The pectineus muscle is a flat, quadrangular muscle, situated at the anterior (front) part of the upper and medial (inner) aspect of the thigh. The pectineus muscle is the most anterior adductor of the hip. The muscle's primary action is hip flexion; it also produces adduction and internal rotation of the hip.

In anatomy, the thigh is the area between the hip (pelvis) and the knee. Anatomically, it is part of the lower limb.