Part 3: Leg Muscles (+Feet)

Question 1

Tibialis Anterior

Answer 1

Origin: Lateral condyle and proximal half of tibia

Insertion: Medial cuneiform and first metatarsal bone

Action: Dorsiflexion of the ankle, inversion of the foot

Innervation: Deep peroneal nerve (L4-L5)

Blood Supply: Anterior tibial artery

Question 2

Extensor Hallucis Longus

Answer 2

Origin: Middle part of fibula

Insertion: Base of the distal phalanx of the great toe (hallux)

Action: Extension of the big toe, dorsiflexion of the ankle

Innervation: Deep peroneal nerve (L5-S1)

Blood Supply: Anterior tibial artery

Question 3

Extensor Digitorum Longus

Answer 3

Origin: Lateral condyle of tibia, proximal fibula, and interosseous membrane

Insertion: Middle and distal phalanges of lateral four toes

Action: Extension of the lateral four toes, dorsiflexion of the ankle

Innervation: Deep peroneal nerve (L5-S1)

Blood Supply: Anterior tibial artery

Question 4

Gastrocnemius:

Answer 4

Origin: Medial and lateral condyles of femur

Insertion: Calcaneus via Achilles tendon

Action: Plantar flexion of the ankle, flexion of the knee (when the foot is dorsiflexed)

Innervation: Tibial nerve (S1-S2)

Blood Supply: Sural arteries

Question 5

Soleus:

Answer 5

Origin: Head and shaft of fibula, soleal line of tibia

Insertion: Calcaneus via Achilles tendon

Action: Plantar flexion of the ankle

Innervation: Tibial nerve (S1-S2)

Blood Supply: fibular artery, posterior tibial artery

Question 6

Fibularis/Peroneus Longus

Answer 6

Origin: Head and upper portion of fibula

Insertion: Plantar surface of first metatarsal and medial cuneiform

Action: Plantar flexion, eversion, and supports longitudinal arch of foot

Innervation: Superficial peroneal nerve (L5-S1)

Blood Supply: fibular artery

Question 7

Fibularis/Peroneus Brevis

Answer 7

Origin: Lower two-thirds of fibula

Insertion: Base of the fifth metatarsal

Action: Plantar flexion, eversion

Innervation: Superficial peroneal nerve (L5-S1)

Blood Supply: fibular artery

Question 7

Flexor Digitorum Longus

Answer 7

Origin:Posterior surface of the tibia.

Insertion:Base of the distal phalanges of the lateral four toes (second to fifth).

Action:Flexion of the lateral four toes (second to fifth).
Plantar flexion of the foot.

Innervation: Tibial nerve (L5-S2).

Blood Supply: Posterior tibial artery.

Question 8

Tibialis Posterior

Answer 8

Origin: Proximal part of the tibia and fibula.
Interosseous membrane.

Insertion: Navicular bone, medial cuneiform bone, and several metatarsal bases (typically the second through fourth).

Action: Plantar flexion of the foot, inversion of the foot and ankle. Supports the medial longitudinal arch of the foot.

Innervation: Tibial nerve (from the sciatic nerve) - (L4-S3).

Blood Supply: Posterior tibial artery and branches from fibular artery.

Question 9

Flexor Hallucis Longus

Answer 9

Origin: Posterior surface of the fibula.

Insertion: Base of the distal phalanx of the great toe (hallux).

Action: Flexion of the great toe. Plantar flexion of the foot.

Innervation: Tibial nerve (L5-S2).

Blood Supply:Posterior tibial artery.