pectineus

The pectineus is a flat, quadrangular muscle of the anterior thigh. It lies in the upper medial region of the thigh and contributes to the floor of the femoral triangle, where it is closely associated with the iliopsoas.

Origin and insertion: The muscle originates from the superior ramus of the pubis, and in some individuals also from surrounding fascia. It inserts along the pectineal line of the femur, just below the lesser trochanter, blending with the proximal lineae aspera.

Nerve supply: The pectineus is usually innervated by the femoral nerve (L2–L4). In some people, a contribution from the obturator nerve or accessory obturator nerve may be present.

Blood supply: Its vascular supply primarily comes from branches of the medial femoral circumflex artery, with additional contributions from branches of the profunda femoris (deep artery of the thigh) and sometimes the obturator artery.

Actions: The muscle flexes and adducts the thigh at the hip joint and may assist with medial rotation. It also helps stabilize the pelvis during gait.

Relationships: The pectineus lies anterior and medial in the thigh, deep to the sartorius, and forms part of the floor of the femoral triangle as it passes toward its insertion.

Clinical significance: Pectineus involvement can occur in groin or hip injuries and strains, particularly in athletes. Variations in innervation and anatomy are described, and the muscle may be absent or fused with adjacent structures in some individuals.