Ankle and Foot

Anatomy 

The ankle is the part of the lower limb encompassing the distal portion of the leg and proximal portions of the foot. The ankle encompasses the ankle joint, an articulation between the tibia and fibula of the leg and the talus of the foot, which is described in more detail here. 

The foot is the part of the lower limb distal to the ankle joint. It is covered on its dorsal surface by loosely adherent skin and on its plantar/inferior surface by thick hairless skin that is tough and strongly adherent to the underlying plantar aponeurosis. The foot contains 26 small bones that are designed for weight bearing and force distribution. The bony alignment creates three arches the provide efficient weight distribution while avoiding compression of plantar neuro-vascular structures. The three arches, medial and lateral longitudinal and the transverse arch together create an architectural vault, which is one of the strongest load-bearing structures known to mankind.

Bones

The bones of the foot are named as follows

The tarsals  

             Talus

             Calcaneus

             Navicular

             Cuboid

             Cuneiforms - medial, intermediate and lateral

The metatarsals - numbered from medial or first (big toe), to lateral or fifth (little toe)

The phalanges - toes 2-5 each have 3 phalanges. The first or Big toe (hallux) has only two


Muscles

The dorsum of the foot has only one muscle (maybe 2 depending on classification). This is the extensor digitorum brevis (some authors name the most medial part of this muscle extensor hallucis brevis). Tendons are the main collagenous structures in the dorsum. The tendons connect anterior/dorsiflexor compartment muscles of the leg to the foot bones.

The plantar aspect of the foot contains the tough fibrous plantar aponeurosis covering muscles and tendons arranged in 4 layers, numbered from 1 superficial to 4 deep.

Layer 1 consists of the Abductor didgiti minimi, Flexor digitorum brevis, Abductor hallucis

Layer 2 consists of the Quadratus plantae, the Lumbricals, and the long tendons of Flexor digitorum longus and Flexor hallucis longus

Layer 3 consists of the Flexor hallucis brevis, Adductor hallucis and Flexor digiti minimi brevis

Layer 4 consists of the Interosseous muscles and the long tendons of Peroneus/fibularis longus and Tibialis posterior


Neurovasculature

Cutaneous innervation of the dorsum is by the superficial and deep peroneal/fibular nerves

Cutaneous innervation of the plantar aspect is by the medial and lateral planter and tibial nerves

Dorsal motor innervation is by the deep peroneal nerve to extensor digitorum brevis and extensor hallucis brevis)

Plantar motor innervation is via the medial and lateral plantar nerves (terminal branches of the tibial nerve)

Arteries crossing into the foot accompany nerves of corresponding names. Therefore the anterior tibial or 'dorsalis pedis' artery, and the posterior tibial artery, are the terminal branches of the medial and lateral plantar arteries.

Clinical Examination

Conditions


Procedures

Interventions