abdominal wall

(noun)

A layer of muscle and fascia which protects and encloses the abdominal cavity, allowing for its compression as well as torso movement.

Related Terms

Examples of abdominal wall in the following topics:

  • Anterior Muscles

    • The skeletal muscles of the abdomen form part of the abdominal wall, which holds and protects the gastrointestinal system.
    • Five muscles form the abdominal wall, divided into vertical and flat groups.
    • The fibers run in different directions and cross each other, strengthening the abdominal wall.
    • Its fibers run perpendicular to the external oblique, improving the strength of the abdominal wall.
    • The intercostals are muscles between the ribs that form the chest cavity wall.

  • Intercostal Nerves

    • The intercostal nerves are distributed chiefly to the thoracic pleura and abdominal peritoneum and differ from the anterior divisions of the other spinal nerves in that each pursues an independent course without plexus formation.
    • These are limited in their distribution to the parietes (wall) of the thorax.
    • The anterior divisions of the seventh, eighth, ninth, tenth, and eleventh thoracic intercostal nerves are continued anteriorly from the intercostal spaces into the abdominal wall; hence they are named thoraco-abdominal nerves (or thoracicoabdominal intercostal nerves).
    • The twelfth (subcostal) thoracic is distributed to the abdominal wall and groin.
    • This explains why damage to the internal wall of the thoracic cavity can be felt as a sharp pain localized in the injured region.

  • The Peritoneum

    • The peritoneum, the serous membrane that forms the lining of the abdominal cavity, covers most of the intra-abdominal organs.
    • It covers most of the intra-abdominal, or coelomic, organs.
    • The abdominal cavity is the open space surrounded by the vertebrae, abdominal muscles, diaphragm, and pelvic floor.
    • The outer layer, called the parietal peritoneum, is attached to the abdominal wall.
    • Sagittal section through posterior abdominal wall, showing the kidney residing outside the peritoneum.

  • Location and External Anatomy of the Kidneys

    • The kidneys are located at the rear wall of the abdominal cavity and they are protected by the ribcage.
    • The asymmetry within the abdominal cavity caused by the liver typically results in the right kidney being slightly lower than the left, and left kidney being located slightly more medial than the right.
    • The kidneys are located at the rear wall of the abdominal cavity just above the waistline and are protected by the ribcage.
    • They are considered retroperitoneal, which means that they lie behind the peritoneum, the membrane lining of the abdominal cavity.

  • Abdominal Aorta

    • The abdominal aorta is the largest artery in the abdominal cavity and supplies blood to most of the abdominal organs.
    • The abdominal aorta is the largest artery in the abdominal cavity.
    • It travels down the posterior wall of the abdomen, anterior to the vertebral column, following the curvature of the lumbar vertebrae.
    • The abdominal aorta runs parallel to the inferior vena cava, which is located just to the right of the abdominal aorta.
    • The abdominal aorta supplies blood to much of the abdominal cavity through numerous branches becoming smaller in diameter as it descends.

  • Defecation Reflex

    • As additional fecal material enters the rectum, the rectal walls expand.
    • A sufficient increase in fecal material in the rectum causes stretch receptors from the nervous system, located in the rectal walls, to trigger the contraction of rectal muscles, relaxation of the internal anal sphincter, and an initial contraction of the skeletal muscle of the external sphincter .
    • The abdominal muscles contract (straining), causing the intra-abdominal pressure to increase.
    • The perineal wall is lowered, causing the anorectal angle to decrease from 90 degrees to less than 15 degrees (almost straight), and the external anal sphincter relaxes.

  • Peritonitis

    • Peritonitis is an inflammation of the peritoneum , the thin tissue that lines the inner wall of the abdomen and covers most of the abdominal organs.
    • The main manifestations of peritonitis are acute abdominal pain, abdominal tenderness, and abdominal guarding, which are exacerbated by moving the peritoneum by coughing, flexing one's hips, or eliciting the Blumberg sign.
    • Diffuse abdominal rigidity ("washboard abdomen") is often present, especially in generalized peritonitis.
    • It can result from abdominal trauma and occurs if the large bowel is perforated during surgery.
    • Peritonitis is an inflammation of the peritoneum often causing abdominal pain and tenderness.

  • Inguinal Hernia

    • An inguinal hernia is a protrusion of abdominal-cavity contents through the inguinal canal.
    • An inguinal hernia is a protrusion of abdominal-cavity contents through the inguinal canal .
    • Direct inguinal hernias occur medial to the inferior epigastric vessels when abdominal contents herniate through a weak spot in the fascia of the posterior wall of the inguinal canal, which is formed by the transversalis fascia.
    • As a result, the possibility for hernias through the inguinal canal in males is much greater because they have a larger opening and therefore a much weaker wall for the intestines to protrude through.
    • Although several mechanisms such as strength of the posterior wall of the inguinal canal and shutter mechanisms compensating for raised intra-abdominal pressure prevent hernia formation in normal individuals, the exact importance of each factor is still under debate.

  • Aging and the Respiratory System

    • When requirements increase, the abdominal muscles resist expansion.
    • Increased abdominal pressure then tilts the diaphragm and ribcage upwards, increasing volume and air entry.
    • Expiration follows relaxation of diaphragm and abdominal muscles, but can be increased by the downward action of abdominal muscles on the rib cage.
    • This forced expiration increases pressure across walls of airways, and may lead to narrowing or even perhaps to wheezing.
    • In humans, conscious change often modifies autonomous reaction to need, a pattern that can vary due to things like fear or anxiety, loss of lung elasticity (due to aging), pulmonary diseases such as emphysema , or abdominal expansion from obesity.

  • Body Cavity Membranes

    • The mesothelium is a membrane that forms the lining of several body cavities: the pleura (thoracic cavity), peritoneum (abdominal cavity including the mesentery) and pericardium (heart sac).
    • Mesothelium that covers the internal organs is called visceral mesothelium, while the layer that covers the body walls is called the parietal mesothelium.
    • The peritoneum is the serous membrane that forms the lining of the abdominal cavity or the coelom—it covers most of the intra-abdominal (or coelomic) organs—in amniotes and some invertebrates (annelids, for instance).
    • The peritoneum both supports the abdominal organs and serves as a conduit for their blood and lymph vessels and nerves.The abdominal cavity (the space bounded by the vertebrae, abdominal muscles, diaphragm and pelvic floor) should not be confused with the intraperitoneal space (located within the abdominal cavity, but wrapped in peritoneum).
    • The structures within the intraperitoneal space are called "intraperitoneal" (e.g. the stomach), the structures in the abdominal cavity that are located behind the intraperitoneal space are called "retroperitoneal" (e.g. the kidneys), and those structures below the intraperitoneal space are called "subperitoneal" or "infraperitoneal" (e.g. the bladder).