Pectineus Muscle

Description

Arising from the superior ramus of the pubis, the pectineus forms a flat, quadrangular muscle on the anteromedial thigh, lying inferior to the inguinal ligament and just anterior to the hip joint capsule. Its fibers pass inferolaterally to insert along the pectineal line of the femur, placing the muscle medial to iliopsoas and lateral to adductor longus at the proximal thigh. Clear margins separate it from the adductor compartment posteriorly, while the femoral triangle structures sit superficial and slightly lateral. Small but telling. Functionally, pectineus sits at the crossroads between hip flexion and adduction, and this morphology helps explain why it is sometimes described as a transitional muscle between the anterior and medial thigh compartments. The view is also useful for teaching the floor of the femoral triangle, where pectineus and iliopsoas form the muscular bed beneath the femoral vessels and nerve, and where a femoral hernia can track through the femoral canal medial to the vein. Its innervation is variable (often femoral nerve, sometimes obturator), a practical point when correlating groin pain, postoperative weakness, or selective denervation patterns. Use this figure in gross anatomy and musculoskeletal medicine courses to orient learners to proximal medial thigh landmarks, or in surgical and sports medicine publications discussing adductor-related groin pain, femoral triangle approaches, and hip flexor strain differentials. It also supports radiology teaching when correlating the pectineal line insertion and adjacent adductor planes on axial CT or MRI at the level of the lesser trochanter. Anatomical accuracy verified by SciePro's Medical Advisory Board.