Thoracic segmental flexion during cervical forward bending.

The purpose of this study was to assess the amount of thoracic segmental flexion associated with cervical forward bending. Twenty-four healthy men and women between the ages of 21-29, with no past or present cervical or thoracic dysfunction, participated. Spinal segmental mobility in the thoracic region was measured in the neutral sitting position and sitting with the cervical spine in the forward bent position. Mobility was measured by the Faro Metrecom Skeletal Analysis System. The Faro Metrecom is an external measuring device that records each individual spinal segment's position within the body. Descriptive statistics were used to describe the position of the thoracic segments when the cervical region was in the neutral and in the forward bent positions. Additionally, intrarater reliability, .83 and .76, and interrater, .72, were analyzed for the thoracic segments in the neutral position. The results show that with cervical flexion there was thoracic segmental flexion. Segments T1-4 demonstrated forward bending ranging from 2.88-4.42°. The greatest amount of flexion occurred at T2, 4.42 degrees, and T3, 4.19 degrees. Below T4 no pattern was noted. The results indicate that upper-thoracic segmental flexion occurs during cervical forward bending.During evaluation and treatment of patients with cervical dysfunction physical therapists routinely evaluate spinal segmental mobility. It is clear to clinicians that cervical segmental mobility is important to cervical range of motion. What it not clear is the role of thoracic segmental mobility in cervical range of motion. Physical therapists frequently evaluate and treat the thoracic region when patients have cervical dysfunction. Therefore, the purpose of this study was to assess the amount of thoracic segmental flexion associated with cervical forward bending.Since the early 1970s when the concept of joint mobilization was brought to American physical therapists, interest in spinal segmental motion has increased. Though interest in this area exists, there is a scarcity ofresearch documenting normal and abnormal spinal segmental mobility. Additionally, most of the studies on spinal segmental mobility have been conducted on cadavers or through radiographic methods.Lysell studied intersegmental movements of the cervical spine using autopsy specimens. Steel balls were placed in fixed points on each vertebrae and then a three-dimensional radiographic examination was used to measure movements of these points during cervical range of motion.1 Ball and Meijers studied cervical mobility using fresh cadaveric cervical spinal specimens. In this study steel pins were inserted into the cervical bodies and serial x-rays were taken.2 Panjabi, Dvorak, and Duranceau studied upper-cervical spine mobility using fresh cadaveric whole cervical spine specimens and steel balls. Their specimens were set into a quick-setting epoxy material to help align the centers of C2 and C7, thereby providing fixation.3 Yamamoto et al. studied three-dimensional movements of the lumbar spine and lumbosacral joint. They used fresh cadaveric whole lumbar spine specimens analyzing from L1 to the sacrum.4 Robert studied intervertebral motion of the whole spine. This was performed with cadavers as the segmental excursions were determined from a point at the inferior surface of the vertebrae to the tip of the spinous process.5Three separate noncadaveric studies were conducted by Penning,6 Felding7 and Moll and Wright.8 Penning studied normal movements of the cervical spine by superimposing two x-ray films representing the cervical spine in the end positions (i.e., flexion and extension). Fielding studied normal and abnormal motion of the cervical spine from C2 and C7 using cineroentgenography; roentgenograms were taken while the subjects were moving. Moll and Wright studied normal range of spinal mobility using live subjects with markers on the skin. When the subjects moved the separation of the skin markers was recorded.The above studies used procedures that are not convenient for use during clinical sessions. Additionally, the above studies did not evaluate thoracic mobility in relation to cervical motion.In the textbook, Common Vertebral joint Problems,9 Grieve presents a complete discussion of vertebral motion. This section is highly referenced as it pertains to segmental spinal mobility.9 White and Panjabi are the most frequently cited source on spinal segmental mobility.10,11 They reported flexion/extension degrees of motion for the thoracic segments. The ranges of the motion and the "representative angle" (most likely the mean angle) in degrees for each thoracic segment are T1-T5 2-5 (4); T6 2-7 (5); T7-T9 3-8 (6); T10 4-14 (9); and T11-T12 6-20 (12). However, they did not state how their estimated range and "representative angle" in degrees of segmental spinal mobility were measured.10,11 Valencia in the book Physical Therapy of the Cervical and Thoracic Spine states similar motion for the thoracic segments.12The upper-thoracic spine, T1-T6, has been related to the cervical region anatomically. The upper-thoracic facet joints are orientated like the cervical facet joints and have a similar pattern of movement.11,13 Additionally, the caudal attachment of many cervical muscles is in the thoracic region.13.