sensitive to pain. The weakness of the intrinsic muscles of the foot and the extensor hallucis longus, extensor digitorum longus, and fibularis tertius muscles raises the possibility of an abnormality affecting the nerves exiting the sacrum and possibly the lumbosacral junction. The altered sensation around the gluteal region toward the anus would also support these anatomical localizing features. An X-ray was obtained of the pelvis. |
Anatomy_Gray_277 | Anatomy_Gray | An X-ray was obtained of the pelvis. The X-ray appeared on first inspection unremarkable. However, the patient underwent further investigation, including CT and MRI, which demonstrated a large destructive lesion involving the whole of the left sacrum extending into the anterior sacral foramina at the S1, S2, and S3 levels. Interestingly, plain radiographs of the sacrum may often appear normal on first inspection, and further imaging should always be sought in patients with a suspected sacral abnormality. The lesion was expansile and lytic. Most bony metastases are typically nonexpansile. They may well erode the bone, producing lytic type of lesions, or may become very sclerotic (prostate metastases and breast metastases). From time to time we see a mixed pattern of lytic and sclerotic. | Anatomy_Gray. An X-ray was obtained of the pelvis. The X-ray appeared on first inspection unremarkable. However, the patient underwent further investigation, including CT and MRI, which demonstrated a large destructive lesion involving the whole of the left sacrum extending into the anterior sacral foramina at the S1, S2, and S3 levels. Interestingly, plain radiographs of the sacrum may often appear normal on first inspection, and further imaging should always be sought in patients with a suspected sacral abnormality. The lesion was expansile and lytic. Most bony metastases are typically nonexpansile. They may well erode the bone, producing lytic type of lesions, or may become very sclerotic (prostate metastases and breast metastases). From time to time we see a mixed pattern of lytic and sclerotic. |
Anatomy_Gray_278 | Anatomy_Gray | There are a number of uncommon instances in which certain metastases are expansile and lytic. These typically occur in renal metastases and may be seen in multiple myeloma. The anatomical importance of these specific tumors is that they often expand and impinge upon other structures. The expansile nature of this patient’s tumor within the sacrum was the cause for compression of the sacral nerve roots, producing her symptoms. The patient underwent a course of radiotherapy, had the renal tumor excised, and is currently undergoing a course of chemoimmunotherapy. 122.e1 122.e2 Conceptual Overview • Relationship to Other Regions Fig. 2.20, cont’d Fig. 2.20, cont’d In the clinic—cont’d Fig. 2.55, cont’d Fig. 2.68, cont’d Fig. 2.69, cont’d | Anatomy_Gray. There are a number of uncommon instances in which certain metastases are expansile and lytic. These typically occur in renal metastases and may be seen in multiple myeloma. The anatomical importance of these specific tumors is that they often expand and impinge upon other structures. The expansile nature of this patient’s tumor within the sacrum was the cause for compression of the sacral nerve roots, producing her symptoms. The patient underwent a course of radiotherapy, had the renal tumor excised, and is currently undergoing a course of chemoimmunotherapy. 122.e1 122.e2 Conceptual Overview • Relationship to Other Regions Fig. 2.20, cont’d Fig. 2.20, cont’d In the clinic—cont’d Fig. 2.55, cont’d Fig. 2.68, cont’d Fig. 2.69, cont’d |
Anatomy_Gray_279 | Anatomy_Gray | 122.e1 122.e2 Conceptual Overview • Relationship to Other Regions Fig. 2.20, cont’d Fig. 2.20, cont’d In the clinic—cont’d Fig. 2.55, cont’d Fig. 2.68, cont’d Fig. 2.69, cont’d The thorax is an irregularly shaped cylinder with a narrow opening (superior thoracic aperture) superiorly and a relatively large opening (inferior thoracic aperture) inferiorly (Fig. 3.1). The superior thoracic aperture is open, allowing continuity with the neck; the inferior thoracic aperture is closed by the diaphragm. The musculoskeletal wall of the thorax is flexible and consists of segmentally arranged vertebrae, ribs, and muscles and the sternum. The thoracic cavity enclosed by the thoracic wall and the diaphragm is subdivided into three major compartments: a left and a right pleural cavity, each surrounding a lung, and the mediastinum. | Anatomy_Gray. 122.e1 122.e2 Conceptual Overview • Relationship to Other Regions Fig. 2.20, cont’d Fig. 2.20, cont’d In the clinic—cont’d Fig. 2.55, cont’d Fig. 2.68, cont’d Fig. 2.69, cont’d The thorax is an irregularly shaped cylinder with a narrow opening (superior thoracic aperture) superiorly and a relatively large opening (inferior thoracic aperture) inferiorly (Fig. 3.1). The superior thoracic aperture is open, allowing continuity with the neck; the inferior thoracic aperture is closed by the diaphragm. The musculoskeletal wall of the thorax is flexible and consists of segmentally arranged vertebrae, ribs, and muscles and the sternum. The thoracic cavity enclosed by the thoracic wall and the diaphragm is subdivided into three major compartments: a left and a right pleural cavity, each surrounding a lung, and the mediastinum. |
Anatomy_Gray_280 | Anatomy_Gray | The thoracic cavity enclosed by the thoracic wall and the diaphragm is subdivided into three major compartments: a left and a right pleural cavity, each surrounding a lung, and the mediastinum. The mediastinum is a thick, flexible soft tissue partition oriented longitudinally in a median sagittal position. It contains the heart, esophagus, trachea, major nerves, and major systemic blood vessels. The pleural cavities are completely separated from each other by the mediastinum. Therefore abnormal events in one pleural cavity do not necessarily affect the other cavity. This also means that the mediastinum can be entered surgically without opening the pleural cavities. | Anatomy_Gray. The thoracic cavity enclosed by the thoracic wall and the diaphragm is subdivided into three major compartments: a left and a right pleural cavity, each surrounding a lung, and the mediastinum. The mediastinum is a thick, flexible soft tissue partition oriented longitudinally in a median sagittal position. It contains the heart, esophagus, trachea, major nerves, and major systemic blood vessels. The pleural cavities are completely separated from each other by the mediastinum. Therefore abnormal events in one pleural cavity do not necessarily affect the other cavity. This also means that the mediastinum can be entered surgically without opening the pleural cavities. |
Anatomy_Gray_281 | Anatomy_Gray | Another important feature of the pleural cavities is that they extend above the level of rib I. The apex of each lung actually extends into the root of the neck. As a consequence, abnormal events in the root of the neck can involve the adjacent pleura and lung, and events in the adjacent pleura and lung can involve the root of the neck. One of the most important functions of the thorax is breathing. The thorax not only contains the lungs but also provides the machinery necessary—the diaphragm, thoracic wall, and ribs—for effectively moving air into and out of the lungs. Up and down movements of the diaphragm and changes in the lateral and anterior dimensions of the thoracic wall, caused by movements of the ribs, alter the volume of the thoracic cavity and are key elements in breathing. Protection of vital organs | Anatomy_Gray. Another important feature of the pleural cavities is that they extend above the level of rib I. The apex of each lung actually extends into the root of the neck. As a consequence, abnormal events in the root of the neck can involve the adjacent pleura and lung, and events in the adjacent pleura and lung can involve the root of the neck. One of the most important functions of the thorax is breathing. The thorax not only contains the lungs but also provides the machinery necessary—the diaphragm, thoracic wall, and ribs—for effectively moving air into and out of the lungs. Up and down movements of the diaphragm and changes in the lateral and anterior dimensions of the thoracic wall, caused by movements of the ribs, alter the volume of the thoracic cavity and are key elements in breathing. Protection of vital organs |
Anatomy_Gray_282 | Anatomy_Gray | Protection of vital organs The thorax houses and protects the heart, lungs, and great vessels. Because of the upward domed shape of the diaphragm, the thoracic wall also offers protection to some important abdominal viscera. Much of the liver lies under the right dome of the diaphragm, and the stomach and spleen lie under the left. The posterior aspects of the superior poles of the kidneys lie on the diaphragm and are anterior to rib XII, on the right, and to ribs XI and XII, on the left. The mediastinum acts as a conduit for structures that pass completely through the thorax from one body region to another and for structures that connect organs in the thorax to other body regions. The esophagus, vagus nerves, and thoracic duct pass through the mediastinum as they course between the abdomen and neck. The phrenic nerves, which originate in the neck, also pass through the mediastinum to penetrate and supply the diaphragm. | Anatomy_Gray. Protection of vital organs The thorax houses and protects the heart, lungs, and great vessels. Because of the upward domed shape of the diaphragm, the thoracic wall also offers protection to some important abdominal viscera. Much of the liver lies under the right dome of the diaphragm, and the stomach and spleen lie under the left. The posterior aspects of the superior poles of the kidneys lie on the diaphragm and are anterior to rib XII, on the right, and to ribs XI and XII, on the left. The mediastinum acts as a conduit for structures that pass completely through the thorax from one body region to another and for structures that connect organs in the thorax to other body regions. The esophagus, vagus nerves, and thoracic duct pass through the mediastinum as they course between the abdomen and neck. The phrenic nerves, which originate in the neck, also pass through the mediastinum to penetrate and supply the diaphragm. |
Anatomy_Gray_283 | Anatomy_Gray | The phrenic nerves, which originate in the neck, also pass through the mediastinum to penetrate and supply the diaphragm. Other structures such as the trachea, thoracic aorta, and superior vena cava course within the mediastinum en route to and from major visceral organs in the thorax. The thoracic wall consists of skeletal elements and muscles (Fig. 3.1): Posteriorly, it is made up of twelve thoracic vertebrae and their intervening intervertebral discs; Laterally, the wall is formed by ribs (twelve on each side) and three layers of flat muscles, which span the intercostal spaces between adjacent ribs, move the ribs, and provide support for the intercostal spaces; Anteriorly, the wall is made up of the sternum, which consists of the manubrium of sternum, body of sternum, and xiphoid process. | Anatomy_Gray. The phrenic nerves, which originate in the neck, also pass through the mediastinum to penetrate and supply the diaphragm. Other structures such as the trachea, thoracic aorta, and superior vena cava course within the mediastinum en route to and from major visceral organs in the thorax. The thoracic wall consists of skeletal elements and muscles (Fig. 3.1): Posteriorly, it is made up of twelve thoracic vertebrae and their intervening intervertebral discs; Laterally, the wall is formed by ribs (twelve on each side) and three layers of flat muscles, which span the intercostal spaces between adjacent ribs, move the ribs, and provide support for the intercostal spaces; Anteriorly, the wall is made up of the sternum, which consists of the manubrium of sternum, body of sternum, and xiphoid process. |
Anatomy_Gray_284 | Anatomy_Gray | Anteriorly, the wall is made up of the sternum, which consists of the manubrium of sternum, body of sternum, and xiphoid process. The manubrium of sternum, angled posteriorly on the body of sternum at the manubriosternal joint, forms the sternal angle, which is a major surface landmark used by clinicians in performing physical examinations of the thorax. The anterior (distal) end of each rib is composed of costal cartilage, which contributes to the mobility and elasticity of the wall. All ribs articulate with thoracic vertebrae posteriorly. Most ribs (from rib II to IX) have three articulations with the vertebral column. The head of each rib articulates with the body of its own vertebra and with the body of the vertebra above (Fig. 3.2). As these ribs curve posteriorly, each also articulates with the transverse process of its vertebra. Anteriorly, the costal cartilages of ribs I to VII articulate with the sternum. | Anatomy_Gray. Anteriorly, the wall is made up of the sternum, which consists of the manubrium of sternum, body of sternum, and xiphoid process. The manubrium of sternum, angled posteriorly on the body of sternum at the manubriosternal joint, forms the sternal angle, which is a major surface landmark used by clinicians in performing physical examinations of the thorax. The anterior (distal) end of each rib is composed of costal cartilage, which contributes to the mobility and elasticity of the wall. All ribs articulate with thoracic vertebrae posteriorly. Most ribs (from rib II to IX) have three articulations with the vertebral column. The head of each rib articulates with the body of its own vertebra and with the body of the vertebra above (Fig. 3.2). As these ribs curve posteriorly, each also articulates with the transverse process of its vertebra. Anteriorly, the costal cartilages of ribs I to VII articulate with the sternum. |
Anatomy_Gray_285 | Anatomy_Gray | Anteriorly, the costal cartilages of ribs I to VII articulate with the sternum. The costal cartilages of ribs VIII to X articulate with the inferior margins of the costal cartilages above them. Ribs XI and XII are called floating ribs because they do not articulate with other ribs, costal cartilages, or the sternum. Their costal cartilages are small, only covering their tips. The skeletal framework of the thoracic wall provides extensive attachment sites for muscles of the neck, abdomen, back, and upper limbs. A number of these muscles attach to ribs and function as accessory respiratory muscles; some of them also stabilize the position of the first and last ribs. Completely surrounded by skeletal elements, the superior thoracic aperture consists of the body of vertebra TI posteriorly, the medial margin of rib I on each side, and the manubrium anteriorly. | Anatomy_Gray. Anteriorly, the costal cartilages of ribs I to VII articulate with the sternum. The costal cartilages of ribs VIII to X articulate with the inferior margins of the costal cartilages above them. Ribs XI and XII are called floating ribs because they do not articulate with other ribs, costal cartilages, or the sternum. Their costal cartilages are small, only covering their tips. The skeletal framework of the thoracic wall provides extensive attachment sites for muscles of the neck, abdomen, back, and upper limbs. A number of these muscles attach to ribs and function as accessory respiratory muscles; some of them also stabilize the position of the first and last ribs. Completely surrounded by skeletal elements, the superior thoracic aperture consists of the body of vertebra TI posteriorly, the medial margin of rib I on each side, and the manubrium anteriorly. |
Anatomy_Gray_286 | Anatomy_Gray | Completely surrounded by skeletal elements, the superior thoracic aperture consists of the body of vertebra TI posteriorly, the medial margin of rib I on each side, and the manubrium anteriorly. The superior margin of the manubrium is in approximately the same horizontal plane as the intervertebral disc between vertebrae TII and TIII. The first ribs slope inferiorly from their posterior articulation with vertebra TI to their anterior attachment to the manubrium. Consequently, the plane of the superior thoracic aperture is at an oblique angle, facing somewhat anteriorly. At the superior thoracic aperture, the superior aspects of the pleural cavities, which surround the lungs, lie on either side of the entrance to the mediastinum (Fig. 3.3). | Anatomy_Gray. Completely surrounded by skeletal elements, the superior thoracic aperture consists of the body of vertebra TI posteriorly, the medial margin of rib I on each side, and the manubrium anteriorly. The superior margin of the manubrium is in approximately the same horizontal plane as the intervertebral disc between vertebrae TII and TIII. The first ribs slope inferiorly from their posterior articulation with vertebra TI to their anterior attachment to the manubrium. Consequently, the plane of the superior thoracic aperture is at an oblique angle, facing somewhat anteriorly. At the superior thoracic aperture, the superior aspects of the pleural cavities, which surround the lungs, lie on either side of the entrance to the mediastinum (Fig. 3.3). |
Anatomy_Gray_287 | Anatomy_Gray | At the superior thoracic aperture, the superior aspects of the pleural cavities, which surround the lungs, lie on either side of the entrance to the mediastinum (Fig. 3.3). Structures that pass between the upper limb and thorax pass over rib I and the superior part of the pleural cavity as they enter and leave the mediastinum. Structures that pass between the neck and head and the thorax pass more vertically through the superior thoracic aperture. The inferior thoracic aperture is large and expandable. Bone, cartilage, and ligaments form its margin (Fig. 3.4A). The inferior thoracic aperture is closed by the diaphragm, and structures passing between the abdomen and thorax pierce or pass posteriorly to the diaphragm. | Anatomy_Gray. At the superior thoracic aperture, the superior aspects of the pleural cavities, which surround the lungs, lie on either side of the entrance to the mediastinum (Fig. 3.3). Structures that pass between the upper limb and thorax pass over rib I and the superior part of the pleural cavity as they enter and leave the mediastinum. Structures that pass between the neck and head and the thorax pass more vertically through the superior thoracic aperture. The inferior thoracic aperture is large and expandable. Bone, cartilage, and ligaments form its margin (Fig. 3.4A). The inferior thoracic aperture is closed by the diaphragm, and structures passing between the abdomen and thorax pierce or pass posteriorly to the diaphragm. |
Anatomy_Gray_288 | Anatomy_Gray | The inferior thoracic aperture is closed by the diaphragm, and structures passing between the abdomen and thorax pierce or pass posteriorly to the diaphragm. Skeletal elements of the inferior thoracic aperture are: the body of vertebra TXII posteriorly, rib XII and the distal end of rib XI posterolaterally, the distal cartilaginous ends of ribs VII to X, which unite to form the costal margin anterolaterally, and the xiphoid process anteriorly. The joint between the costal margin and sternum lies roughly in the same horizontal plane as the intervertebral disc between vertebrae TIX and TX. In other words, the posterior margin of the inferior thoracic aperture is inferior to the anterior margin. When viewed anteriorly, the inferior thoracic aperture is tilted superiorly. The musculotendinous diaphragm seals the inferior thoracic aperture (Fig. 3.4B). | Anatomy_Gray. The inferior thoracic aperture is closed by the diaphragm, and structures passing between the abdomen and thorax pierce or pass posteriorly to the diaphragm. Skeletal elements of the inferior thoracic aperture are: the body of vertebra TXII posteriorly, rib XII and the distal end of rib XI posterolaterally, the distal cartilaginous ends of ribs VII to X, which unite to form the costal margin anterolaterally, and the xiphoid process anteriorly. The joint between the costal margin and sternum lies roughly in the same horizontal plane as the intervertebral disc between vertebrae TIX and TX. In other words, the posterior margin of the inferior thoracic aperture is inferior to the anterior margin. When viewed anteriorly, the inferior thoracic aperture is tilted superiorly. The musculotendinous diaphragm seals the inferior thoracic aperture (Fig. 3.4B). |
Anatomy_Gray_289 | Anatomy_Gray | When viewed anteriorly, the inferior thoracic aperture is tilted superiorly. The musculotendinous diaphragm seals the inferior thoracic aperture (Fig. 3.4B). Generally, muscle fibers of the diaphragm arise radially, from the margins of the inferior thoracic aperture, and converge into a large central tendon. Because of the oblique angle of the inferior thoracic aperture, the posterior attachment of the diaphragm is inferior to the anterior attachment. The diaphragm is not flat; rather, it “balloons” superiorly, on both the right and left sides, to form domes. The right dome is higher than the left, reaching as far as rib V. As the diaphragm contracts, the height of the domes decreases and the volume of the thorax increases. The esophagus and inferior vena cava penetrate the diaphragm; the aorta passes posterior to the diaphragm. | Anatomy_Gray. When viewed anteriorly, the inferior thoracic aperture is tilted superiorly. The musculotendinous diaphragm seals the inferior thoracic aperture (Fig. 3.4B). Generally, muscle fibers of the diaphragm arise radially, from the margins of the inferior thoracic aperture, and converge into a large central tendon. Because of the oblique angle of the inferior thoracic aperture, the posterior attachment of the diaphragm is inferior to the anterior attachment. The diaphragm is not flat; rather, it “balloons” superiorly, on both the right and left sides, to form domes. The right dome is higher than the left, reaching as far as rib V. As the diaphragm contracts, the height of the domes decreases and the volume of the thorax increases. The esophagus and inferior vena cava penetrate the diaphragm; the aorta passes posterior to the diaphragm. |
Anatomy_Gray_290 | Anatomy_Gray | The esophagus and inferior vena cava penetrate the diaphragm; the aorta passes posterior to the diaphragm. The mediastinum is a thick midline partition that extends from the sternum anteriorly to the thoracic vertebrae posteriorly, and from the superior thoracic aperture to the inferior thoracic aperture. A horizontal plane passing through the sternal angle and the intervertebral disc between vertebrae TIV and TV separates the mediastinum into superior and inferior parts (Fig. 3.5). The inferior part is further subdivided by the pericardium, which encloses the pericardial cavity surrounding the heart. The pericardium and heart constitute the middle mediastinum. The anterior mediastinum lies between the sternum and the pericardium; the posterior mediastinum lies between the pericardium and thoracic vertebrae. The two pleural cavities are situated on either side of the mediastinum (Fig. 3.6). Each pleural cavity is completely lined by a mesothelial membrane called the pleura. | Anatomy_Gray. The esophagus and inferior vena cava penetrate the diaphragm; the aorta passes posterior to the diaphragm. The mediastinum is a thick midline partition that extends from the sternum anteriorly to the thoracic vertebrae posteriorly, and from the superior thoracic aperture to the inferior thoracic aperture. A horizontal plane passing through the sternal angle and the intervertebral disc between vertebrae TIV and TV separates the mediastinum into superior and inferior parts (Fig. 3.5). The inferior part is further subdivided by the pericardium, which encloses the pericardial cavity surrounding the heart. The pericardium and heart constitute the middle mediastinum. The anterior mediastinum lies between the sternum and the pericardium; the posterior mediastinum lies between the pericardium and thoracic vertebrae. The two pleural cavities are situated on either side of the mediastinum (Fig. 3.6). Each pleural cavity is completely lined by a mesothelial membrane called the pleura. |
Anatomy_Gray_291 | Anatomy_Gray | The two pleural cavities are situated on either side of the mediastinum (Fig. 3.6). Each pleural cavity is completely lined by a mesothelial membrane called the pleura. During development, the lungs grow out of the mediastinum, becoming surrounded by the pleural cavities. As a result, the outer surface of each organ is covered by pleura. Each lung remains attached to the mediastinum by a root formed by the airway, pulmonary blood vessels, lymphatic tissues, and nerves. The pleura lining the walls of the cavity is the parietal pleura, whereas that reflected from the mediastinum at the roots and onto the surfaces of the lungs is the visceral pleura. Only a potential space normally exists between the visceral pleura covering lung and the parietal pleura lining the wall of the thoracic cavity. | Anatomy_Gray. The two pleural cavities are situated on either side of the mediastinum (Fig. 3.6). Each pleural cavity is completely lined by a mesothelial membrane called the pleura. During development, the lungs grow out of the mediastinum, becoming surrounded by the pleural cavities. As a result, the outer surface of each organ is covered by pleura. Each lung remains attached to the mediastinum by a root formed by the airway, pulmonary blood vessels, lymphatic tissues, and nerves. The pleura lining the walls of the cavity is the parietal pleura, whereas that reflected from the mediastinum at the roots and onto the surfaces of the lungs is the visceral pleura. Only a potential space normally exists between the visceral pleura covering lung and the parietal pleura lining the wall of the thoracic cavity. |
Anatomy_Gray_292 | Anatomy_Gray | The lung does not completely fill the potential space of the pleural cavity, resulting in recesses, which do not contain lung and are important for accommodating changes in lung volume during breathing. The costodiaphragmatic recess, which is the largest and clinically most important recess, lies inferiorly between the thoracic wall and diaphragm. The superior thoracic aperture opens directly into the root of the neck (Fig. 3.7). The superior aspect of each pleural cavity extends approximately 2 to 3 cm above rib I and the costal cartilage into the neck. Between these pleural extensions, major visceral structures pass between the neck and superior mediastinum. In the midline, the trachea lies immediately anterior to the esophagus. Major blood vessels and nerves pass in and out of the thorax at the superior thoracic aperture anteriorly and laterally to these structures. | Anatomy_Gray. The lung does not completely fill the potential space of the pleural cavity, resulting in recesses, which do not contain lung and are important for accommodating changes in lung volume during breathing. The costodiaphragmatic recess, which is the largest and clinically most important recess, lies inferiorly between the thoracic wall and diaphragm. The superior thoracic aperture opens directly into the root of the neck (Fig. 3.7). The superior aspect of each pleural cavity extends approximately 2 to 3 cm above rib I and the costal cartilage into the neck. Between these pleural extensions, major visceral structures pass between the neck and superior mediastinum. In the midline, the trachea lies immediately anterior to the esophagus. Major blood vessels and nerves pass in and out of the thorax at the superior thoracic aperture anteriorly and laterally to these structures. |
Anatomy_Gray_293 | Anatomy_Gray | An axillary inlet, or gateway to the upper limb, lies on each side of the superior thoracic aperture. These two axillary inlets and the superior thoracic aperture communicate superiorly with the root of the neck (Fig. 3.7). Each axillary inlet is formed by: the superior margin of the scapula posteriorly, the clavicle anteriorly, and the lateral margin of rib I medially. The apex of each triangular inlet is directed laterally and is formed by the medial margin of the coracoid process, which extends anteriorly from the superior margin of the scapula. The base of the axillary inlet’s triangular opening is the lateral margin of rib I. Large blood vessels passing between the axillary inlet and superior thoracic aperture do so by passing over rib I. Proximal parts of the brachial plexus also pass between the neck and upper limb by passing through the axillary inlet. | Anatomy_Gray. An axillary inlet, or gateway to the upper limb, lies on each side of the superior thoracic aperture. These two axillary inlets and the superior thoracic aperture communicate superiorly with the root of the neck (Fig. 3.7). Each axillary inlet is formed by: the superior margin of the scapula posteriorly, the clavicle anteriorly, and the lateral margin of rib I medially. The apex of each triangular inlet is directed laterally and is formed by the medial margin of the coracoid process, which extends anteriorly from the superior margin of the scapula. The base of the axillary inlet’s triangular opening is the lateral margin of rib I. Large blood vessels passing between the axillary inlet and superior thoracic aperture do so by passing over rib I. Proximal parts of the brachial plexus also pass between the neck and upper limb by passing through the axillary inlet. |
Anatomy_Gray_294 | Anatomy_Gray | Proximal parts of the brachial plexus also pass between the neck and upper limb by passing through the axillary inlet. The diaphragm separates the thorax from the abdomen. Structures that pass between the thorax and abdomen either penetrate the diaphragm or pass posteriorly to it (Fig. 3.8): The inferior vena cava pierces the central tendon of the diaphragm to enter the right side of the mediastinum near vertebral level TVIII. The esophagus penetrates the muscular part of the diaphragm to leave the mediastinum and enter the abdomen just to the left of the midline at vertebral level TX. The aorta passes posteriorly to the diaphragm at the midline at vertebral level TXII. Numerous other structures that pass between the thorax and abdomen pass through or posterior to the diaphragm. The breasts, consisting of mammary glands, superficial fascia, and overlying skin, are in the pectoral region on each side of the anterior thoracic wall (Fig. 3.9). | Anatomy_Gray. Proximal parts of the brachial plexus also pass between the neck and upper limb by passing through the axillary inlet. The diaphragm separates the thorax from the abdomen. Structures that pass between the thorax and abdomen either penetrate the diaphragm or pass posteriorly to it (Fig. 3.8): The inferior vena cava pierces the central tendon of the diaphragm to enter the right side of the mediastinum near vertebral level TVIII. The esophagus penetrates the muscular part of the diaphragm to leave the mediastinum and enter the abdomen just to the left of the midline at vertebral level TX. The aorta passes posteriorly to the diaphragm at the midline at vertebral level TXII. Numerous other structures that pass between the thorax and abdomen pass through or posterior to the diaphragm. The breasts, consisting of mammary glands, superficial fascia, and overlying skin, are in the pectoral region on each side of the anterior thoracic wall (Fig. 3.9). |
Anatomy_Gray_295 | Anatomy_Gray | The breasts, consisting of mammary glands, superficial fascia, and overlying skin, are in the pectoral region on each side of the anterior thoracic wall (Fig. 3.9). Vessels, lymphatics, and nerves associated with the breast are as follows: Branches from the internal thoracic arteries and veins perforate the anterior chest wall on each side of the sternum to supply anterior aspects of the thoracic wall. Those branches associated mainly with the second to fourth intercostal spaces also supply the anteromedial parts of each breast. Lymphatic vessels from the medial part of the breast accompany the perforating arteries and drain into the parasternal nodes on the deep surface of the thoracic wall. Vessels and lymphatics associated with lateral parts of the breast emerge from or drain into the axillary region of the upper limb. Lateral and anterior branches of the fourth to sixth intercostal nerves carry general sensation from the skin of the breast. | Anatomy_Gray. The breasts, consisting of mammary glands, superficial fascia, and overlying skin, are in the pectoral region on each side of the anterior thoracic wall (Fig. 3.9). Vessels, lymphatics, and nerves associated with the breast are as follows: Branches from the internal thoracic arteries and veins perforate the anterior chest wall on each side of the sternum to supply anterior aspects of the thoracic wall. Those branches associated mainly with the second to fourth intercostal spaces also supply the anteromedial parts of each breast. Lymphatic vessels from the medial part of the breast accompany the perforating arteries and drain into the parasternal nodes on the deep surface of the thoracic wall. Vessels and lymphatics associated with lateral parts of the breast emerge from or drain into the axillary region of the upper limb. Lateral and anterior branches of the fourth to sixth intercostal nerves carry general sensation from the skin of the breast. |
Anatomy_Gray_296 | Anatomy_Gray | Lateral and anterior branches of the fourth to sixth intercostal nerves carry general sensation from the skin of the breast. When working with patients, physicians use vertebral levels to determine the position of important anatomical structures within body regions. | Anatomy_Gray. Lateral and anterior branches of the fourth to sixth intercostal nerves carry general sensation from the skin of the breast. When working with patients, physicians use vertebral levels to determine the position of important anatomical structures within body regions. |
Anatomy_Gray_297 | Anatomy_Gray | The horizontal plane passing through the disc that separates thoracic vertebrae TIV and TV is one of the most significant planes in the body (Fig. 3.10) because it: passes through the sternal angle anteriorly, marking the position of the anterior articulation of the costal cartilage of rib II with the sternum. The sternal angle is used to find the position of rib II as a reference for counting ribs (because of the overlying clavicle, rib I is not palpable); separates the superior mediastinum from the inferior mediastinum and marks the position of the superior limit of the pericardium; marks where the arch of the aorta begins and ends; passes through the site where the superior vena cava penetrates the pericardium to enter the heart; is the level at which the trachea bifurcates into right and left main bronchi; and marks the superior limit of the pulmonary trunk. Venous shunts from left to right | Anatomy_Gray. The horizontal plane passing through the disc that separates thoracic vertebrae TIV and TV is one of the most significant planes in the body (Fig. 3.10) because it: passes through the sternal angle anteriorly, marking the position of the anterior articulation of the costal cartilage of rib II with the sternum. The sternal angle is used to find the position of rib II as a reference for counting ribs (because of the overlying clavicle, rib I is not palpable); separates the superior mediastinum from the inferior mediastinum and marks the position of the superior limit of the pericardium; marks where the arch of the aorta begins and ends; passes through the site where the superior vena cava penetrates the pericardium to enter the heart; is the level at which the trachea bifurcates into right and left main bronchi; and marks the superior limit of the pulmonary trunk. Venous shunts from left to right |
Anatomy_Gray_298 | Anatomy_Gray | Venous shunts from left to right The right atrium is the chamber of the heart that receives deoxygenated blood returning from the body. It lies on the right side of the midline, and the two major veins, the superior and inferior venae cavae, that drain into it are also located on the right side of the body. This means that, to get to the right side of the body, all blood coming from the left side has to cross the midline. This left-to-right shunting is carried out by a number of important and, in some cases, very large veins, several of which are in the thorax (Fig. 3.11). In adults, the left brachiocephalic vein crosses the midline immediately posterior to the manubrium and delivers blood from the left side of the head and neck, the left upper limb, and part of the left thoracic wall into the superior vena cava. | Anatomy_Gray. Venous shunts from left to right The right atrium is the chamber of the heart that receives deoxygenated blood returning from the body. It lies on the right side of the midline, and the two major veins, the superior and inferior venae cavae, that drain into it are also located on the right side of the body. This means that, to get to the right side of the body, all blood coming from the left side has to cross the midline. This left-to-right shunting is carried out by a number of important and, in some cases, very large veins, several of which are in the thorax (Fig. 3.11). In adults, the left brachiocephalic vein crosses the midline immediately posterior to the manubrium and delivers blood from the left side of the head and neck, the left upper limb, and part of the left thoracic wall into the superior vena cava. |
Anatomy_Gray_299 | Anatomy_Gray | The hemiazygos and accessory hemiazygos veins drain posterior and lateral parts of the left thoracic wall, pass immediately anterior to the bodies of thoracic vertebrae, and flow into the azygos vein on the right side, which ultimately connects with the superior vena cava. The arrangement of vessels and nerves that supply the thoracic wall reflects the segmental organization of the wall. Arteries to the wall arise from two sources: the thoracic aorta, which is in the posterior mediastinum, and a pair of vessels, the internal thoracic arteries, which run along the deep aspect of the anterior thoracic wall on either side of the sternum. | Anatomy_Gray. The hemiazygos and accessory hemiazygos veins drain posterior and lateral parts of the left thoracic wall, pass immediately anterior to the bodies of thoracic vertebrae, and flow into the azygos vein on the right side, which ultimately connects with the superior vena cava. The arrangement of vessels and nerves that supply the thoracic wall reflects the segmental organization of the wall. Arteries to the wall arise from two sources: the thoracic aorta, which is in the posterior mediastinum, and a pair of vessels, the internal thoracic arteries, which run along the deep aspect of the anterior thoracic wall on either side of the sternum. |