Hip Muscles

Gluteus Maximus

Origin (BDC):
Outer slope of dorsal segment of iliac crest, posterior gluteal line, lower sacrum/coccyx, sacrotuberous ligament.

Insertion (BDC):
Iliotibial tract (deep fascia of thigh) & gluteal tuberosity of the femur.

Nerve Supply:
Inferior gluteal nerve (L5, S1, S2).

Blood Supply:
Superior and inferior gluteal arteries.

Action:
Chief extensor of the thigh at the hip joint; lateral rotation.

Biomechanics (Norkin):
Generates greatest tension when hip is in flexion (e.g., stair climbing). Strongly active to control forward trunk momentum during the stance phase of gait.

Iliopsoas

Origin (BDC):
Psoas: Transverse processes and bodies of T12-L5.
Iliacus: Upper 2/3 of iliac fossa.

Insertion (BDC):
Lesser trochanter of the femur.

Nerve Supply:
Lumbar plexus (L1-L3) for Psoas; Femoral nerve (L2-L4) for Iliacus.

Blood Supply:
Iliolumbar and circumflex iliac arteries.

Action:
Chief flexor of the hip joint. Flexes the trunk when legs are fixed.

Biomechanics (Norkin):
Primary hip flexor utilized during the swing phase of gait. Acts as a dynamic stabilizer of the lumbar spine. Tightness creates excessive anterior pelvic tilt.

Gluteus Medius

Origin (BDC):
Outer surface of ilium between the anterior and posterior gluteal lines.

Insertion (BDC):
Lateral surface of the greater trochanter of the femur.

Nerve Supply:
Superior gluteal nerve (L4, L5, S1).

Blood Supply:
Superior gluteal artery.

Action:
Powerful abductor of the thigh. Anterior fibers medially rotate; posterior fibers laterally rotate.

Biomechanics (Norkin):
Crucial pelvic stabilizer during unilateral stance (prevents Trendelenburg sign). Operates with a mechanical disadvantage due to short lever arm, requiring high force.