Basic Foot and Ankle Anatomy - Muscles and Fascia

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Description

Muscles are responsible for the movement and the primary source of the ankle and foot injury is a movement performed excessively, repetitively, and for a long duration that exceeds tissue capabilities.Weight bearing is a primary function of the foot and ankle and together, these two structures often have different responsibilities in order for this task to be completed. What is expected from them is a quick transformation from being flexible to adapt to the ground to becoming very rigid to propel the body forward. Other functions include maintaining balance, upright posture and recognising body position in space.

Lower Leg Muscle

The lower leg muscles are divided into four compartments: the superficial posterior compartment, the deep posterior compartment, the lateral compartment, and the anterior compartment.

Posterior Compartments

The primary plantar flexors of the ankle are located in this compartment. Because of its insertion medial to the midline of the foot, they also function as supinators.

Primary responsibilities include:

• transforming the foot into a rigid lever
• assisting with push-off during the gait cycle
• controlling tibia progression over the foot during initial contact through push-off gait cycle
• controlling foot pronation during initial contact through push-off gait cycle

Superficial Posterior Compartment

Soleus

Gastrocnemius

Plantaris

Deep Posterior Compartment

Flexor digitorum longus

Tibialis posterior

Flexor hallucis longus

Popliteus

Lateral Compartment

Peroneus (Fibularis) Longus Origin:Head and superior 2/3 of  lateral surface of the fibula. Insertion: base of the 1st metatarsal and medial cuneiform;Nerve supply: superficial fibular nerve (L5 - S1)

Function:

• Ankle inversion and week plantaflexion
• Muscular control of the forefoot position

Peroneus (Fibularis) Brevis Origin: Inferior 2/3 of lateral surface of the fibula. Insertion: base of the 5th metatarsal.

Function:

• Ankle inversion and week plantaflexion
• Stabilises the lateral column of the foot

Anterior Compartment

Tibialis Anterior

Extensor Digitorum Longus

Extensor Hallucis Longus

Peroneus Tertius

Clinical relevance

1. Area posterior to the medial malleolus tends to get injured frequently causing tendon injury of the posterior tibialis, flexor hallucis longus or flexor digitorum and tibial nerve compression.