Abdominal muscles

Rectus abdominis

This is your stomach muscle. It pulls in your stomach, and flexes the trunk to make bending forward possible (spine flexion).

Obliques

These are found at the side of your stomach. They twist the trunk (spine rotation). The internal oblique fibres fan upward and forward and run at right angles to those of the external oblique, which it underlies. The external obliques are the largest and most superficial of the three lateral (side) muscles. Its fibres run downward and medially.

Transversus abdominis

This is the deepest muscle of the abdominal wall and its fibres run horizontally. It is important for compressing the abdomen.