The pectineus muscle (, from the Latin word ''pecten'', meaning comb) is a flat, quadrangular

muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...

, situated at the

anterior Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

(front) part of the upper and medial (inner) aspect of the

thigh In anatomy, the thigh is the area between the hip (pelvis) and the knee. Anatomically, it is part of the lower limb. The single bone in the thigh is called the femur. This bone is very thick and strong (due to the high proportion of bone tissu ...

. 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 (when the function is emphasized) or the anterior compartment of thigh (when the nerve is emphasized).

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 The pubic tubercle is a prominent tubercle on the superior ramus of the pubis bone of the pelvis. Structure The pubic tubercle is a prominent forward-projecting tubercle on the upper border of the medial portion of the superior ramus of th ...

, 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 In human anatomy, the lesser trochanter is a conical, posteromedial, bony projection from the shaft of the femur. It serves as the principal insertion site of the iliopsoas muscle. Structure The lesser trochanter is a conical posteromedial p ...

to the

linea aspera The linea aspera () is a ridge of roughened surface on the posterior surface of the shaft of the femur. It is the site of attachments of muscles and the intermuscular septum. Its margins diverge above and below. The linea aspera is a prominent ...

Relations

The pectineus is in relation by its anterior surface with the pubic portion of the

fascia lata The fascia lata is the deep fascia of the thigh. It encloses the thigh muscles and forms the outer limit of the fascial compartments of thigh, which are internally separated by the medial intermuscular septum and the lateral intermuscular sept ...

, which separates it from the

femoral artery The femoral artery is a large artery in the thigh and the main arterial supply to the thigh and leg. The femoral artery gives off the deep femoral artery and descends along the anteromedial part of the thigh in the femoral triangle. It enters ...

and

vein Veins () are blood vessels in the circulatory system of humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are those of the pulmonary and feta ...

and internal saphenous vein, and lower down with the

profunda femoris artery The deep femoral artery also known as the deep artery of the thigh, or profunda femoris artery, is a large branch of the femoral artery. It travels more deeply ("profoundly") than the rest of the femoral artery. It gives rise to the lateral ci ...

. By its posterior surface with the capsule of the hip joint, and with the

obturator externus The external obturator muscle or obturator externus muscle (; OE) is a flat, triangular muscle, which covers the outer surface of the anterior wall of the pelvis. It is sometimes considered part of the medial compartment of thigh, and sometime ...

and

adductor brevis The adductor brevis is a muscle in the thigh situated immediately deep to the pectineus and adductor longus. It belongs to the adductor muscle group. The main function of the adductor brevis is to pull the thigh medially. The adductor brevi ...

, the obturator artery and

being interposed. By its external border with the

psoas major The psoas major ( or ; from ) is a long fusiform muscle located in the lateral lumbar region between the vertebral column and the brim of the lesser pelvis. It joins the iliacus muscle to form the iliopsoas. In other animals, this muscle is e ...

, the

resting upon the line of interval. By its internal border with the outer edge of the

adductor longus In the human body, the adductor longus is a skeletal muscle located in the thigh. One of the adductor muscles of the hip, its main function is to Adduction, adduct the thigh and it is innervated by the obturator nerve. It forms the medial wall ...

Obturator foramen The obturator foramen is the large, Bilateral symmetry, bilaterally paired opening of the bony pelvis. It is formed by the pubis and ischium. It is mostly closed by the obturator membrane except for a small opening, the obturator canal, through wh ...

is situated directly behind this muscle, which forms one of its coverings. It forms part of the floor of the

femoral triangle The femoral triangle (or Scarpa's triangle) is an anatomical region of the upper third of the thigh. It is a subfascial space which appears as a triangular depression below the inguinal ligament when the thigh is flexed, abducted and laterally r ...

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 The femoral nerve is a nerve in the thigh that supplies skin on the upper thigh and inner leg, and the muscles that extend the knee. It is the largest branch of the lumbar plexus. Structure The femoral nerve is the major nerve supplying the ant ...

(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 Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relativ ...

. Secondarily, it also internally rotates the thigh.

Additional images

File:Gray235.png, Right hip bone. External surface. File:Gray344.png, Structures surrounding right hip-joint. File:Gray430.png, Muscles of the iliac and anterior femoral regions. File:Gray433.png, Deep muscles of the medial femoral region. File:Gray549.png, The left femoral triangle. File:Gray823.png, The lumbar plexus and its branches. File:Slide3GGGGG.JPG, Pectineus muscle File:Slide2LLLL.JPG, Pectineus muscle File:Slide13LLLL.JPG, Pectineus muscle File:Slide4NNNNN.JPG, Pectineus muscle File:Slide1WWWW.JPG, Pectineus muscle File:Slide1BOUA.JPG, Muscles of thigh. Anterior views File:Slide1DEEA.JPG, Muscles of thigh. Anterior views.

References

Notes

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

External links

* - "Muscles of the anterior (extensor) compartment of the thigh." * - "Deep muscles of the anterior thigh." * {{Authority control Hip adductors Hip medial rotators Hip flexors Thigh muscles Medial compartment of thigh