The pectineus muscle (, from the Latin word pecten, meaning comb)[Mosby's Medical, Nursing & Allied Health Dictionary, Fourth Edition, Mosby-Year Book Inc., 1994, p. 1177] 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 external rotation of the hip.
It can be classified in the medial compartment of thigh
Structure
The pectineus muscle arises from the pectineal line of the pubis and to a slight extent from the surface of bone in front of it, between the iliopectineal eminence and
pubic tubercle, and from the fascia covering the anterior surface of the muscle; the fibers pass downward, backward, and lateral, to be inserted into the pectineal line of the femur which leads from the lesser trochanter to the
linea aspera.
Relations
The pectineus is in relation by its anterior surface with the pubic portion of the
fascia lata, which separates it from the
femoral artery and
Femoral vein and internal saphenous vein, and lower down with the profunda femoris artery.
By its posterior surface with the capsule of the hip joint, and with the obturator externus and adductor brevis, the obturator artery and Obturator vein being interposed.
By its external border with the psoas major, the femoral artery resting upon the line of interval.
By its internal border with the outer edge of the adductor longus.
Obturator foramen is situated directly behind this muscle, which forms one of its coverings.
It forms part of the floor of the femoral triangle.
Innervation
The lumbar plexus is formed from the anterior rami of nerves L1 to L4 and some fibers from T12. With only five roots and two divisions, it is less complex than the brachial plexus and gives rise to a number of nerves including the femoral nerve and accessory obturator nerve. The pectineus muscle is considered a
composite muscle as the innervation is by the
femoral nerve (L2 and L3) and occasionally (20% of the population) a branch of the
obturator nerve called the accessory obturator nerve. When it is present, the accessory obturator nerve innervates a portion of the pectineus muscle, entering the muscle on its dorsomedial aspect. The greater nerve to the muscle is the femoral nerve. Unlike the obturator accessory nerve, the femoral nerve is always present and provides the sole innervation for the pectineus muscle in over 90% of cases. The muscle is also innervated by the accessory obturator nerve in the 8.7% of cases in which the nerve occurs.
Function
Its primary functions are contributing to
hip flexion and hip
adduction. Secondarily, it also internally rotates the thigh.
==Additional images==
See also
Notes
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Saladin, Kenneth S. Anatomy & Physiology: The Unity of Form and Function. New York, NY: McGraw-Hill, 2007. pg.493. Print.
External links
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- "Muscles of the anterior (extensor) compartment of the thigh."
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- "Deep muscles of the anterior thigh."
