Adductor longus muscle

Origin and Insertion

The adductor longus, a muscle of the medial compartment of the thigh, is triangular in shape and forms in the floor of the femoral triangle and adductor canal.

The muscle originates from the anterior surface of the body of the pubis, inferior to pubic crest and lateral to the pubic symphysis. It inserts onto the middle third of the medial lip of the linea aspera. This insertion point is between the insertion of the adductor magnus and the origin of vastus medialis muscle, and inferior to the adductor brevis insertion.

Relations

The adductor longus muscle lies in front of the adductor magnus, adductor brevis muscle, the anterior branch of the obturator nerve, and deep femoral vessels. The pectineus muscle is lateral to it while gracilis lies medially. Anterior relations to its upper part are the spermatic cord and fascia lata, while the femoral artery and vein are present anterior to it in the lower part near its attachment.

Innervation

The adductor longus is supplied by the anterior division of the obturator nerve. All three adductors (except the hamstring part of the adductor magnus) and gracilis are supplied by the obturator nerve (anterior divisions of the anterior rami of spinal nerves L2-L4).

The obturator nerve is a branch of the lumbar plexus, and descends medial to the psoas major muscle in order to enter the pelvis. It runs behind the common iliac vessels, and lateral to the internal iliac artery and ureter. Next, it runs in the lateral wall of the pelvis, and will reach the superior part of the obturator foramen. It passes through the foramen and emerges into the obturator canal, and divides into an anterior and posterior branch. These branches are separated by obturator externus and adductor brevis.

The posterior branch pierces and supplies obturator externus, and descends in the medial compartment to supply adductor brevis and adductor magnus. The nerve also supplies sensation to the upper medial thigh. The anterior branch runs in front of obturator externus, and runs posterior to adductor longus (which it supplies) and pectineus (supplied by the femoral nerve).

As the nerve passes the hip, it also gives an articular branch to the joint. It supplies adductor longus, adductor brevis and gracilis.

Blood supply

The blood supply to adductor longus comes from two arteries, deep femoral artery (a branch of the femoral artery) and obturator artery (a branch of the internal iliac artery).

The proximal part of the muscle is supplied by the medial circumflex artery (branch of the deep femoral artery). The deep femoral vein receives tributaries that correspond to the branches of the artery.

Function

The main action of the adductor group of muscles is to adduct the thigh at the hip joint. The adductor longus muscle also participates in external/lateral rotation and flexion of the thigh. 

The adductors help to stabilize the stance while standing, and also have an important role in balancing the body on the lower limb during walking.

Now that you've come this far, take the last step and test your knowledge on the adductor longus and other muscles of the hip and thigh by taking the quiz below!