The pectineus (also pectineus muscle, latin: musculus pectineus) is flat, quadrangular muscle situated in the medial region of the thigh.
The pectineus originates from the pectineal line of the pubic bone. Fibers of the pectineus muscle pass downward and in posterolateral direction and insert onto the pectineal line of the femur.
The main function of the pectineus is flexion of the hip. Other functions of the pectineus muscle are adduction and external rotation of the hip.