Deep group of muscles in the posterior compartment of the lower leg

Question 1

Popliteus

Answer 1

Origin:

• Lateral femoral condyle

Insertion:

• Posterior surace of proximal tibia

Innervation:

• Tibial nerve (L4 to S1)

Function:

• Stabilises knee joint (resists lateral rotation of tibia on the femur).
• Unlocks knee joint (laterally rotates femur on fixed tibia).

Question 2

Flexor hallucis longus

Answer 2

Origin:

• Posterior surface of fibula and adjacent interosseous membrane

Insertion:

• Plantar surface of distal phalanx of great toe

Innervation:

• Tibial nerve (S2, S3)

Function:

• Flexes great toe

Question 3

Flexor digitorum longus

Answer 3

Origin:

• Medial side of posterior surface of the tibia

Insertion:

• Planter surfaces of bases of distal phalanges of the lateral four toes

Innervation:

• Tibial nerve (S2, S3)

Function:

• Flexes lateral four toes

Question 4

Tibialis posterior

Answer 4

Origin:

• Posterior surfaces of interosseous membrane and adjacent regions of tibia and fibula

Insertion:

• Mainly to tuberosity of navicular and adjacent region of medial uniform

Innervation:

• Tibial nerve (L4, L5)

Function:

• Inversion and plantar flexion of foot, support of medial arch of foot during walking