J98.6 - Disorders of diaphragm, Diaphragmatitis, Paralysis of diaphragm, Relaxation of diaphragm, Br BREATHING Illustration of human body changes by breathing Breathing is the process that takes oxygen in and carbon dioxide in and then out of the lungs. Aerobic organisms require oxygen to release energy via respiration, in the form of the metabolism of energy-rich molecules such as glucose. The medical term for normal relaxed breathing is eupnea. Breathing is only part of the processes that deliver oxygen to where it is needed in the body and remove carbon dioxide. The process of gas exchange occurs in the pulmonairy alveoli by passive diffusion of gases between the alveolar gas and the blood passing by in the lung capillaries. Once these dissolved gases are in the blood, the heart powers their flow around the body (via the circulatory system). In addition to removing carbon dioxide, breathing results in loss of water from the body. Exhaled air has a relative humidity of 100% because of water diffusing across the moist surface of breathing passages and alveoli.

Mechanics In mammals, breathing in, or inhaling, is usually an active movement, with the contraction of the diaphragm muscle. This is known as negative pressure breathing. Normally, the diaphragm's relaxed position recoils (decreasing the thoracic volume) whereas in the contracted position it is pulled downwards (increasing the thoracic volume). This process works in conjunction with the intercostal muscles connected to the rib cage. Contraction of these muscles lifts the rib cage, thus aiding in increasing the thoracic volume. Relaxation of the diaphragm compresses the lungs, effectively decreasing their volume while increasing the pressure inside them. The intercostal muscles simultaneously relax, further decreasing the volume of the lungs. With a pathway to the mouth or nose clear, this increased pressure forces air out of the lungs. Conversely, contraction of the diaphragm increases the volume of the (partially empty) lungs, decreasing the pressure inside, which creates a partial vacuum. Environmental air then follows its pressure gradient down to fill the lungs. In amphibians, the process used is positive pressure breathing.

Muscles lower the floor of the oral cavity, enlarging it and drawing in air through the nostrils (which uses the same mechanics - pressure, volume, and diffusion - as a mammalian lung). With the nostrils and mouth closed, the floor of the oral cavity is forced up, which forces air down the trachea into the lungs. At rest, breathing out, or exhaling, is a combination of passive and active processes powered by the elastic recoil of the alveoli, similar to a deflating balloon, and the contraction of the muscular body wall. The following organs are used in respiration: the mouth; the nose and nostrils; the pharynx; the larynx; the trachea; the bronchi and bronchioles; the lungs; the diaphragm; and the terminal branches of the respiratory tree, such as the alveoli. Control of breathing Breathing is one of the few bodily functions which, within limits, can be controlled both consciously and unconsciously. Conscious control Conscious control of breathing is common in many forms of meditation, specifically forms of yoga for example pranayama unlike anapana which is only awareness of breath.

In swimming, cardio fitness, speech or vocal training, one learns to discipline one's breathing, initially consciously but later sub-consciously, for purposes other than life support. Human speech is also dependent on conscious breath control. Also breathing control is used in Buteyko method. Unconscious control Unconsciously, breathing is controlled by specialized centers in the brainstem, which automatically regulate the rate and depth of breathing depending on the body’s needs at any time. When carbon dioxide levels increase in the blood, it reacts with the water in blood, producing carbonic acid. Lactic acid produced by anaerobic exercise also lowers pH. The drop in the blood's pH stimulates chemoreceptors in the carotid and aortic bodies in the blood system to send nerve impulses to the respiration centre in the medulla oblongata and pons in the brain. These, in turn send nerve impulses through the phrenic and thoracic nerves to the diaphragm and the intercostal muscles, increasing the rate of breathing. Even a slight difference in the blood's normal pH, 7.4, could cause death, so this is an important process. This automatic control of respiration can be impaired in premature babies, or by drugs or disease.

Examples For instance, while exercising, the level of carbon dioxide in the blood increases due to increased cellular respiration by the muscles, which activates carotid and aortic bodies and the respiration center, which ultimately cause a higher rate of respiration. During rest, the level of carbon dioxide is lower, so breathing rate is lower. This ensures an appropriate amount of oxygen is delivered to the muscles and other organs. It is important to reiterate that it is the buildup of carbon dioxide making the blood acidic that elicits the desperation for a breath much more than lack of oxygen. Interaction It is not possible for a healthy person to voluntarily stop breathing indefinitely. If we do not inhale, the level of carbon dioxide builds up in our blood, and we experience overwhelming air hunger. This irrepressible reflex is not surprising given that without breathing, the body's internal oxygen levels drop dangerously low within minutes, leading to permanent brain damage followed eventually by death. However, there have been instances where people have survived for as long as two hours without air; this is only possible when submerged in cold water, as this triggers the mammalian diving reflex as well as putting the subject into a state of suspended animation. If a healthy person were to voluntarily stop breathing (i.e.

hold his or her breath) for a long enough amount of time, he or she would lose consciousness, and the body would resume breathing on its own. Because of this one cannot commit suicide with this method, unless one's breathing was also restricted by something else (e.g. water, see drowning) Hyperventilating causes a drop in CO 2 below normal levels, lowering blood and oxygen supply to vital organs due to CO2-induced vasoconstriction and suppressed Bohr effect. Voluntary hyperventilation can cause tissue oxygen levels to go to dangerously low levels leading to, for example, fainting due to brain hypoxia. Breathing in the sick Medical respiratory data (see the table below) suggest that sick people breathe about 2-3 times more air at rest than the medical norm. (Source: There are many more medical studies that found 100% prevalence of chronic hyperventilation in patients with various chronic diseases. Breathing in gas Components Oxygen is the essential component of all breathing gases.

The air we inhale is roughly 78% by volume nitrogen, 21% oxygen, 0.96% argon and 0.04% carbon dioxide, helium, water, and other gases. In addition to air, underwater divers often breathe oxygen-rich or helium-rich gas mixes. Oxygen and analgesic gases are sometimes given to patients under medical care. The atmosphere in space suits is pure oxygen. Also our reliance on this relatively small amount of oxygen can cause over activity or euphoria in pure or oxygen rich environments. The permanent gases in gas we exhale are roughly 4% to 5% more carbon dioxide and 4% to 5% less oxygen than was inhaled. Additionally vapors and trace gases are present: 5% water vapor, several parts per million (ppm) of hydrogen and carbon monoxide, 1 part per million (ppm) of ammonia and less than 1 ppm of acetone, methanol, ethanol (unless ethanol has been ingested, in which case much higher concentrations would occur in the breath, cf. Breathalyzer) and other volatile organic compounds.

The exact amount of exhaled oxygen and carbon dioxide varies according to the fitness, energy expenditure and diet of that particular person. Air pressure Atmospheric air at altitude is at a lower pressure than at sea level due to the lesser weight of the air above. This lower pressure can lead to altitude sickness, or hypoxia. Gases breathed underwater are at higher pressure than at sea level due to the added weight of water. This can lead to nitrogen narcosis, oxygen toxicity, or decompression sickness. Cultural significance In Tai Chi Chuan, aerobic training is combined with breathing to exercise the diaphragm muscles, and to train effective posture, which both make better use of the body's energy. In music, breath is used to play wind instruments and many aerophones. Laughter, physically, is simply repeated sharp breaths. Hiccups and yawns are other breath-related phenomena. Ancients commonly linked the breath to a life force. The Hebrew Bible refers to God breathing the breath of life into clay to make Adam a living soul (nephesh). It also refers to the breath as returning to God when a mortal dies. The terms spirit, qi, and psyche are related to the concept of breath.

See also ⇒ Full text MUSCLES OF RESPIRATION The various muscles of respiration aid in both inspiration and expiration, which require changes in the pressure within the thoracic cavity. The respiratory muscles work to achieve this by changing the dimensions of the thoracic cavity. The principal muscles are the diaphragm, the external intercostal and the intercondral part of the internal intercostal muscles. Both the external intercostal muscles and the intercondral elevate the ribs, thus increasing the width of the thoracic cavity, while the diaphragm contracts to increase the vertical dimensions of the thoracic cavity, and also aids in the elevation of the lower ribs. Accessory muscles are typically only used when the body needs to process energy quickly (e.g. during heavy exercise, during the stress response, or during an asthma attack). The accessory muscles of inspiration can also become engaged in everyday breathing when a breathing pattern disorder exists. The diaphragm The diaphragm is crucial for breathing and respiration. During inhalation, the diaphragm contracts, thus enlarging the thoracic cavity (the external intercostal muscles also participate in this enlargement).

This reduces intra-thoracic pressure: in other words, enlarging the cavity creates suction that draws air into the lungs. When the diaphragm relaxes, air is exhaled by elastic recoil of the lung and the tissues lining the thoracic cavity in conjunction with the abdominal muscles which act as an antagonist paired with the diaphragm's contraction. It is not responsible for all the breathing related to voice, a common misconception espoused by many teachers but few great singers. One has more control over the abdominals and intercostals than the actual diaphragm, which has relatively few proprioceptive nerve endings. By training proper posture and balance in the rest of the body, the diaphragm naturally strengthens and works in concert with surrounding structures rather than in isolation. The diaphragm is also involved in non-respiratory functions, helping to expel vomit, feces, and urine from the body by increasing intra-abdominal pressure, and preventing acid reflux by exerting pressure on the esophagus as it passes through the esophageal hiatus. The intercostal muscles Along with the diaphragm, the intercostal muscles are one of the most important groups of respiratory muscles.

These muscles are attached between each rib and are important in manipulating the width of the thoracic cage. There are three layers of intercostal muscles: ⇒ The external intercostal have fibres that go forward and downward (obliquely downward and forward from rib to rib ). These fibres are called the antero-inferior, and are sometimes referred to as the front pocket muscle since the fibres mimic the direction a hand would enter a front pocket. The external intercostals assist in deep inspiration by increasing the anterioposterior diameter of the chest. ⇒ The internal intercostal also have fibres, which go backward and downward (obliquely downward and posteriorly from rib to rib ). These are called the postero-superior, or the back pocket muscles . The internal intercostals assist in expiration by pulling the ribcage down. ⇒ The last layer is the innermost intercostals and consists of three separate parts; the subcostal (posteriorly), the innermost intercostal (laterally, which often causes confusion with the innermost intercostal referring to all twenty groups) and the transversus thoracis (anteriorly).

The antero-inferior fibres have the effect of lifting up the ribs during contraction. Anteriorly, the external intercostal muscles do not directly attach to the sternum, but are replaced by the anterior intercostal membrane. The innermost intercostal muscles are also back pocket muscles. The internal and innermost intercostals have the opposite effect of the external intercostals and aid in forced expiration. The internal intercostal is replaced by the posterior intercostal membrane posteriorly. Accessory muscles of inspiration There is some controversy as to which muscles may be considered accessory muscles of inspiration (Kendalll, McCreary, Provance, Rodgers, Romani, 2005). The sternocleidomastoid (elevated sternum) and the scalene muscles (anterior, middle and posterior scalene) are typically considered accessory muscles of breathing . If a breathing pattern disorder exists, the accessory muscles of inspiration may become overused. Muscles of expiration During quiet breathing, there is little or no muscle contraction/relaxation involved in expiration. This process is simply driven by the elastic recoil of the lungs in healthy individuals.

In certain conditions the elasticity of the lung can be lost, such as in emphysema. Forced (active) expiration occurs in such individuals as well as occurring during exercise. The abdominal muscles and the internal and innermost intercostal muscles help expel air. References Kendall, F., McCreary, E., Provance, P., Rodgers, M., Romai, W. (2005). Muscles testing and function with posture and pain (5th ed.). PA, USA: Lippincott Williams & Wilkins. respiration is under voluntary control also DIAPHRAGMATIC BREATHING Diaphragmatic breathing, abdominal breathing, belly breathing, deep breathing or costal breathing is the act of breathing deep into one's lungs by flexing one's diaphragm rather than breathing shallowly by flexing one's rib cage. This deep breathing is marked by expansion of the stomach (abdomen) rather than the chest when breathing. It is generally considered a healthier and fuller way to ingest oxygen, and is often used as a therapy for hyperventilation, anxiety disorders and stuttering. Some yoga and meditation traditions draw a clear distinction between diaphragmatic breathing and abdominal breathing or belly breathing.

The more specific technique of diaphragmatic breathing is said to be more beneficial. Although the diaphragm is the primary breathing muscle, it is believed that many people have little sensory awareness of it, almost no idea how to engage it more fully, and even how it works. Some breath therapists and breathing teachers believe that because of the increasing stress of modern life and the resulting over-stimulation of the sympathetic nervous system, as well as of the idealised hard, flat belly, many people carry excessive tension in the belly, chest, and back, which makes it difficult for the diaphragm to move freely through its full range of motion. Overview Performing diaphragmatic breathing can be therapeutic, and with enough practice, can become a standard way of breathing. To breathe diaphragmatically, or with the diaphragm, one must draw air into the lungs in a way which will expand the stomach and not the chest. It is best to perform these breaths as long, slow intakes of air - allowing the body to absorb all of the inhaled oxygen while simultaneously relaxing the breather.

To do this comfortably, it is often best to loosen tight-fitting pants/belts/skirts (nude also works well), as these can interfere with the body's ability to intake air. While at first one may not feel comfortable expanding the stomach during breathing, diaphragmatic breathing actually fills up the majority of the lungs with oxygen - much more than chest-breathing or shallow breathing. Many yoga and pranayama teachers believe that the most complete and fullest way of breathing is the three-part breath, also called in yoga The Complete Breath, which includes diaphragmatic breathing as the first step, followed by thorax expansion and then chest expansion. This method of breathing is considered in Tantric yoga to facilitate the greatest flow of life force through the body. There are several variations of the three-part breath ; however, many breath therapists and breathing teachers maintain that this approach can create breathing imbalances and other problems. Caveat One thing to note is that for some, the diaphragm is dysfunctional, in which case one should focus on slow inhalation and exhalation (through the nose and pursed lips). During stress and anger, we tend to inhale and hold our breath.

The most significant, therapeutic aspect of this breathing is the exhalation - which is at least twice the length of the inhalation. The exhalation alerts the body that it can relax and resume essential body functions and not remain in a state of fight or flight . Stuttering/Stammering A form of diaphragmatic breathing (often referred to as costal breathing ) is taught by several therapy programmes including the Starfish Project and the McGuire Programme as a method of treating stuttering. Many people who stutter have reported success in using diaphragmatic breathing to help them gain more control over their speech. See also ⇒ Breathing Exercises For Stress relief MUSCLES OF RESPIRATION The various muscles of respiration aid in both inspiration and expiration, which require changes in the pressure within the thoracic cavity. The respiratory muscles work to achieve this by changing the dimensions of the thoracic cavity. The principal muscles are the diaphragm, the external intercostal and the intercondral part of the internal intercostal muscles.

Both the external intercostal muscles and the intercondral elevate the ribs, thus increasing the width of the thoracic cavity, while the diaphragm contracts to increase the vertical dimensions of the thoracic cavity, and also aids in the elevation of the lower ribs. Accessory muscles are typically only used when the body needs to process energy quickly (e.g. during heavy exercise, during the stress response, or during an asthma attack). The accessory muscles of inspiration can also become engaged in everyday breathing when a breathing pattern disorder exists. The diaphragm The diaphragm is crucial for breathing and respiration. During inhalation, the diaphragm contracts, thus enlarging the thoracic cavity (the external intercostal muscles also participate in this enlargement). This reduces intra-thoracic pressure: in other words, enlarging the cavity creates suction that draws air into the lungs. When the diaphragm relaxes, air is exhaled by elastic recoil of the lung and the tissues lining the thoracic cavity in conjunction with the abdominal muscles which act as an antagonist paired with the diaphragm's contraction. It is not responsible for all the breathing related to voice, a common misconception espoused by many teachers but few great singers.

One has more control over the abdominals and intercostals than the actual diaphragm, which has relatively few proprioceptive nerve endings. By training proper posture and balance in the rest of the body, the diaphragm naturally strengthens and works in concert with surrounding structures rather than in isolation. The diaphragm is also involved in non-respiratory functions, helping to expel vomit, feces, and urine from the body by increasing intra-abdominal pressure, and preventing acid reflux by exerting pressure on the esophagus as it passes through the esophageal hiatus. The intercostal muscles Along with the diaphragm, the intercostal muscles are one of the most important groups of respiratory muscles. These muscles are attached between each rib and are important in manipulating the width of the thoracic cage. There are three layers of intercostal muscles: ⇒ The external intercostal have fibres that go forward and downward (obliquely downward and forward from rib to rib ). These fibres are called the antero-inferior, and are sometimes referred to as the front pocket muscle since the fibres mimic the direction a hand would enter a front pocket.

The external intercostals assist in deep inspiration by increasing the anterioposterior diameter of the chest. ⇒ The internal intercostal also have fibres, which go backward and downward (obliquely downward and posteriorly from rib to rib ). These are called the postero-superior, or the back pocket muscles . The internal intercostals assist in expiration by pulling the ribcage down. ⇒ The last layer is the innermost intercostals and consists of three separate parts; the subcostal (posteriorly), the innermost intercostal (laterally, which often causes confusion with the innermost intercostal referring to all twenty groups) and the transversus thoracis (anteriorly). The antero-inferior fibres have the effect of lifting up the ribs during contraction. Anteriorly, the external intercostal muscles do not directly attach to the sternum, but are replaced by the anterior intercostal membrane. The innermost intercostal muscles are also back pocket muscles. The internal and innermost intercostals have the opposite effect of the external intercostals and aid in forced expiration. The internal intercostal is replaced by the posterior intercostal membrane posteriorly.

Accessory muscles of inspiration There is some controversy as to which muscles may be considered accessory muscles of inspiration (Kendalll, McCreary, Provance, Rodgers, Romani, 2005). The sternocleidomastoid (elevated sternum) and the scalene muscles (anterior, middle and posterior scalene) are typically considered accessory muscles of breathing . If a breathing pattern disorder exists, the accessory muscles of inspiration may become overused. Muscles of expiration During quiet breathing, there is little or no muscle contraction/relaxation involved in expiration. This process is simply driven by the elastic recoil of the lungs in healthy individuals. In certain conditions the elasticity of the lung can be lost, such as in emphysema. Forced (active) expiration occurs in such individuals as well as occurring during exercise. The abdominal muscles and the internal and innermost intercostal muscles help expel air. References Kendall, F., McCreary, E., Provance, P., Rodgers, M., Romai, W. (2005). Muscles testing and function with posture and pain (5th ed.). PA, USA: Lippincott Williams & Wilkins.

respiration is under voluntary control also CONGENITAL DIAPHRAGMATIC HERNIA Congenital diaphragmatic hernia (CDH) is a congenital malformation (birth defect) of the diaphragm. The most common type of CDH is a Bochdalek hernia; other types include Morgagni's hernia, diaphragm eventration and central tendon defects of the diaphragm. Malformation of the diaphragm allows the abdominal organs to push into the chest thereby impeding proper lung formation. CDH is a life-threatening pathology in infants, and a major cause of death due to two complications: pulmonary hypoplasia and pulmonary hypertension. Newborns with CDH often have severe respiratory distress which can be life-threatening unless treated appropriately. Types of congenital diaphragmatic hernia Bochdalek hernia The Bochdalek hernia, also known as a postero-lateral diaphragmatic hernia, is the most common manifestation of CDH, accounting for more than 95% of cases. Morgagni's hernia This rare anterior defect of the diaphragm is variably referred to as Morgagni’s, retrosternal, or parasternal hernia.

Accounting for approximately 2% of all CDH cases, it is characterised by herniation through the foramina of Morgagni which are located immediately adjacent to the xiphoid process of the sternum. Pathophysiology It involves three major defects. ⇒ A failure of the diaphragm to completely close during development. ⇒ Herniation of the abdominal contents into the chest ⇒ Pulmonary hypoplasia Morbidity and mortality Congenital Diaphragmatic Hernia has a mortality rate of 40-62%, outcomes being more favorable in the absence of other congenital abnormalities. Individual rates vary greatly dependent upon multiple factors; size of hernia, organs involved, additional birth defects or genetic problems, amount of lung growth, age and size at birth, type of treatments, timing of treatments, complications such as infections and lack of lung function. Presentation and diagnosis This condition can often be diagnosed before birth and fetal intervention can sometimes help, depending on the severity of the condition. - report of new operation, pioneered at London's King's College Hospital which reduced death rates in the most at risk by 50% Infants born with diaphragmatic hernia experience respiratory failure due to both pulmonary hypertension and pulmonary hypoplasia.

The first condition is a restriction of blood flow through the lungs thought to be caused by defects in the lung. Pulmonary hypoplasia or decreased lung volume is directly related to the abdominal organs presence in the chest cavity which causes the lungs to be severely undersized, especially on the side of the hernia. Survival rates for infants with this condition vary, but have generally been increasing through advances in neonatal medicine. Work has been done to correlate survival rates to ultrasound measurements of the lung volume as compared to the baby's head circumference. This figure known as the lung to head ratio (LHR). Treatment First step in management is orogastric tube placement and securing the airway (intubation). The baby will usually be immediately placed on a ventilator. ECMO has been used as part of the treatment strategy at some hospitals. Plication basically involves a folding of the eventrated diaphragm which is then sutured in order to “take up the slack” of the excess diaphragm tissue.

See also References External links ⇒ CDH Rainbows - Informational website for those affected by the birth defect known as congenital diaphragmatic hernia HERNIA A hernia is the protrusion of an organ or the fascia of an organ through the wall of the cavity that normally contains it. A hiatal hernia occurs when the stomach protrudes into the mediastinum through the esophageal opening in the diaphragm. By far the most common herniae develop in the abdomen, when a weakness in the abdominal wall evolves into a localized hole, or defect, through which adipose tissue, or abdominal organs covered with peritoneum, may protrude. Another common hernia involves the spinal discs and causes sciatica. Herniae may or may not present either with pain at the site, a visible or palpable lump, or in some cases by more vague symptoms resulting from pressure on an organ which has become stuck in the hernia, sometimes leading to organ dysfunction. Fatty tissue usually enters a hernia first, but it may be followed by or accompanied by an organ. Most of the time, herniae develop when pressure in the compartment of the residing organ is increased, and the boundary is weak or weakened.

⇒ Weakening of containing membranes or muscles is usually congenital (which explains part of the tendency of herniae to run in families), and increases with age (for example, degeneration of the annulus fibrosus of the intervertebral disc), but it may be on the basis of other illnesses, such as Ehlers-Danlos syndrome or Marfan syndrome, stretching of muscles during pregnancy, losing weight in obese people, etc., or because of scars from previous surgery. ⇒ Many conditions chronically increase intra-abdominal pressure, (pregnancy, ascites, COPD, dyschezia, benign prostatic hypertrophy) and hence abdominal hernias are very frequent. Increased intracranial pressure can cause parts of the brain to herniate through narrowed portions of the cranial cavity or through the foramen magnum. Increased pressure on the intervertebral discs, as produced by heavy lifting or lifting with improper technique, increases the risk of herniation. Classification A sportman's hernia is a syndrome characterized by chronic groin' pain in athletes and a dilated superficial ring of the inguinal canal, although a true hernia is not present. Inguinal view from the left).

repair of inguinal hernia By far the most common hernias (up to 75% of all abdominal hernias) are the so-called inguinal hernias. Much insight is needed in the anatomy of the inguinal canal. Inguinal hernias are further divided into the more common indirect inguinal hernia (2/3, depicted here), in which the inguinal canal is entered via a congenital weakness at its entrance (the internal inguinal ring), and the direct inguinal hernia type (1/3), where the hernia contents push through a weak spot in the back wall of the inguinal canal. Inguinal hernias are the most common type of hernia in both men and women. Femoral hernias occur more often in women than men, but women still get more inguinal hernias than femoral hernias. Femoral Femoral hernias occur just below the inguinal ligament, when abdominal contents pass into the weak area at the posterior wall of the femoral canal.

They can be hard to distinguish from the inguinal type (especially when ascending cephalad): however, they generally appear more rounded, and, in contrast to inguinal hernias, there is a strong female preponderance in femoral hernias. The incidence of strangulation in femoral hernias is high. Repair techniques are similar for femoral and inguinal hernia. Umbilical Umbilical hernias are especially common in infants of African descent, and occur more in boys. They involve protrusion of intraabdominal contents through a weakness at the site of passage of the umbilical cord through the abdominal wall. These hernias often resolve spontaneously. Umbilical hernias in adults are largely acquired, and are more frequent in obese or pregnant women. Abnormal decussation of fibers at the linea alba may contribute. Incisional An incisional hernia occurs when the defect is the result of an incompletely healed surgical wound. When these occur in median laparotomy incisions in the linea alba, they are termed ventral hernias. These can be the most frustrating and difficult to treat, as the repair utilizes already attenuated tissue. Diaphragmatic , viewed from the front).

Higher in the abdomen, an (internal) diaphragmatic hernia results when part of the stomach or intestine protrudes into the chest cavity through a defect in the diaphragm. A hiatus hernia is a particular variant of this type, in which the normal passageway through which the esophagus meets the stomach ( esophageal hiatus) serves as a functional defect, allowing part of the stomach to (periodically) herniate into the chest. Hiatus hernias may be either sliding, in which the gastroesophageal junction itself slides through the defect into the chest, or non-sliding (also known as para-esophageal ), in which case the junction remains fixed while another portion of the stomach moves up through the defect. Non-sliding or para-esophageal hernias can be dangerous as they may allow the stomach to rotate and obstruct. Repair is usually advised. A congenital diaphragmatic hernia is a distinct problem, occurring in up to 1 in 2000 births, and requiring pediatric surgery.

Intestinal organs may herniate through several parts of the diaphragm, posterolateral (in Bochdalek's triangle, resulting in Bochdalek's hernia ), or anteromedial-retrosternal (in the cleft of Larrey/ Morgagni's foramen, resulting in Morgagni-Larrey hernia, or Morgagni's hernia). Other hernias Since many organs or parts of organs can herniate through many orifices, it is very difficult to give an exhaustive list of hernias, with all synonyms and eponyms. The above article deals mostly with visceral hernias, where the herniating tissue arises within the abdominal cavity. Other hernia types and unusual types of visceral hernias are listed below, in alphabetical order: ⇒Cooper's hernia: a femoral hernia with two sacs, the first being in the femoral canal, and the second passing through a defect in the superficial fascia and appearing almost immediately beneath the skin. ⇒Epigastric hernia: a hernia through the linea alba above the umbilicus.

⇒Hiatal hernia: a hernia due to short oesophagus - insufficient elongation - stomach is displaced into the thorax ⇒Littre's hernia: a hernia involving a Meckel's diverticulum. It is named after the French anatomist Alexis Littre (1658-1726). ⇒Lumbar hernia (Bleichner's Hernia): a hernia in the lumbar region (not to be confused with a lumbar disc hernia), contains the following entities: ♦Petit's hernia: a hernia through Petit's triangle (inferior lumbar triangle). It is named after French surgeon Jean Louis Petit (1674-1750). ♦Grynfeltt's hernia: a hernia through Grynfeltt-Lesshaft triangle (superior lumbar triangle). It is named after physician Joseph Grynfeltt (1840-1913). ⇒Maydl hernia: two adjacent loops of small intestine are within a hernial sac with a tight neck. The intervening portion of bowel WITHIN the abdomen is deprived of its blood supply and eventually becomes necrotic.

⇒Obturator hernia: hernia through obturator canal ⇒Pantaloon hernia: a combined direct and indirect hernia, when the hernial sac protrudes on either side of the inferior epigastric vessels ⇒Paraesophageal hernia ⇒Paraumbilical hernia: a type of umbilical hernia occurring in adults ⇒Perineal hernia: a perineal hernia protrudes through the muscles and fascia of the perineal floor. It may be primary but usually, is acquired following perineal prostatectomy, abdominoperineal resection of the rectum, or pelvic exenteration. ⇒Properitoneal hernia: rare hernia located directly above the peritoneum, for example, when part of an inguinal hernia projects from the deep inguinal ring to the preperitoneal space. ⇒Richter's hernia: a hernia involving only one sidewall of the bowel, which can result in bowel strangulation leading to perforation through ischaemia without causing bowel obstruction or any of its warning signs. It is named after German surgeon August Gottlieb Richter (1742-1812).

⇒Sliding hernia: occurs when an organ drags along part of the peritoneum, or, in other words, the organ is part of the hernia sac. The colon and the urinary bladder are often involved. The term also frequently refers to sliding hernias of the stomach. ⇒ Sciatic hernia: this hernia in the greater sciatic foramen most commonly presents as an uncomfortable mass in the gluteal area. Bowel obstruction may also occur. This type of hernia is only a rare cause of sciatic neuralgia. ⇒Spigelian hernia, also known as spontaneous lateral ventral hernia ⇒Sports hernia: a hernia characterized by chronic groin pain in athletes and a dilated superficial ring of the inguinal canal.

⇒Velpeau hernia: a hernia in the groin in front of the femoral blood vessels ⇒Amyand's Hernia: containing the appendix vermiformis within the hernia sac Characteristics Hernias can be classified according to their anatomical location: Examples include: ⇒ diaphragmatic hernias and hiatal hernias (for example, paraesophageal hernia of the stomach) ⇒ pelvic hernias, for example, obturator hernia ⇒ anal hernias ⇒ hernias of the nucleus pulposus of the intervertebral discs ⇒ intracranial hernias ⇒ Spigelian hernia Each of the above hernias may be characterized by several aspects: ⇒congenital or acquired: congenital hernias occur prenatally or in the first year(s) of life, and are caused by a congenital defect, whereas acquired hernias develop later on in life. However, this may be on the basis of a locus minoris resistentiae (Lat. place of least resistance) that is congenital, but only becomes symptomatic later in life, when degeneration and increased stress (for example, increased abdominal pressure from coughing in COPD) provoke the hernia.

⇒complete or incomplete: for example, the stomach may partially or completely herniate into the chest. ⇒ internal or external: external ones herniate to the outside world, whereas internal hernias protrude from their normal compartment to another (for example, mesenteric hernias). ⇒intraparietal hernia: hernia that does not reach all the way to the subcutis, but only to the musculoaponeurotic layer. An example is a Spigelian hernia. Intraparietal hernias may produce less obvious bulging, and may be less easily detected on clinical examination. ⇒bilateral: in this case, simultaneous repair may be considered, sometimes even with a giant prosthetic reinforcement. ⇒irreducible (also known as incarcerated): the hernial contents cannot be returned to their normal site with simple manipulation. If irreducible, hernias can develop several complications (hence, they can be complicated or uncomplicated): ⇒strangulation: pressure on the hernial contents may compromise blood supply (especially veins, with their low pressure, are sensitive, and venous congestion often results) and cause ischemia, and later necrosis and gangrene, which may become fatal.

⇒obstruction: for example, when a part of the bowel herniates, bowel contents can no longer pass the obstruction. This results in cramps, and later on vomiting, ileus, absence of flatus and absence of defecation. ⇒dysfunction: another complication arises when the herniated organ itself, or surrounding organs, start to malfunction(for example, sliding hernia of the stomach causing heartburn, lumbar disc hernia causing sciatic nerve pain, etc.). Causes Causes of hiatal hernia vary depending on each individual. Among the multiple causes, however, are the mechanical causes which include: improper heavy weight lifting, hard coughing bouts, sharp blows to the abdomen, tight clothing and incorrect posture. Also, if muscles are weakened due to poor nutrition, smoking, and overexertion, hernias are more likely to occur. Signs and symptoms Symptoms may not be present in some inguinal hernias while in some other hernias, including inguinal, they are. Symptoms and signs vary depending on the type of hernia. In the case of reducible hernias, you can often see and feel a bulge in the groin or in another abdominal area.

When standing, such bulge becomes more obvious. Besides the bulge, other symptoms include pain in the groin that may also include a heavy or dragging sensation, and in men, there is sometimes pain and swelling in the scrotum around the testicles area. Irreducible hernias or incarcerated hernias may be painful, but their most relevant symptom is that they cannot return to the abdominal cavity when pushed in. They may be chronic, although painless, and can lead to strangulation. Nausea, vomiting, or fever may occur in these cases due to bowel obstruction. Also, the hernia bulge in this case may turn red, purple or dark. Strangulated hernias are always painful and pain is followed by tenderness. Nausea and vomiting also may occur as well due to bowel obstruction. The patient may also experience fever. Also, the pressure caused on the hernia's surrounding tissues may extend into the scrotum causing pain and swelling. Treatment It is generally advisable to repair hernias quickly in order to prevent complications such as organ dysfunction, gangrene, multiple organ dysfunction syndrome, and death. Most abdominal hernias can be surgically repaired, and recovery rarely requires long-term changes in lifestyle.

Uncomplicated hernias are principally repaired by pushing back, or reducing, the herniated tissue, and then mending the weakness in muscle tissue (an operation called herniorrhaphy). If complications have occurred, the surgeon will check the viability of the herniated organ, and resect it if necessary. Modern muscle reinforcement techniques involve synthetic materials (a mesh prosthesis) that avoid over-stretching of already weakened tissue (as in older, but still useful methods). The mesh is either placed over the defect (anterior repair) or more preferably under the defect (posterior repair). At times staples are used to keep the mesh in place. These mesh repair methods are often called Tension Free repairs because, unlike older traditional methods, muscle is not pulled together under tension. Evidence based testing initially suggested that these Tension Free methods have the lowest percentage of recurrences and the fastest recovery period compared to older suture repair methods. However, prosthetic mesh usage seems to have a high incidence of infection with mesh usage becoming a study topic for the National Institutes of Health. Increasingly, some repairs are performed through laparoscopes .

Laparoscopic surgery is also referred to as minimally invasive surgery, which requires one or more small incisions for the camera and instruments to be inserted, as opposed to traditional open or microscopic surgery, which requires an incision large enough for the surgeon's hands to be inserted into the patient. The defensive and misleading term microscopic surgery refers to the magnifying devices used during open surgery. Many patients are managed through day surgery centers, and are able to return to work within a week or two, while intensive activities are prohibited for a longer period. Patients who have their hernias repaired with mesh often recover in a number of days. Surgical complications have been estimated to be up to 10%, but most of them can be easily addressed. They include surgical site infections, nerve and blood vessel injuries, injury to nearby organs, and hernia recurrence. Generally, the use of external devices to maintain reduction of the hernia without repairing the underlying defect (such as hernia trusses, trunks, belts, etc.), is not advised. Exceptions are uncomplicated incisional hernias that arise shortly after the operation (should only be operated after a few months), or inoperable patients.

It is essential that the hernia not be further irritated by carrying out strenuous labour. Complications Complications may arise post-operation, including rejection of the mesh that is used to repair the hernia. In the event of a mesh rejection, the mesh will very likely need to be removed. Mesh rejection can be detected by obvious, sometimes localised swelling and pain around the mesh area. Continuous discharge from the scar is likely for a while after the mesh has been removed. An untreated hernia may be complicated by: ⇒ Inflammation ⇒ Photos of Hernias HIATUS HERNIA A hiatus hernia or hiatal hernia is the protrusion (or herniation) of the upper part of the stomach into the thorax through a tear or weakness in the diaphragm. Classification There are two major kinds of hiatus hernia: ⇒ The most common (95%) is the sliding hiatus hernia, where the gastroesophageal junction moves above the diaphragm together with some of the stomach. ⇒ The second kind is rolling (or paraesophageal) hiatus hernia, when a part of the stomach herniates through the esophageal hiatus and lies beside the esophagus, without movement of the gastroesophageal junction.

It accounts for the remaining 5% of hiatus hernias. A third kind is also sometimes described, and is a combination of the first and second kinds. Signs and symptoms Hiatal Hernia has often been called the great mimic because its symptoms can resemble many disorders. For example, a person with this problem can experience dull pains in their chest, shortness of breath (caused by the hernia's effect on the diaphragm), and heart palpitations (due to irritation of the vagus nerve). In most cases however, a hiatal hernia does not cause any symptoms. The pain and discomfort that a patient experiences is due to the reflux of gastric acid, air or bile. While there are several causes of acid reflux, it does happen more frequently in the presence of hiatal hernia. Risk factors The following are risk factors that can result in a hiatus hernia. ⇒ Increased pressure within the abdomen caused by: ♦ Heavy lifting or bending over ♦ Frequent or hard coughing ♦ Obesity (extra weight pushes down on the abdomen increasing the pressure) ♦ Use of the sitting position for defecation (See epidemiology below) ⇒ Heredity ⇒ Drug use, such as cocaine.

⇒ Stress ⇒ Diaphragm weakness Diagnosis The diagnosis of a hiatus hernia is typically made through an upper GI series, endoscopy or High resolution manometry. Treatment In most cases, sufferers experience no discomfort and no treatment is required. However, when the hiatal hernia is large, or is of the paraesophageal type, it is likely to cause esophageal stricture and discomfort. Symptomatic patients should elevate the head of their beds and avoid lying down directly after meals until treatment is rendered. If the condition has been brought on by stress, stress reduction techniques may be prescribed, or if overweight, weight loss may be indicated. Medications that reduce the lower esophageal sphincter (or LES) pressure should be avoided. Antisecretory drugs like proton pump inhibitors and H 2 receptor blockers can be used to reduce acid secretion. Where hernia symptoms are severe and chronic acid reflux is involved, surgery is sometimes recommended, as chronic reflux can severely injure the esophagus and even lead to esophageal cancer. The surgical procedure used is called Nissen fundoplication.

In fundoplication, the gastric fundus (upper part) of the stomach is wrapped, or plicated, around the inferior part of the esophagus, preventing herniation of the stomach through the hiatus in the diaphragm and the reflux of gastric acid. The procedure is now commonly performed laparoscopically. With proper patient selection, laparoscopic fundoplication has low complication rates and a quick recovery. Complications include gas bloat syndrome, dysphagia (trouble swallowing), dumping syndrome, excessive scarring, and rarely, achalasia. The procedure sometimes fails over time, requiring a second surgery to make repairs. Prognosis A hiatus hernia per se does not cause any symptoms. The condition promotes reflux of gastric contents ( via its direct and indirect actions on the anti-reflux mechanism) and thus is associated with gastroesophageal reflux disease (GERD). In this way a hiatus hernia is associated with all the potential consequences of GERD - heartburn, esophagitis, Barrett's esophagus and esophageal cancer. However the risk attributable to the hiatus hernia is difficult to quantify, and at most is low.

Besides discomfort from GERD and dysphagia, hiatal hernias can have severe consequences if not treated. While sliding hernias are primarily associated with gastroesophageal acid reflux, rolling hernias can strangulate a portion of the stomach above the diaphragm. This strangulation can result in esophageal or GI tract obstruction and the tissue can even become ischemic and necrose. Another severe complication, although very rare, is a large herniation that can restrict the inflation of a lung, causing pain and breathing problems. Most cases are asymptomatic. Epidemiology Incidence of hiatal hernias increases with age; approximately 60% of individuals aged 50 or older have a hiatal hernia. Of these, 9% are symptomatic, depending on the competence of the lower esophageal sphincter (LES). 95% of these are sliding hiatus hernias, in which the LES protrudes above the diaphragm along with the stomach, and only 5% are the rolling type (paraesophageal), in which the LES remains stationary but the stomach protrudes above the diaphragm. People of all ages can get this condition, but it is more common in older people. According to Dr.

Denis Burkitt, Hiatus hernia has its maximum prevalence in economically developed communities in North America and Western Europe....In contrast the disease is rare in situations typified by rural African communities. Notes and references External links DIAPHRAGMATIC RUPTURE Diaphragmatic rupture (also called diaphragmatic injury or tear) is a tear of the diaphragm, the muscle across the bottom of the ribcage that plays a crucial role in respiration. Most commonly, acquired diaphragmatic tears result from physical trauma. Diaphragmatic rupture can result from blunt or penetrating trauma Diagnostic techniques include X-ray, computed tomography, and surgical techniques such as laparotomy. Diagnosis is often difficult because signs may not show up on X-ray, or signs that do show up appear similar to other conditions. Signs and symptoms included chest and abdominal pain, difficulty breathing, and decreased lung sounds. When a tear is discovered, surgery is needed to repair it. Injuries to the diaphragm are usually accompanied by other injuries, and they indicate that more severe injury may have occurred. The outcome often depends more on associated injuries than on the diaphragmatic injury itself.

Since the pressure is higher in the abdominal cavity than the chest cavity, rupture of the diaphragm is almost always associated with herniation of abdominal organs into the chest cavity, called traumatic diaphragmatic hernia. This herniation can interfere with breathing, and blood supply can be cut off to organs that herniate through the diaphragm, damaging them. Signs and symptoms Breath sounds on the side of the rupture may be diminished, respiratory distress may be present, and the chest or abdomen may be painful. Orthopnea, dyspnea which occurs when lying flat, may also occur, and coughing is another sign. In people with herniation of abdominal organs, signs of intestinal blockage or sepsis in the abdomen may be present. Bowel sounds may be heard in the chest, and shoulder or epigastric pain may be present. When the injury is not noticed right away, the main symptoms are those that indicate bowel obstruction. Causes The injury may be caused by blunt trauma, penetrating trauma, and by iatrogenic causes (as a result of medical intervention), for example during surgery to the abdomen or chest. Injury to the diaphragm is reported to be present in 8% of cases of blunt chest trauma.

In cases of blunt trauma, vehicle accidents and falls are the most common causes. Penetrating trauma has been reported to cause 12.3-20% of cases, but it has also been proposed as a more common cause than blunt trauma; discrepancies could be due to varying regional, social, and economic factors in the areas studied. Stab and gunshot wounds can cause diaphragmatic injuries. Clinicians are trained to suspect diaphragmatic rupture particularly if penetrating trauma has occurred to the lower chest or upper abdomen. Mechanism Although the mechanism is unknown, it is proposed that a blow to the abdomen may raise the pressure within the abdomen so high that the diaphragm bursts. Blunt trauma creates a large pressure gradient between the abdominal and thoracic cavities; this gradient, in addition to causing the rupture, can also cause abdominal contents to herniate into the thoracic cavity. Abdominal contents in the pleural space interfere with breathing and cardiac activity. They can interfere with the return of blood to the heart and prevent the heart from filling effectively, reducing cardiac output. If ventilation of the lung on the side of the tear is severely inhibited, hypoxemia (low blood oxygen) results. Usually the rupture is on the same side as an impact.

A blow to the side is three times more likely to cause diaphragmatic rupture than a blow to the front. Diagnosis Initially, diagnosis can be difficult, especially when other severe injuries are present; thus the condition is commonly diagnosed late. Chest X-ray is known to be unreliable in diagnosing diaphragmatic rupture; it has low sensitivity and specificity for the injury. Often another injury such as pulmonary contusion masks the injury on the X-ray film. Half the time, initial X-rays are normal; in most of those that are not, hemothorax or pneumothorax is present. However, there are signs detectable on X-ray films that indicate the injury. On an X-ray, the diaphram may appear higher than normal. Gas bubbles may appear in the chest, and the mediastinum may appear shifted to the side. A nasogastric tube from the stomach may appear on the film in the chest cavity; this sign is pathognomonic for diaphragmatic rupture, but it is rare. A contrast medium that shows up on X-ray can be inserted through the nasogastric tube to make a diagnosis.

The X-ray is better able to detect the injury when taken from the back with the patient upright, but this is not usually possible because the patient is usually not stable enough; thus it is usually taken from the front with the patient lying supine. Positive pressure ventilation helps keep the abdominal organs from herniating into the chest cavity, but this also can prevent the injury from being discovered on an X-ray. Computed tomography has an increased accuracy of diagnosis over X-ray, but no specific findings on a CT scan exist to establish a diagnosis. Although CT scanning increases chances that diaphragmatic rupture will be diagnosed before surgery, the rate of diagnosis before surgery is still only 31-43.5%. Another diagnostic method is laparotomy, but this misses diaphragmatic ruptures up to 15% of the time. Often diaphragmatic injury is discovered during a laparotomy that was undertaken because of another abdominal injury. Thoracoscopy is more reliable in detecting diaphragmatic tears than laparotomy and is especially useful when chronic diaphragmatic hernia is suspected. It is possible that the liver, which is situated in the right upper quadrant of the abdomen, cushions the diaphragm.

However, injuries occurring on the left side are also easier to detect in X-ray films. Half of diaphragmatic ruptures that occur on the right side are associated with liver injury. Injuries occurring on the right are associated with a higher rate of death and more numerous and serious accompanying injuries. Bilateral diaphragmatic rupture, which occurs in 1-2% of ruptures, is associated with a much higher death rate ( mortality) than injury that occurs on just one side. Treatment Since the diaphragm is in constant motion with respiration, and because it is under tension, lacerations will not heal on their own. Surgery is needed to repair a torn diaphragm. Most of the time, the injury is repaired during laparotomy. Other injuries, such as hemothorax, may present a more immediate threat and may need to be treated first if they accompany diaphragmatic rupture. Video-assisted thoracoscopy may be used. Prognosis In most cases, isolated diaphragmatic rupture is associated with good outcome if it is surgically repaired.

The death rate ( mortality) for diaphragmatic rupture after blunt and penetrating trauma is estimated to be 15-40% and 10-30% respectively, but other injuries play a large role in determining outcome. Complications A significant complication of diaphragmatic rupture is traumatic diaphragmatic herniation: organs such as the stomach that herniate into the chest cavity and may be strangulated, losing their blood supply. Herniation of abdominal organs is present in 3-4% of people with abdominal trauma who present to a trauma center. Epidemiology Diaphragmatic injuries are present in 1-7% of people with significant blunt trauma and an average of 3% of abdominal injuries. A high body mass index may be associated with a higher risk of diaphragmatic rupture in people involved in vehicle accidents. Thus, the mortality after a diagnosis of diaphragmatic rupture is 17%, with most deaths due to lung complications. Common associated injuries include head injury, injuries to the aorta, fractures of the pelvis and long bones, and lacerations of the liver and spleen. Associated injuries occur in over three quarters of cases.

History In 1579, Ambroise Paré made the first description of diaphragmatic rupture, in a French artillery captain who had been shot eight months before his death from complications of the rupture. Using autopsies, Paré also described diaphragmatic rupture in people who had suffered blunt and penetrating trauma. Reports of diaphragmatic herniation due to injury date back at least as far as the 17th century. Petit was the first to establish the difference between acquired and congenital diaphragmatic hernia, which results from a congenital malformation of the diaphragm. In 1888, Naumann repaired a hernia of the stomach into the left chest that was caused by trauma. References DIAPHRAGMATIC HERNIA Diaphragmatic hernia is a defect or hole in the diaphragm that allows the abdominal contents to move into the chest cavity. Treatment is usually surgical. The following types of diaphragmatic hernia exist: ⇒ Congenital diaphragmatic hernia A scaphoid abdomen ( sucked inwards ) may be the presenting symptom in a newborn. Diagnosis Diagnosis can be made by either CT or Xray.

References ⇒ Another helpful link is at THORACIC DIAPHRAGM : For other types of diaphragm, see Diaphragm. In the anatomy of mammals, the thoracic diaphragm, or simply the diaphragm, is a sheet of internal muscle that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity (heart, lungs & ribs) from the abdominal cavity and performs an important function in respiration. A diaphragm in anatomy can refer to other flat structures such as the urogenital diaphragm or pelvic diaphragm, but the diaphragm generally refers to the thoracic diaphragm. Other vertebrates such as amphibians and reptiles have diaphragms or diaphragm-like structures, but important details of the anatomy vary, such as the position of lungs in the abdominal cavity. Function The diaphragm functions in breathing. During inhalation, the diaphragm contracts, thus enlarging the thoracic cavity (the external intercostal muscles also participate in this enlargement). This reduces intra-thoracic pressure: In other words, enlarging the cavity creates suction that draws air into the lungs.

When the diaphragm relaxes, air is exhaled by elastic recoil of the lung and the tissues lining the thoracic cavity in conjunction with the abdominal muscles, which act as an antagonist paired with the diaphragm's contraction. The diaphragm is also involved in non-respiratory functions, helping to expel vomit, feces, and urine from the body by increasing intra-abdominal pressure, and preventing acid reflux by exerting pressure on the esophagus as it passes through the esophageal hiatus. In some non-human animals, the diaphragm is not crucial for breathing; a cow, for instance, can survive fairly asymptomatically with diaphragmatic paralysis as long as no massive aerobic metabolic demands are made of it. Anatomy The diaphragm is a dome-shaped musculofibrous septum that separates the thoracic from the abdominal cavity, its convex upper surface forming the floor of the former, and its concave under surface the roof of the latter. Its peripheral part consists of muscular fibers that take origin from the circumference of the inferior thoracic aperture and converge to be inserted into a central tendon.

The muscular fibers may be grouped according to their origins into three parts: There are two lumbocostal arches, a medial and a lateral, on either side. Innervation The diaphragm is innervated by the phrenic nerve which is formed from the cervical nerves C3, C4, and C5. A useful mnemonic to remember this is, C-3, 4, 5 keep the diaphragm alive Crura and central tendon At their origins the crura are tendinous in structure, and blend with the anterior longitudinal ligament of the vertebral column. The central tendon of the diaphragm is a thin but strong aponeurosis situated near the center of the vault formed by the muscle, but somewhat closer to the front than to the back of the thorax, so that the posterior muscular fibers are the longer. Openings in the Diaphragm The diaphragm is pierced by a series of apertures to permit of the passage of structures between the thorax and abdomen. Three large openings — the aortic, the esophageal, and the vena cava — and a series of smaller ones are described. .

A commonly used mnemonic to remember the level of the diaphragmatic apertures is this: Mnemonic ⇒Aortic hiatus = 12 letters = T12 ⇒Oesophagus = 10 letters = T10 ⇒Vena cava = 8 letters = T8 Another common mnemonic is: I(inferior vena cava) 8 (ate), 10 E (eggs), @(aorta) 12; I8 10E @12 Comparative anatomy and evolution The existence of some membrane separating the pharynx from the stomach can be traced widely among the chordates. Thus amphioxus possesses an atrium by which water exits the pharynx, which has been argued (and disputed) to be homologous to structures in ascidians and hagfishes. The urochordate epicardium separates digestive organs from the pharynx and heart, but the anus returns to the upper compartment to discharge wastes through an outgoing siphon. Thus the diaphragm emerges in the context of a body plan that separated an upper feeding compartment from a lower digestive tract, but the point at which it originates is a matter of definition.

Structures in fish, amphibians, reptiles, and birds have been called diaphragms, but it has been argued that these structures are not homologous. For instance, the alligator diaphragmaticus muscle does not insert on the esophagus and does not affect pressure of the lower esophageal sphincter. The lungs are located in the abdominal compartment of amphibians and reptiles, so that contraction of the diaphragm expels air from the lungs rather than drawing it into them. In birds and mammals, lungs are located above the diaphragm. The presence of an exceptionally well-preserved fossil of Sinosauropteryx, with lungs located beneath the diaphragm as in crocodiles, has been used to argue that dinosaurs could not have sustained an active warm-blooded physiology, or that birds could not have evolved from dinosaurs. An explanation for this state of affairs is that, when lungs originated beneath the diaphragm, but as the demands for respiration increased in warm-blooded birds and mammals, natural selection came to favor the parallel evolution of the herniation of the lungs from the abdominal cavity in both lineages.

Variations The sternal portion of the muscle is sometimes wanting and more rarely defects occur in the lateral part of the central tendon or adjoining muscle fibers. Pathology The right crus of the diaphragm is part of the lower esophageal sphincter (LES), which separates the thoracic and abdominal parts of the esophagus. A hiatal hernia, in which the abdominal esophagus or even the fundus of the stomach rises up through the esophageal hiatus into the thoracic cavity, can result from a tear or weakness in the diaphragm. Weakness may also result from injury to the neck at levels C3, C4, C5 which can result in altered tone of either half of the diaphragm. Both general weakness of the LES and hiatal hernia can cause acid reflux, also known as gastroesophageal reflux disease u(GERD). If the diaphragm is struck, or otherwise spasms, breathing will become difficult. This is called having the wind knocked out of you. Hiccoughs are involuntary intermittent sudden contractions of the diaphragm.

Gas inferior to the diaphragm in a human (or posterior in a four-footed creature) may be pneumoperitoneum, which can be a sign of serious pathology. Additional images External links PHRENIC NERVE The phrenic nerve originates mainly from the 4th cervical nerve, but also receives contributions from the 5th and 3rd cervical nerves (C3-C5) in humans. The phrenic nerves contain motor, sensory, and sympathetic nerve fibers. These nerves provide the only motor supply to the diaphragm as well as sensation to the central tendon. In the thorax, each phrenic nerve supplies the mediastinal pleura and pericardium. The contribution of the C5 nerve to the phrenic nerve may be derived from an accessory phrenic nerve (Fig. 8.10). Frequently, it is a branch of the nerve to the subclavius. If present, the accessory phrenic nerve lies lateral to the main nerve and descends posterior and sometimes anterior to the subclavian vein. The accessory phrenic nerve joins the phrenic nerve either in the root of the neck or in the thorax.

Path The phrenic nerve descends obliquely with the IJV across the anterior scalene, deep to the prevertebral layer of deep cervical fascia and the transverse cervical and suprascapular arteries. On the left; the phrenic nerve crosses anterior to the first part of the subclavian artery. On the right; it lies on the anterior scalene muscle and crosses anterior to the 2nd part of the subclavian artery. On both sides, the phrenic nerve runs posterior to the subclavian vein and anterior to the internal thoracic artery as it enters the thorax. Found in the middle mediastinum, both phrenic nerves run from C3, C4 and C5 along the anterior scalene muscle deep to the carotid sheath. ⇒ The right phrenic nerve passes over the brachiocephalic artery, posterior to the subclavian vein, and then crosses the root of the right lung anteriorly and then leaves the thorax by passing through the vena cava hiatus opening in the diaphragm at the level of T8. The right phrenic nerve passes over the right atrium.

⇒ The left phrenic nerve passes over the pericardium of the left ventricle and pierces the diaphragm separately. On both sides the phrenic nerve runs posterior to the subclavian vein and anterior to the internal thoracic artery as it enters the thorax. Both of these nerves supply motor fibres to the diaphragm and sensory fibres to the fibrous pericardium, mediastinal pleura, and diaphragmatic peritoneum. The pericardiacophrenic arteries and veins travel with their respective phrenic nerves. The contribution of the 5th cervical nerve, may stem from an accessory phrenic nerve. Most often it is a branch of the nerve to the subclavius and may contain numerous phrenic nerve fibers. If the accessory phrenic nerve is present it lies lateral to the main nerve and descends posterior and occasionally inferior to the subclavian vein. The accessory phrenic nerve connects to the phrenic nerve in the thorax or the root of the neck. Clinical relevance Pain arising from structures served by the phrenic nerve is often referred to other somatic regions served by spinal nerves C3-C5.

For example, a subphrenic abscess beneath the right diaphragm might cause a patient to feel pain in the right shoulder (Kehr's sign). Irritation of the phrenic nerve (or the tissues supplied by it) leads to the hiccough reflex. A hiccough is a spasmodic contraction of the diaphram, which pulls air against the closed folds of the larynx. The phrenic nerve must be identified during thoracic surgery and preserved. It passes anterior to the hilum of the corresponding lung, and therefore can be identified easily. Severing the phrenic nerve, or a phrenectomy, will paralyse that half of the diaphragm. Breathing will be made more difficult but will continue provided the other nerve is intact. Fortunately, the phrenic nerve arises from the neck (C3-C5) and innervates the diaphragm, which is much lower. Hence, patients who suffer spinal cord injuries below the neck are still able to breathe effectively, despite any paralysis of the lower limbs. Additional images ⇒ - Left side of the mediastinum. ⇒ - Diagram of the cervical plexus.

GETTING THE WIND KNOCKED OUT OF YOU Getting the wind knocked out of you is a phrase and a commonly used idiom that mainly refers to a kind of diaphragm spasm that occurs when sudden force is applied to the abdomen which puts pressure on the solar plexus. It results in a temporary paralysis of the diaphragm that makes it difficult to breathe for a short period of time. It can also occur from a strong blow to the back. When the abdomen is struck, a large difference in pressure occurs across the diaphragm. The diaphragm then stretches, which also stretches the diaphragm's nerves. The resulting mechanical force puts the diaphragm into a muscle spasm, comparable to having a charley horse in the leg. It takes a few seconds for the diaphragm to relax again before breathing can resume normally. Martial artists are often taught to breathe out heavily when struck in the stomach, to minimize this effect. Often, the laryngeal muscles contract during diaphragm spasm producing an inspiratory sound known as stridor which can be heard for several cycles as breathing resumes.

Singultus, commonly known as the hiccups, is also a form of diaphragm spasm, although much milder. A singultus episode impairs voluntary breathing control for brief moments (measured in milliseconds) rather than for several seconds. It may also be referred to as Rat Gut, getting winded or just winded. See also References IRON LUNG An iron lung is a machine that enables a person to breathe when normal muscle control has been lost or the work of breathing exceeds the person's ability. It is a form of medical ventilator. Properly, it is called a negative pressure ventilator. Method and use Humans, like many other organisms, breathe by negative pressure breathing: the rib cage expands and the diaphragm pulls down, expanding the chest cavity. This causes the pressure in the chest cavity to decrease, and the lungs expand to fill the space. This, in turn, causes the pressure of the air inside the lungs to fall (it becomes negative, relative to the atmosphere), and air flows into the lungs from the atmosphere: inhalation. When the chest cavity is contracted, the reverse happens and the person exhales.

If a person loses part or all of the ability to control the muscles involved, breathing becomes difficult or impossible. The person using the iron lung is placed into the central chamber, a cylindrical steel drum. A door allowing the head and neck to remain free is then closed, forming a sealed, air-tight compartment enclosing the rest of the person's body. Pumps that control airflow periodically decrease and increase the air pressure within the chamber, and particularly, on the chest. When the pressure is below that within the lungs, the lungs expand and atmospheric pressure pushes air from outside the chamber in via the person's nose and airways to keep the lungs filled; when the pressure goes above that within the lungs, the reverse occurs, and air is expelled. In this manner, the iron lung mimics the physiological action of breathing: by periodically altering intrathoracic pressure, it causes air to flow in and out of the lungs. The iron lung is a form of non-invasive therapy. Invention and progression The machine was invented by Phillip Drinker and Louis Agassiz Shaw.

Originally for treatment of coal gas poisoning, it found its most famous use in the mid-1900s when victims of poliomyelitis (more commonly known as polio), stricken with paralysis (including of the diaphragm, the cone shaped muscle at the bottom of the rib-cage whose action controls intrathoracic pressure), became unable to breathe, and were placed in these steel chambers to survive. The first iron lung was used on October 12, 1928 at Children's Hospital, Boston, on a child unconscious from respiratory failure; her dramatic recovery, within seconds of being placed within the chamber, did much to popularize the Drinker Respirator. In 1931, inveterate tinkerer John Haven Jack Emerson unveiled a less expensive iron lung. Drinker and Harvard promptly sued Emerson for patent violations, which proved unwise. In the subsequent legal battles Emerson demonstrated that every aspect of Drinker's patents had been patented by others at earlier times. Emerson won the case, and Drinker's patents were declared invalid.

Entire hospital wards were filled with rows of iron lungs at the height of the polio outbreaks of the 1940s and 1950s. With the success of the worldwide polio vaccination programs which have virtually eradicated new cases of the disease, and the advent of modern ventilators that control breathing via the direct intubation of the airway, the use of the iron lung has sharply declined. Modern usage Positive pressure ventilation systems are now more common than negative pressure systems. Positive pressure ventilators work by blowing air into the patient's lungs via intubation through the airway; they were used for the first time in Blegdams Hospital, Copenhagen, Denmark during a polio outbreak in 1952. It proved a success and soon superseded the iron lung throughout Europe. The iron lung now has a marginal place in modern respiratory therapy. Most patients with paralysis of the breathing muscles use modern mechanical ventilators that push air into the airway with positive pressure. These are generally efficacious and have the advantage of not restricting patients' movements or caregivers' ability to examine the patients as significantly as an iron lung does.

However, negative pressure ventilation is a truer approximation of normal physiological breathing and results in more normal distribution of air in the lungs. It may also be preferable in certain rare conditions, such as Ondine's curse, in which failure of the medullary respiratory centers at the base of the brain result in patients having no autonomic control of breathing. At least one reported polio patient, Dianne Odell, had a spinal deformity that caused the use of mechanical ventilators to be contraindicated. Martha Mason of Lattimore, North Carolina died on May 4, 2009, after spending 60 of her 71 years in an iron lung. On the 30th of October 2009, June Middleton, an Australian woman who entered the Guinness book of records as the person who spent the longest time in an iron lung died aged 83 in Melbourne, Australia. Biphasic Cuirass Ventilation is a modern development of the iron lung, consisting of a wearable rigid upper-body shell (a cuirass) which functions as a negative pressure ventilator.

Literature ⇒ Martha Mason, a polio survivor, penned a best-selling memoir, Breath, about her life inside an iron lung. ⇒ June Opie describes her time in an iron lung during recovery from polio, in her novel Over My Dead Body ⇒ Margaret Atwood mentions an iron lung in her book Cat's Eye ⇒ Jacob Appel's story Long Term addresses the disposal of iron lungs after their occupants have died. ⇒ Peg Kehret mentions her use of an iron lung in her autobiographical book, ⇒ Elizabeth Berg shares a fictionalization of the true story of Pat Raming, the first woman to give birth to baby while in an iron lung, in her book, We are all Welcome Here. 2006.

Question: What machine, that enables a person to breathe when the work of breathing exceeds their ability to do so, was invented by Phillip Drinker and Louis Agassiz Shaw in 1928 and improved upon by John Haven "Jack" Emerson in 1931?
Answer: Iron lung