A flat four-sided muscle situated beneath the skin in the inner aspect of the thigh, which it wholly covers.

Origin. - From the under surface of the pelvis along the side of the ischio-pubic symphysis, where its fibres interlace with those of its fellow on the opposite side.

Insertion. - Into the internal straight ligament of the patella and the internal face of the tibia.

Action. - To adduct the leg and brace up the fibrous investment of the leg (tibial aponeurosis).

This muscle is attached to the sartorius in front.