Posterior Leg

Question 1

Gastrocnemius

Answer 1

Origin: Distal femur

Insertion: Calcaneal tuberosity via calcaneal tendon

Action: Knee flexion, talocrural plantarflexion

Innervation: Tibial nerve (S1, S2)

Question 2

Soleus

Answer 2

Origin: Proximal tibia, fibular head

Insertion: Calcaneal tuberosity via calcaneal tendon

Action: Talocrural plantarflexion

Innervation: Tibial nerve (S1, S2)

Question 3

Plantaris

Answer 3

Origin: Lateral supracondylar ridge of femur

Insertion: Calcaneal tuberosity

Action: Talocrural plantarflexion, (weak knee flexion)

Innervation: Tibial nerve (S1, S2)

Question 4

Popliteus (deep posterior)

Answer 4

Origin: Lateral femoral condyle

Insertion: Posterior proximal tibia

Action: Medial rotation of tibia to unlock knee, weak knee flexion

Innervation: Tibial nerve (L4-S1)

Question 5

Tibialis Posterior (deep posterior)

Answer 5

Origin: Tibia, fibula, interosseous membrane

Insertion: Mainly navicular tuberosity and medial cuneiform

Action: Foot inversion, talocrural plantarflexion

Innervation: Tibial nerve (L4, L5)

Question 6

Flexor Digitorum Longus (deep posterior)

Answer 6

Origin: Posteriomedial tibia

Insertion: Distal phalanges 2-5

Action: Digits 2-5 flexion (MTP, PIP, DIP), talocrural plantarflexion

Innervation: Tibial nerve (S2, S3)

Question 7

Flexor Hallucis Longus

Answer 7

Origin: Fibula, interosseous membrane

Insertion: Distal phalanx hallux

Action: Hallux flexion (1st MTP, IP), talocrural plantarflexion
[prevents uncontrolled/excessive hyperextension; stabilises hallux]

Innervation: Tibial nerve (S2, S3)