Foot

From ArticleWorld

The foot is the most distal aspect of the human leg and of the hind leg of many other mammals. In humans, the foot is the portion of the leg that makes contact with the ground during ambulation.

Anatomy

The foot in humans is made of multiple bones that form a flattened portion that ends in five digits or toes. The calcaneus and the talus bone form the heel and the ankle. Several irregular bones are arranged just distal to the calcaneus. They are the navicular bone, the medial, intermediate and lateral cuneiform bones and the cuboid bones. Five metatarsals extend as small long bones to connect to the toes.

Each toe has small bones that articulate the toes, even though the need for their articulation is not as much as their counterparts in the hand. There are three phalanges in the second through fifth toes. The great or first toe is made of only two phalanges.

Multiple ligaments help keep the foot stable. A large plantar ligament supports the heel of the foot. Multiple smaller ligaments support the small bones of the foot and each joint in the foot. A large area of connective tissue called the plantar fascia begins at a bony prominence at the base of the calcaneus and spreads across the bottom of the foot toward the toes.

Function

Some of the movements of the toes, especially those of the great toe, are due to muscles that originate in the calf. These muscles have very long tendons that move through fibrous bands such as the superior or inferior extensor retinaculum to reach the toes.

The flexor digitorum brevis muscle is a broad muscle at the bottom of the foot that helps flex the toes. The abductor hallucis muscle and the abductor digiti minimi muscles allow the first and fifth toes to draw away from the foot.

The extensor hallucis muscle is located on the top of the foot and allows one to raise the big toe by itself. The bulk of the extensor function (dorsiflexion) of the top of the foot is from tendons along the top of the foot that originate above the ankle.

Conditions

The injuries to the foot include fracture or dislocation of one or more phalanges. A blunt trauma to the foot can result in a fracture of one or more of the metatarsal bones. Fortunately they are well protected by the flesh of the foot and often heal without difficulty. Another common condition of the foot is called plantar fasciitis. This involves an inflammation of the connective tissue on the bottom of the foot. In severe cases, it can result in a bony spur at the base of the calcaneus.