Gracilis Anatomy

Gracilis Muscle

Origin: Lower half of the body of the pubis, the inferior pubic ramus, and the adjoining part of the ischial ramus.
Insertion: Upper part of the medial flare of the tibia, just below the medial condyle, proximal and slightly anterior to the attachment of semitendinosus, and posterior and somewhat inferior to the attachment of sartorius.
Actions: Assists with flexion and adduction of the thigh
Innervation: Anterior division of the femoral nerve (L2. L3)
Blood Supply: Obturator artery from the internal iliac artery

Primary Actions of the Gracilis

1. Because of its lack of mechanical advantage, the gracilis is not capable of isolated movements. It does not have a primary action.

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Secondary Actions of the Gracilis

1. Assists with flexion of the knee
Agonists:

  • Biceps femoris
  • Semitendinosus
  • Semimembranosus

Antagonists:

  • Vastus lateralis
  • Vastus medialis
  • Vastus intermedius
  • Rectus femoris

Sartoriuspopliteusgastrocnemius, and plantaris also assist with flexion of the knee.

2. Assists with internal rotation of the knee when the knee is flexed
Agonists:

  • Popliteus
  • Semitendinosus
  • Semimembranosus

Antagonists:

  • Biceps femoris

The Sartorius also assists with internal rotation of the knee when the knee is flexed.


3. Assists with adduction of the thigh at the hip

Agonists:

  • Adductor longus
  • Adductor brevis
  • Adductor magnus (anterior part)

Antagonists:

  • Gluteus maximus (upper fibers)
  • Gluteus medius
  • Gluteus minimus

Pectineus also assists with adduction of the thigh at the hip.