The abdominal wall consists of three layers composed of different types of tissue and delimits the abdominal cavity with the abdominal organs. Damage to the tissues of the abdominal wall or weakening of the muscles that belong to it will result in various symptoms.
What characterizes the abdominal wall?
The abdominal wall surrounds and delimits the abdominal cavity. It connects the chest and pelvis. The abdominal wall is divided into three parts, the ventral (front), lateral (side) and dorsal (back) parts. The term abdominal wall is usually used to refer only to the ventral as well as the lateral sections of the abdominal wall. The abdominal wall is composed of three layers with different types of tissue. The ventral and lateral sections of the abdominal wall are devoid of bone, and here the middle layer of muscles and tendons carries most of the load. The organs located in the abdominal cavity and the fatty tissue covered by the peritoneum exert pressure on the abdominal wall, which is counteracted by the abdominal muscles.
Anatomy and structure
The superficial layer of the abdominal wall consists of the so-called cutis, which is the epidermis and dermis. Below this is the subcutis, a skin layer of connective and fatty tissue, and the fascia abdominalis, the superficial body fascia. The connective tissue is permeated by blood vessels and nerves. The middle layer consists of various abdominal muscles, the fascia transversalis (the internal abdominal fascia), and the rectus sheath. The abdominal muscles include the obliquus externus abdominis muscle (external abdominal muscle], the obliquus internus abdominis muscle (internal oblique abdominal muscle), the transversus abdominis muscle (transverse abdominal muscle), and the rectus abdominis muscle (straight abdominal muscle]. The rectus sheath is a canal formed by tendon plates, which contains muscles, nerves, and vessels. The third or deep layer of the abdominal wall contains connective tissue and what is called the peritoneum or peritoneum, which lines the abdominal cavity. The peritoneum attaches to the internal abdominal fascia with the parietal peritoneum, which is the outer leaflet of the peritoneum. The visceral peritoneum covers the abdominal organs.
Function and Tasks
The abdominal wall has multiple functions. For example, it serves to protect the abdominal organs. These include the liver, gall bladder, stomach, intestines, pancreas and spleen. In the subcutis, the so-called subcutaneous tissue, fat can be stored as an energy store for the body. The storage of fat also serves as protection against the loss of heat. The middle, muscular layer of the abdominal wall provides forward mobility of the trunk and allows the upper body to rotate. It also stabilizes the abdominal wall. As respiratory support muscles, the musculature of the abdominal wall supports exhalation and the interaction between the heartbeat and breathing. They also support the spine and back muscles. With the help of the so-called abdominal press, in which pressure is exerted on the abdominal cavity by tensing the abdominal muscles, defecation can be supported in interaction with the pelvic floor muscles and the diaphragm. Similarly, the muscles of the abdominal wall can help empty the bladder in cases of bladder voiding dysfunction. The abdominal press can also enhance the effect of labor during the birth process. The peritoneum, which lies in folds in the deep layer of the abdominal wall, envelops the abdominal organs and can release and absorb the so-called peritoneal fluid, a secretion that acts as a kind of lubricant. This allows the organs located in the abdominal cavity to move against each other more easily. This is necessary, for example, during food intake by a filled stomach, during pregnancy, during movements and during breathing. At the same time, it keeps the abdominal organs in their intended position and protects them. The peritoneum is permeated by blood and lymph vessels, as well as nerves, and thereby supplies the organs.
Diseases and disorders
Disease or damage to the abdominal wall can lead to a variety of complaints. These include pulling pain in the abdominal area, which is often more severe when moving, coughing or lifting heavy objects than at rest. For example, weaknesses or tears in the layers of the abdominal wall can lead to what is known as a hernia, or rupture, in which viscera can push outward, form protrusions, and be visible through a lump at the site of the rupture.There are weak points, for example, in the umbilical and inguinal regions, where an umbilical or inguinal hernia can occur, which are not bone fractures but hernias. Hernias are among the most common surgical conditions. A hernia can also result from a malformation of the abdominal wall in embryonic age, where gaps may already form in the tissue layers due to a lack of blood supply. Likewise, a hernia can result from a so-called postoperative laparoschisis. This refers to a cleft in the tissue layers that occurs after a surgical procedure. Inflammation of the abdominal wall can lead to a reflex defensive tension of the abdominal muscles. If the peritoneum is irritated, this can lead to nausea and vomiting or dizziness. In a condition called ascites, increased fluid accumulates in the peritoneum and the abdomen swells. In appendicitis, inflammation of the peritoneum often occurs as a concomitant disease and is associated with severe pain. If the abdominal muscles of the middle layer of the abdominal wall are too weakly developed, back pain may occur. The lumbar spine bends forward, a hollow back develops and, in addition to tension in the back muscles, can lead to permanent damage to the intervertebral discs. Another problem related to the abdominal wall can be tumor diseases such as lipomas or liposarcomas in the subcutis. In addition, in tumor diseases of the internal organs, metastases often form in the peritoneal area.
