Pectineus muscle

Pectineus

The pectineus and nearby muscles

Structures passing behind the inguinal ligament (pectineus visible at bottom right.)
Details
Origin Pectineal line of the pubic bone
Insertion Pectineal line of the femur
Artery Obturator artery
Nerve Femoral nerve, sometimes obturator nerve
Actions Thigh - flexion, adduction
Identifiers
Latin Musculus pectineus
TA A04.7.02.025
FMA 22440

Anatomical terms of muscle

The pectineus muscle (from the Latin word pecten, meaning comb[1]) 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 does adduct and externally rotate the thigh but its primary function is hip flexion.

It can be classified in the medial compartment of thigh[2] (when the function is emphasized) or the anterior compartment of thigh (when the nerve is emphasized).[3]

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 vein and internal saphenous vein, and lower down with the profunda artery.

By its posterior surface with the capsule of the hip joint, and with the obturator externus and adductor brevis, the obturator artery and 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 hernia is situated directly behind this muscle, which forms one of its coverings.[4]

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.[5]

Function

It is one of the muscles primarily responsible for hip flexion. It also adducts the thigh.

Additional images

See also

This article uses anatomical terminology; for an overview, see Anatomical terminology.

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

  1. ↑ Mosby's Medical, Nursing & Allied Health Dictionary, Fourth Edition, Mosby-Year Book Inc., 1994, p. 1177
  2. ↑ Ellis, Harold; Susan Standring; Gray, Henry David (2005). Gray's anatomy: the anatomical basis of clinical practice. St. Louis, Mo: Elsevier Churchill Livingstone. p. 518. ISBN 0-443-07168-3.
  3. ↑ medialthigh at The Anatomy Lesson by Wesley Norman (Georgetown University)
  4. ↑ Wilson, Erasmus (1851). The anatomist's vade mecum: a system of human anatomy. p. 260.
  5. ↑ 5

Woodburne, Russell. "The Accessory Obturator Nerve and the Innervation of the Pectineus Muscle". Michigan Library Med School: 367–369.  http://deepblue.lib.umich.edu/bitstream/handle/2027.42/49789/1091360303_ftp.pdf?sequence=1

Saladin, Kenneth S. Anatomy & Physiology: The Unity of Form and Function. New York, NY: McGraw-Hill, 2007. pg.493. Print.

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