Muscle separating the chest and abdomen
Diaphragm | Definition, Function, & Location
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Anatomy, Thorax, Diaphragm - StatPearls
Kanwal Naveen S.
Bains; Sarang Kashyap; Sarah L. Lappin.
Author Information and Affiliations
Last Update: July 25, 2022.
Introduction
The diaphragm in the thorax is called the thoracic diaphragm and serves as an important anatomical landmark that separates the thorax, or chest, from the abdomen. It functions during breathing when it contracts to enlarge the thoracic cavity and reduce the intrathoracic pressure so that lungs may expand and fill their alveoli with air. It is a dome-shaped muscle and tendon that functions as the main muscle of respiration and is essential to the breathing process. It is a fibromuscular sheet that has a convex upper surface that forms the floor of the thoracic cavity and a concave under surface to form the roof of the abdominal cavity. The esophagus, phrenic, and vagus nerves, descending aorta, and inferior vena cava pass through the diaphragm between the thoracic and abdominal cavities. The diaphragm is asymmetric with the left side slightly more inferior than the right, chiefly because of the presence of the liver located on the right.
The left side may also be partially inferiorly located because of the push by the heart.[1],[2]
Structure and Function
Functions of the Diaphragm
Muscle of Inspiration
The diaphragm pulls its central tendon down during contraction and then increases the vertical diameter of the thorax. This increases the negative pressure inside the thoracic cavity, which draws in air. Thus, the diaphragm is the most important muscle used in inspiration. During inhalation, the diaphragm contracts and is pushed inferiorly into the abdominal cavity where it appears flat. Simultaneously the external intercostal muscles located in between the ribs raise the anterior chest wall like the handles of a bucket. This results in the chest cavity becoming larger and wider, which allows air in from the outside. During exhalation, the rib cage and chest wall start to sag and revert to the original position. At the same time, there is relaxation and elevation of the diaphragm.
This motion forces the air within the lungs to push out of the body.[2],[3]
Muscle of Abdominal Straining
The contraction of the diaphragm will assist in the contraction of the muscles of the anterior abdominal wall in raising the intra-abdominal pressure will normal processes like micturition, defecation, and parturition.
Weightlifting Muscle
When a person takes and holds a deep breath, the diaphragm will assist the muscles of the anterior abdominal wall to raise the intra-abdominal pressure. This maneuver is also called as Valsalva maneuver and is used to augment heart murmurs and classify them whether they are clinically right-sided or left-sided.
Thoracoabdominal Pump
When people breathe in, the diaphragm descends, which decreases the intrathoracic pressure and improves the intra-abdominal pressure. This compresses the blood in the inferior vena cava (IVC) and forces it upward into the right atrium and helps to fill the heart.
When abdominal lymph vessels are also compressed, its passage upward within the thoracic duct is aided by the negative intrathoracic pressure. Furthermore, valves in the thoracic duct prevent the backflow of the lymph in the thoracic duct.
Embryology
Diaphragm Formation
Septum transversum
Pleuro-peritoneal membrane
Mesentery of esophagus
Mesoderm of the body wall
Insertion
The diaphragm inserts into a central tendon. The top surface of the tendon is partially connected to the lower surface of the fibrous pericardium. Muscle fibers arising from the right crus traverse up on the left side and encircle the orifice of the esophagus in a sling-like loop. These fibers act as a sphincter and likely assist in preventing the regurgitation of the stomach contents into the thoracic part of the esophagus.[4]
Origin of Diaphragm
Sternal
The sternal part originates as 2 fleshy slips from the back of the xiphoid process.
Costal
The costal part originates from inner surfaces of the cartilages, adjacent parts of the lower sixth ribs on each side. It interdigitates with transversus abdominis.
Lumbar
The medial lumbocostal arch is a tendinous arch in fascia covering psoas major. Medially, it attaches to the side of the body of vertebra L1. Laterally, it connects to the front of the transverse process of vertebra L1.
The lateral lumbocostal arch is a tendinous arch in fascia covering the upper part of quadratus lumborum. Medially, attach to the front of the transverse process of vertebra L1. Laterally, it connects to the lower border of the 12th rib.
The right crus arises from the anterolateral surface of the bodies of the upper three lumbar vertebrae and also the intervening intervertebral disc
The left crus arises from the corresponding parts of the upper 2 lumbar vertebrae.
Medial margin of two crura forms a tendinous arc across the front of the aorta called the median arcuate ligament.
Blood Supply and Lymphatics
Major Arteries Supplying the Diaphragm
Musculophrenic artery branch of the internal thoracic artery
Superior phrenic artery branch of the aorta
Lower five intercostal arteries and subcostal artery
Inferior phrenic artery
Nerves
Motor Nerve Supply
Right and left phrenic nerves (C3 through C5)
Sensory Nerve Supply
The phrenic nerve innervates the parietal pleura and peritoneum covering the central surfaces of the diaphragm. The lower 6 intercostal nerves supply the periphery of the diaphragm.
When the diaphragm contracts, the large-sized myelinated phrenic afferents fire. On the other hand, the smaller diameter nerves continue to discharge throughout the respiratory cycle. It is now well established that activation of both non-myelinated and myelinated phrenic sensory nerves modulate respiratory output during each breathing cycle.
However, the activation of the phrenic afferents does increase significantly as the diaphragm continues to work and develops fatigue. Once the phrenic afferents are activated, they also modulate the sympathetic motor outflow. Furthermore, the phrenic afferents also contribute to somatosensation of the diaphragm and make one aware of the sensation of breathing while awake. The exact influence of the spinal and supraspinal nerves and synapses between the non-myelinated and myelinated phrenic nerves is not known.
The use of deep muscle training contributed to a significant change in the position of the body in the sagittal plane and the increase in the amplitude of breathing.[5]
Muscles
One can find the origins of the diaphragm along the lumbar vertebrae of the spine and the inferior border of the ribs and sternum.
The superior diaphragm origin is continuous from the xiphoid process anteriorly to lower 6 costal cartilages of the thorax laterally and first 2 lumbar vertebrae posteriorly.
The musculoskeletal fibers radiate from all angles to the center of the body and converge into a central tendon which is the inferior attachment or muscular skeletal point.
The diaphragm has a dome-like structure with the peripheral segment attached to the chest wall and abdominal cavity. The muscle fibers from these attachments converge in a central tendon, which forms the crest of the dome. The periphery of the diaphragm is made of strong muscular fibers that have their origin from the surroundings of the inferior thoracic aperture. These muscle fibers than converge and insert into the central tendon.
Surgical Considerations
Diaphragmatic Hernia
A diaphragmatic hernia is a congenital disability that occurs when one or more of a person's abdominal organs (stomach, spleen, liver, intestines) move upward into the chest through a defect in the diaphragm. It is usually congenital but can be acquired. Congenital hernias are considered a medical emergency and require prompt surgery.
[6]
Congenital Diaphragmatic Hernia (CDH)
A CDH is an abnormal development of the diaphragm during fetal life. The herniation leads to the passage of one or other abdominal organ in the chest leading to the pulmonary hypoplasia which is usually unilateral. The most common subtype of congenital diaphragmatic hernias is Bochdalek Hernia. Other types include Morgagni a hernia, diaphragm eventration, and central tendon defects of the diaphragm.
Acquired Diaphragmatic Hernia (ADH)
An ADH happens due to penetrating or blunt injury. Falls and motor vehicle accidents are major causes of blunt injury while stabs and gunshot wounds lead to penetrating injuries. Penetrating injuries are the more common cause than the blunt injuries as a cause of the diaphragmatic rupture. Further, there can be accidental damage to the diaphragm from the surgical causes. Infrequently, a diaphragmatic hernia may result without any identifiable cause and remain undiagnosed for an undetermined amount of time, until the herniation of abdominal organs in the chest start to cause symptoms.
[7]
Treatment
Both acquired, and congenital diaphragmatic hernias usually require immediate surgery. Surgery requires the return of the abdominal organs from the chest cavity back into their original location in the abdominal cavity. The diaphragm should be repaired with staples or permanent sutures with or without a prosthetic patch.
Clinical Significance
The diaphragm has 3 major openings and 5 minor openings.
Major
The vena caval trunk lies at the level of the T8 vertebra in the central tendon. It allows passage of Inferior vena cava and some branches of the right phrenic nerve.
The esophageal hiatus lies at the level of the T10 vertebra in a sling of muscle fibers derived from the right crus at the left of the median plane. It allows passage of esophagus, the right and left vagus trunks, the esophageal branches of the left gastric vessels, and the lymph vessels.
The aortic hiatus lies anterior to the body of the T12 vertebra between the crura.
It allows passage of aorta, thoracic duct, and azygos vein.
Minor
The lesser aperture of right crus (permits lesser and greater splanchnic nerves)
The lesser aperture of left crus (permits hemiazygous vein; and lesser and greater splanchnic nerves)
The sympathetic trunk runs posteriorly below the medial lumbocostal arches.
Foramen of Morgagni is found in the areolar tissue between the sternal and costal part of diaphragm contains the superior epigastric branch of the internal thoracic artery and the lymphatics of the abdominal wall.
The medial and lateral lumbocostal arches can contain areolar tissue that, when present, separates the superior and posterior surface of a kidney from the pleura.
The figure below shows the openings in the diaphragm: A=vena cava, B=esophagus, C=aorta. The muscular diaphragm surrounds the central tendon in the periphery.
Other Issues
The diaphragm has many other roles besides respiration. It acts as a barrier between the thoracic and abdominal cavity and prevents herniation of abdominal organs into the chest cavity.
Both penetrating and blunt trauma can injure the diaphragm. A tear or rupture of the diaphragm is often a difficult diagnosis. Options for diagnosis include laparoscopy, thoracoscopy or a CT scan. Irrespective of the size of the tear, the muscle must be repaired as soon as possible to prevent herniation of abdominal organs.
The diaphragm is also involved in hiccups. When the muscle is irritated, it can result in sudden contractions which can be uncomfortable. Most hiccups are short-lived, but in rare cases, hiccups may last for a day. If the hiccups persist, they can interfere with breathing.
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Figure
Diaphragm and its apertures.
Image courtesy S Bhimji MD
References
- 1.
Oliver KA, Ashurst JV. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Jul 25, 2022. Anatomy, Thorax, Phrenic Nerves. [PubMed: 30020697]
- 2.
Bordoni B, Purgol S, Bizzarri A, Modica M, Morabito B. The Influence of Breathing on the Central Nervous System. Cureus. 2018 Jun 01;10(6):e2724. [PMC free article: PMC6070065] [PubMed: 30083485]
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McCool FD, Manzoor K, Minami T. Disorders of the Diaphragm. Clin Chest Med. 2018 Jun;39(2):345-360. [PubMed: 29779594]
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Sefton EM, Gallardo M, Kardon G. Developmental origin and morphogenesis of the diaphragm, an essential mammalian muscle. Dev Biol. 2018 Aug 15;440(2):64-73. [PMC free article: PMC6089379] [PubMed: 29679560]
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Fayssoil A, Behin A, Ogna A, Mompoint D, Amthor H, Clair B, Laforet P, Mansart A, Prigent H, Orlikowski D, Stojkovic T, Vinit S, Carlier R, Eymard B, Lofaso F, Annane D.
Diaphragm: Pathophysiology and Ultrasound Imaging in Neuromuscular Disorders. J Neuromuscul Dis. 2018;5(1):1-10. [PMC free article: PMC5836400] [PubMed: 29278898]- 6.
Petrosyan M, Shah AA, Chahine AA, Guzzetta PC, Sandler AD, Kane TD. Congenital paraesophageal hernia: Contemporary results and outcomes of laparoscopic approach to repair in symptomatic infants and children. J Pediatr Surg. 2019 Jul;54(7):1346-1350. [PubMed: 30072216]
- 7.
Newbury A, Dorfman JD, Lo HS. Imaging and Management of Thoracic Trauma. Semin Ultrasound CT MR. 2018 Aug;39(4):347-354. [PubMed: 30070227]
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Login form | You are in the section→Speech therapist→Methodological materials→ Agrammatism Updated: June 20, 2022 What is diaphragmatic breathing? Respiratory organs. Image from Wikipedia There are two main types of breathing: thoracic and diaphragmatic. To play musical instruments that involve breathing (vargans, flutes and other wind instruments), as well as all types of vocals, you need to breathe with a diaphragm or, as they say, “breathe with your stomach”. In fact, of course, we breathe not with the stomach, but with the lungs, but the air is pumped into them with the help of the diaphragm. The diaphragm is such a large muscular partition that separates the organs of the abdominal and chest cavities. When it descends, an area of low pressure is created in the lungs and air is sucked into them, and the stomach, accordingly, sticks out. Diaphragmatic breathing is the most natural and correct breathing for a person. We all start breathing correctly from birth, but then, as we grow older, we acquire various complexes, fears, muscle clamps, we are tormented by stress. As a result, the diaphragm is also clamped and the person begins to breathe through the chest. When we breathe through the chest, the air fills only the upper sections of the lungs, there is less oxygen. Our health is weakening, the brain starts to work worse. Therefore, it is very important to learn how to breathe correctly again. For this, there are simple exercises. Diaphragmatic breathing exercises In the early stages, when returning to diaphragmatic breathing, one must be careful. Do not try to breathe too deeply and too often, this can lead to hyperventilation of the lungs, cause dizziness and loss of consciousness. However, if you practice without fanaticism, but regularly, then your body will be very grateful to you. We wish you good luck in getting back to proper healthy breathing! | Calendar
AnatomySubject: Muscles of the chest and abdomen. Plan:
The muscles of the chest , like the muscles of the back, are divided into two groups: superficial muscles that have moved in the process of development from the upper limb, and deep - own muscles. Superficial muscles of the chest The pectoralis major muscle (m. pectoralis major) starts from the medial part of the clavicle, handles of the sternum and cartilage of the upper five to six ribs, attached to the crest greater tubercle of the humerus. Function: lowers the raised arm and pulls towards the sternum, lowered arm rotates inward. With a fixed upper limb, it can participate in raising the ribs (auxiliary respiratory muscle). The pectoralis minor (m. pectoralis minor) starts from the III—V ribs, attached to the coracoid process of the scapula. Function: Lowers the shoulder girdle. With a fixed upper limb, raises the ribs (auxiliary respiratory muscle). The subclavian muscle (m. subclavius) starts from the clavicle, is attached to the 1st rib. Function: pulls the collarbone down. Serratus anterior (m. serratus anterior) begins with teeth from the top nine ribs, attached to the medial edge of the scapula. Function: rotates the scapula, shifting its lower angle forward, while abducting the hand above the horizontal line. With a fixed upper limb, it can lift ribs (auxiliary respiratory muscle). Muscles of the chest External intercostal muscles (mm. intercostales externi) fill the intercostal gaps from the spinal column to the costal cartilages. They each start from the lower edge of the overlying rib, are directed from above obliquely down and from back to front, attached to the upper edge of the underlying rib. Function: Raise the ribs. Internal intercostal muscles (mm. intercostales interni) lie under the previous and have the opposite direction of muscle bundles. They fill the intercostal intervals from the sternum to the corners of the ribs. Beginning at the top of the underlying ribs are attached to the lower edge of the overlying rib. Function: ribs are lowered. The muscles that lift the ribs (mm. levatores costarum) are located next to the chest section of the spinal column under the muscle that straightens the spine. Start from transverse processes of the VII cervical and upper thoracic vertebrae, go obliquely down and laterally, attached to the corners of the ribs. Function: lift, ribs. Diaphragma (diaphragma) - chest obstruction (studied together with the muscles chest). There are triangular gaps between the parts of the diaphragm, where there are no muscle fibers; This costosternal and costal-lumbar triangles. The diaphragm is a respiratory muscle. When she cuts down, her dome flattens (the volume of the chest increases - inhalation occurs), and when relaxation, it rises and takes the form of a dome (the volume of the chest decreases - exhalation occurs). Breast fasciae. There are thoracic and intrathoracic fasciae. Thoracic fascia has two sheets - superficial and deep. surface leaf covers the outside of the pectoralis major and serratus anterior muscles; deep leaf located under the pectoralis major muscle. In the region of the pectoralis minor and subclavian muscles the thickened section of the deep leaf is called the clavicular-thoracic fascia. The abdominal muscles play a dual role. On the one hand, they participate in body movements (flexing the body, turning it to the sides, lowering the ribs), on the other - when they contract, they act as an abdominal press: they change the volume abdominal cavity and intra-abdominal pressure. As abdominal muscles, these muscles participate in the emptying of the bladder (urination), intestines (defecation), and in women are also in the act of childbirth. The abdominal muscles form the anterior, lateral and partially posterior walls of the abdominal cavity. The bundles of fibers of different muscles go in mutually intersecting directions, which gives greater strength to the walls of the abdomen. The external oblique muscle of the abdomen (m. obliquus externus abdominis) starts from eight lower ribs with eight teeth, goes obliquely from top to bottom, from back to front in the same direction, as the external intercostal muscles; attaches to the iliac crest bones. In the medial direction, the muscle passes into a wide aponeurosis, which the midline connects to the aponeurosis of the opposite side. bottom edge aponeurosis folds back and spreads from the anterior superior spine ilium to the tubercle of the pubic bone, forming the inguinal ligament (lower wall channel of the same name). The internal oblique muscle of the abdomen (m. obliquus internus abdomi-nis) lies under the previous one. It starts from the iliac crest and from the lateral 2/3 of the inguinal ligament, attached to the lower edge of the XII, XI, X ribs; the course of the fibers corresponds to the direction internal intercostal muscles. In the medial direction, the muscle passes into the aponeurosis, which in the midline fuses with the aponeurosis of the opposite side. The transverse abdominal muscle (m. transversus abdominis) lies under the internal oblique muscle. It starts from the inner surface of the six lower ribs, the lumbar-thoracic fascia, iliac crest, lateral third of the inguinal ligament. Muscle fibers go to transverse direction, pass into the aponeurosis, which fuses with aponeurosis of the opposite side. The rectus abdominis (m. rectus abdominis) lies to the side of the midline, between aponeuroses of the oblique and transverse muscles of the abdomen, forming a vagina for it. It starts from the cartilages of the V-VIII ribs and the xiphoid process of the sternum, attached to the pubic bone. The rectus abdominis sheath has anterior and back plate. The anterior plate in the upper section is formed by an aponeurosis the external oblique muscle of the abdomen and the anterior leaflet of the aponeurosis of the internal oblique muscle abdomen (the aponeurosis of this muscle bifurcates at the lateral edge of the rectus muscle). rear the vaginal plate at this level is formed by the posterior leaf of the aponeurosis of the internal oblique muscle of the abdomen and aponeurosis of the transverse muscle. The quadratus lumborum (m. quadratus lumborum) is located on the back wall of the cavity belly. Originates from the iliac crest and inserts on the 12th rib transverse processes of the lumbar vertebrae. With unilateral contraction, it participates in lateral flexion of the lumbar spine, and with bilateral contraction - in its extension. Abdominal fasciae. Abdominal fascia three: superficial, own and intra-abdominal. The superficial fascia lies in the subcutaneous adipose tissue, well expressed in the lower abdomen, where it divides the fiber into layers. Inguinal canal (canalis inguinalis) is a gap in the lower part of the anterior abdominal wall, through which the seminal cord, and in women - a round ligament of the uterus. The inguinal canal has four walls: anterior - aponeurosis of the external oblique abdominal muscle, posterior - transverse fascia, upper - free lower edge of the internal oblique and transverse muscles abdomen and lower - the groove of the inguinal ligament. The area of the inguinal canal is one of the weak points of the anterior abdominal wall, since in this area, the abdominal wall consists only of the aponeurosis of the external oblique muscle abdomen and transverse fascia. The weak points of the anterior abdominal wall also include the white line of the abdomen and the umbilical ring. The white line (linea alba) of the abdomen is between the right and left straight sheaths abdominal muscles from the xiphoid process of the sternum to the pubic symphysis. She consists of intertwined tendon fibers of the aponeuroses of the external oblique, internal oblique and transverse abdominal muscles on both sides. The upper section of the white line is wider, but thinner than the lower one and may be the site of hernia formation (hernia of the white line). The umbilical ring (annulus umbilicalis) is approximately in the middle of the white lines. Security questions:
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ОБРАЗОВАНИЕ 
When we breathe through the diaphragm, much more air is drawn into our lungs and our body receives more oxygen. 
It is useful when doing this exercise to close your eyes to cut off another source of sensations. 
RF 
This is a flat, thin muscle that has the shape of a dome; she closes the bottom chest opening. The muscle bundles of the diaphragm start from the xiphoid process of the sternum, lower six pairs of ribs and lumbar vertebrae and are woven into tendon stretching, which is the central part of the diaphragm, - tendon center. Depending on the origin of muscle fibers in the diaphragm There are three parts: sternum, costal and lumbar. The lumbar region has two large holes - aortic and esophageal, and in the tendon center on the right - opening of the inferior vena cava. 
These are the weak points of the diaphragm: in they may develop diaphragmatic hernias. 
Allocate such a fascia covering the external intercostal muscles and ribs (external intercostal fascia). Intrathoracic fascia lines the inner surface of the chest cells (thoracic cavity), including the upper surface of the diaphragm. 
They also take part in the act of breathing. 
Below the navel 4-5 cm) aponeuroses all three muscles pass in front of the rectus muscle, forming the anterior plate of its vagina; the posterior plate is represented only by the transverse fascia. 
own fascia has three sheets covering the external oblique, internal oblique and transverse muscles belly. The intra-abdominal fascia lines the inside of the abdominal wall. Her sections covering the lower surface of the diaphragm, the iliac muscle (refers to the muscles pelvis) and the transverse abdominal muscle, received the corresponding names: lower diaphragmatic fascia, iliac fascia and transverse fascia. 
The channel has two openings: surface inguinal ring and deep inguinal ring. Superficial inguinal ring limited fibers of the aponeurosis of the external oblique muscle of the abdomen, which, separating, form two legs: lateral (attached to the pubic tubercle) and medial (attached to pubic symphysis). From above, the ring is closed by interpeduncular fibers, and from below - bent ligament. The deep inguinal ring is located on the inner (back) surface of the abdominal wall and is located lateral and somewhat higher surface ring. 
As a result, hernias (inguinal) may occur here. 
It is closed by a connective tissue scar and can also be the site of formation hernia. The umbilical vein and two umbilical arteries pass through the umbilical ring in the fetus. The retracted fold of skin in the region of the umbilical ring is called the navel (umbilicus). 
