Gracilis muscle

At a glance

English

Gracilis muscle

Latin (TA2)

Musculus gracilis

System

Muscle

Region

Lower limb

Side

Paired, left and right

About the gracilis muscle

Gracilis, whose name means slender in Latin, lies closer to the skin than any other muscle of the inner thigh. Flat and thin, it is wide at the top and narrows to a cord below. It is also the only member of the adductor group that crosses the knee as well as the hip.

Its origin is a thin aponeurosis on the lower half of the body of the pubis and the inferior pubic ramus near the symphysis. Its fibres run straight down the inner thigh to a rounded tendon, which passes behind the medial femoral condyle, curves round the medial tibial condyle and flattens out to attach on the upper medial surface of the tibia, just under its condyle. There it lies between sartorius in front and semitendinosus behind, the three forming the pes anserinus; a bursa separates them from the tibial collateral ligament of the knee. A few fibres carry on into the crural fascia.

Superficially it is covered by the fascia lata, with sartorius and the saphenous nerve below and the great saphenous vein crossing over it. Deeply it lies on the three adductors. Gracilis adducts the thigh, helps flex the hip, flexes the knee and, when the knee is bent, rotates the leg medially. With sartorius and semitendinosus it also helps brace the inner side of the knee.

Gracilis is a favourite donor muscle in reconstructive surgery, because the body manages well without it and it has a dominant blood supply: one main artery from the medial circumflex femoral or deep femoral artery enters about a hand's breadth below the pubis, with the obturator nerve branch entering close by. It can be moved with that pedicle intact or transplanted with its nerve and vessels to cover wounds of the limbs, or to restore movement, for example to reanimate a paralysed face or to replace lost forearm muscle function. Its tendon is also commonly taken to rebuild torn knee ligaments.

Attachments, action and supply

Origin

Lower half of the body of the pubis and the inferior pubic ramus, by a thin aponeurosis.

Insertion

Upper medial surface of the tibia, below the medial condyle, as part of the pes anserinus.

Action

Adducts the thigh, helps flex the hip, flexes the knee and medially rotates the flexed leg.

Nerve supply

Obturator nerve, anterior division (L2, L3).

Blood supply

Branch of the medial circumflex femoral or deep femoral artery as the main pedicle, with smaller branches from the obturator and femoral arteries.