1. The outer margins of the abdomen, extending from the osteocartilaginous thoracic cage to the pelvis: Although its major part is muscular, the abdominal wall consists of at least seven layers: the skiln, subcutaneous fat, deep fascia, abdominal muscles, transversalis fascia, extraperitoneal fat, and the parietal peritoneum.

2. The lining of the abdomen, consisting partly of bone but mostly of muscle: Several sets of muscles support and propel the torso or body, for example the abdominal wall muscles which help transfer force between the upper and lower body, and they also protect the delicate internal organs, and their most important function is to support the back.

The muscles of the torso extend in several directions and they help to maintain the posture and aid the spinal muscles when bending, twisting, and when doing other movements.