Corpus: Abdominal wall
1. Definition
The abdominal wall forms the circular closure of the abdominal cavity.
2. Layers
The abdominal wall is anatomically divided into three main regions: ventral (anterior), lateral (side), and dorsal (posterior). It consists of distinct tissue layers grouped into three broad categories:
- Superficial layer
- Skin (cutis)
- Subcutaneous layer (subcutis)
- Superficial abdominal fascia
- Middle layer
- Aponeurosis of the obliquus externus muscle
- Obliquus internus muscle and transversus abdominis muscle
- Rectus abdominis muscle and rectus sheath
- Transversalis fascia
- Deep layer
- Subserosal connective tissue
- Parietal peritoneum
The quadratus lumborum muscle contributes to the structure of the dorsal abdominal wall.
Notably, the positional relationship of the rectus abdominis muscle to surrounding structures differs above and below the arcuate line.
3. Properties
The ventral and lateral sections of the abdominal wall lack bony support, making the muscular and tendinous middle layer the primary load-bearing structure. The abdominal wall has several important functions, including its role in expiration, trunk movement, and the protection of abdominal organs.
Weak points in the abdominal wall may give way and lead to herniation. Hernias, characterized by the protrusion of a hernia sac through the abdominal wall, are among the most common surgical conditions.