Pectineus is a flat square muscle arising from the pectineal line between the iliopubic ramus and pubic tubercle and inserts into the lesser trochanter and linea aspera on the posterior surface of the femur.
It forms the medial part of the floor of the femoral triangle with iliacus and psoas major forming the lateral floor.
Anatomically it is located in the medial compartment of the thigh and adducts the thigh, however, since it both flexes the hip joint and is mainly supplied by the femoral nerve it
may be considered as part of the anterior compartment. Occasionally some of the fibres are innervated by the obturator nerve.