Muscles - Leg (Lateral Compartment)

Question 1

What are the borders of the lateral compartment?

Answer 1

Anteriorly - anterior intermuscular septum

Posteriorly - posterior intermuscular septum

Medially - fibula

Laterally - deep fascia of the leg

Question 2

What is the function of these muscles?

Answer 2

Eversion - turning the sole of the foot outwards

Question 3

Fibularis brevis

Answer 3

Origin - inferolateral surface of the fibular shaft.

Insertion - muscle belly forms a tendon - descends with the fibularis longus into the foot. Travels posteriorly to the lateral malleolus, passing over the calcaneus and the cuboidal bones, inserting onto metatarsal V.

Innervation - superficial fibular nerve (L4-S1).

Actions - eversion of the foot.

Question 4

Innervation of these muscles?

Answer 4

Superficial fibular nerve

Question 5

What are the two muscles of the lateral compartment?

Answer 5

Fibularis longus and brevis.

Question 6

Clinical relevance - locating the common fibular nerve

Answer 6

The fibularis longus can be used as an anatomical landmark to identify this nerve.

There is a small gap between the fibularis longus, and the head and neck of the fibula. The common fibular nerve passes through this gap.

After passing through this gap, the common fibular nerve branches off into the superficial and deep fibular nerves.

Question 7

Fibularis longus

Answer 7

Origin - superior and lateral surface of fibula; lateral tibial condyle

Insertion - fibres converge into a tendon - tendon passes posterior to the lateral malleolus - tendon crosses under the foot - attaches to the medial side of the medial cuneiform and the base of metatarsal I.

Innervation - superficial fibular nerve (L4-S1)

Actions - Eversion and plantarflexion of the foot. Support lateral and transverse arches of the foot.