AOII: Leg Muscles

Iliopsoas

Action: Flexes thigh and lumbar vertebrae

Origin: T12, L1–5, iliac fossa

Insertion: Lesser trochanter of femur

Innervation: Femoral nerve, spinal nerves L1–3

Sartorius

Action: Flexes and laterally rotates thigh, flexes leg
Origin: Anterior superior iliac spine
Insertion: Proximal, medial tibia
Innervation: Femoral nerve

Gracilis

Action: Adducts thigh, flexes leg
Origin: Pubis, near symphysis
Insertion: Proximal, medial tibia
Innervation: Obturator nerve

Pectineus

Action: Adducts thigh
Origin: Pubic crest
Insertion: Pectineal line of femur
Innervation: Femoral and obturator nerves

Adductor brevis

Action: Adducts, flexes, and laterally rotates thigh
Origin: Pubis
Insertion: Linea aspera at proximal portion of femur
Innervation: Obturator nerve

Adductor longus

Action: Adducts, flexes, and laterally rotates thigh
Origin: Pubis
Insertion: Linea aspera at middle portion of femur
Innervation: Obturator nerve

Adductor magnus

Action: Adducts, extends, and laterally rotates thigh
Origin: Pubis, ischium
Insertion: Linea aspera, adductor tubercle of distal femur
Innervation: Obturator and tibial nerves

Rectus femoris

Action: Flexes thigh, extends leg
Origin: Anterior inferior iliac spine
Insertion: Tibial tuberosity by the patellar ligament
Innervation: Femoral nerve

Vastus lateralis

Action: Extends leg
Origin: Greater trochanter of femur, linea aspera of femur
Insertion: Tibial tuberosity by the patellar ligament
Innervation: Femoral nerve

Vastus intermedius

Action: Extends leg
Origin: Proximal, anterior femur
Insertion: Tibial tuberosity by the patellar ligament
Innervation: Femoral nerve

Vastus medialis

Action: Extends leg
Origin: Linea aspera of femur, on medial side
Insertion: Tibial tuberosity by the patellar ligament
Innervation: Femoral nerve

Tensor fasciae latae

Action: Flexes, abducts, and medially rotates thigh
Origin: Anterior superior iliac spine
Insertion: Iliotibial band of fasciae latae to lateral condyle of tibia
Innervation: Superior gluteal nerve

Gluteus maximus

Action: Extends, abducts, and laterally rotates thigh; braces knee
Origin: Outer iliac blade, iliac crest, sacrum, coccyx
Insertion: Gluteal tuberosity of femur, iliotibial band of fasciae latae
Innervation: Inferior gluteal nerve

Gluteus medius

Action: Abducts and medially rotates thigh
Origin: Outer iliac blade
Insertion: Greater trochanter of femur
Innervation: Superior gluteal nerve

Gluteus minimus

Action: Abducts and medially rotates thigh
Origin: Outer iliac blade
Insertion: Greater trochanter of femur
Innervation: Superior gluteal nerve

Biceps femoris

Action: Extends thigh, flexes leg
Origin: Ischial tuberosity, linea aspera of femur
Insertion: Head of fibula, lateral condyle of tibia
Innervation: Tibial and fibular nerves

Semitendinosus

Action: Extends thigh, flexes leg
Origin: Ischial tuberosity
Insertion: Proximal, medial tibia
Innervation: Tibial nerve

Semimembranosus

Action: Extends thigh, flexes leg
Origin: Ischial tuberosity
Insertion: Medial condyle of tibia, collateral ligament
Innervation: Tibial nerve

Tibialis anterior

Action: Dorsiflexes and inverts foot
Origin: Tibia, interosseous membrane
Insertion: Metatarsal 1 and cuneiform 1
Innervation: Deep fibular nerve

Extensor digitorum longus

Action: Extends toes 2–5, dorsiflexes and everts foot
Origin: Lateral condyle of tibia, shaft of fibula
Insertion: Middle and distal phalanges of digits 2–5
Innervation: Deep fibular nerve

Extensor hallucis longus

Action: Extends hallux, dorsiflexes foot, inverts foot
Origin: Anterior shaft of fibula, interosseous membrane
Insertion: Distal phalanx of hallux (big toe)
Innervation: Deep fibular nerve

Fibularis longus

Action: Plantar flexes and everts foot
Origin: Head and shaft of fibula, lateral condyle of tibia
Insertion: Metatarsal 1, cuneiform 1
Innervation: Superficial fibular nerve

Fibularis brevis

Action: Plantar flexes and everts foot
Origin: Shaft of fibula
Insertion: Metatarsal 5
Innervation: Superficial fibular nerve

Fibularis tertius

Action: Dorsiflexes and everts foot
Origin: Fibula, interosseous membrane
Insertion: Dorsum of metatarsal 5
Innervation: Deep fibular nerve

Gastrocnemius

Action: Flexes leg, plantar flexes foot
Origin: Condyles of femur
Insertion: Calcaneus by the calcaneal tendon
Innervation: Tibial nerve

Soleus

Action: Plantar flexes foot
Origin: Posterior, proximal tibia; fibula
Insertion: Calcaneus by the calcaneal tendon
Innervation: Tibial nerve

Popliteus

Action: Flexes leg
Origin: Lateral condyle of femur
Insertion: Proximal tibia
Innervation: Tibial nerve

Tibialis posterior

Action: Plantar flexes and inverts foot
Origin: Interosseous membrane, tibia, fibula
Insertion: Metatarsals 2–5, navicular, cuneiforms, cuboid
Innervation: Tibial nerve

Flexor digitorum longus

Action: Flexes toes 2–5, plantar flexes and inverts foot
Origin: Posterior tibia
Insertion: Distal phalanges of digits 2–5
Innervation: Tibial nerve

Flexor hallucis longus

Action: Flexes hallux, plantar flexes and inverts foot
Origin: Midshaft of fibula
Insertion: Distal phalanx of hallux (big toe)
Innervation: Tibial ne