Leg Muscles

Muscle Anatomy Overview

1. Iliopsoas

  • Origin: Iliacus part - iliac fossa; Psoas major part - transverse processes, bodies, and intervertebral discs of T12-L5.

  • Insertion: Lesser trochanter of the femur.

  • Action: Hip flexion.

2. Rectus Femoris

  • Origin: Anterior inferior iliac spine (AIIS) and ilium above the acetabulum.

  • Insertion: Tibial tuberosity via the patellar ligament.

  • Action: Knee extension and hip flexion.

3. Sartorius

  • Origin: Anterior superior iliac spine (ASIS).

  • Insertion: Medial aspect of the tibia (part of the pes anserinus).

  • Action: Flexes, abducts, and laterally rotates the hip; also flexes the knee.

4. Tensor Fasciae Latae (TFL)

  • Origin: Anterior aspect of the iliac crest and ASIS.

  • Insertion: Iliotibial tract, which attaches to the lateral condyle of the tibia.

  • Action: Abducts, flexes, and internally rotates the hip.

5. Gluteus Maximus

  • Origin: Ilium, sacrum, and coccyx.

  • Insertion: Gluteal tuberosity of the femur and iliotibial tract.

  • Action: Extends and externally rotates the hip.

6. Biceps Femoris

  • Origin: Long head - ischial tuberosity; Short head - linea aspera of the femur.

  • Insertion: Head of the fibula and lateral condyle of the tibia.

  • Action: Knee flexion and hip extension (long head).

7. Gluteus Medius

  • Origin: Outer surface of the ilium.

  • Insertion: Greater trochanter of the femur.

  • Action: Abducts and medially rotates the hip.

8. Adductor Longus

  • Origin: Body of the pubis.

  • Insertion: Middle third of the linea aspera of the femur.

  • Action: Adducts and flexes the hip.

9. Gastrocnemius

  • Origin: Medial and lateral condyles of the femur.

  • Insertion: Calcaneus via the Achilles tendon.

  • Action: Plantar flexes the ankle and flexes the knee.

10. Soleus

  • Origin: Proximal tibia and fibula, and interosseous membrane.

  • Insertion: Calcaneus via the Achilles tendon.

  • Action: Plantar flexes the ankle.

11. Tibialis Anterior

  • Origin: Lateral condyle and upper two-thirds of the lateral surface of the tibia.

  • Insertion: Medial cuneiform and first metatarsal.

  • Action: Dorsiflexes and inverts the foot.