16th February 2024

Abdominal wall

The abdominal wall can be divided into the anterior, posterior, and inguinal canals. 

Anterior abdominal wall

The abdominal wall is made up of 4 muscles: external and internal obliques, transverses abdominis and rectus abdominis. The aponeurosis of the former three muscles comes together to form a rectus sheath. The anterior abdominal wall is supplied by the anterior rami of the lower six thoracic and the first lumbar nerves. Some paraumbilical veins connect through the ligamentum teres to the portal vein, which is one of the sites of portosystemic anastomosis.

Posterior abdominal wall

The posterior abdominal walls are made up of the lumbar vertebrae with their intervertebral discs, twelfth ribs, upper part of the iliac bones, psoas major, quadratus lumborum, iliacus and origin of transversus abdominis.

Inguinal canal

There are two oblique passages, one on each side, in the lower abdomen, known as the inguinal canal. These canals transmit the spermatic cord in males and the round ligament in females, along with the ilioinguinal nerve and genital branch of the genitofemoral nerve in both sexes. 

The inguinal canal is bordered by the aponeurosis of the external oblique and internal oblique muscle anteriorly; transversal fascia posteriorly; transversal fascia, internal oblique and transversus abdominis superiorly; and the inguinal ligament and lacunar ligament inferiorly.