Anatomy
Summary
The foot and ankle are composed of numerous bones and joints that work in tandem for locomotion. The tarsal bones include the talus, calcaneus, navicular, cuboid, and medial, intermediate, and lateral cuneiform bones. The foot also has five metatarsal bones as well as phalanges. Notably, digits 2-5 have three phalanges, while the hallux has only two. Two critical joints are the talocrural joint, which permits dorsiflexion and plantarflexion, and the subtalar joint, responsible for ankle inversion and eversion.
Foot pathologies often exhibit characteristic arch changes, such as pes cavus (high arches), often linked to Charcot-Marie-Tooth Disease and Friedreich ataxia, and pes planus (flat arches), commonly seen in obesity and conditions causing ligamentous laxity. The anterior talofibular (ATF) ligament is most susceptible to injury in common ankle sprains, while high ankle sprains usually affect the anterior inferior tibiofibular (AITF) ligament. Other ailments include plantar fasciitis, an inflammation usually attributed to overactivity of the plantar aponeurosis and inadequate foot support. To evaluate suspected foot or ankle fractures, clinicians use the Ottawa ankle rules to determine the need for an X-ray.
Lesson Outline
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FAQs
The foot is composed of a complex structure of bones including the tarsal bones, metatarsal bones, and phalanges. The tarsal bones are a cluster of seven bones in the rear of the foot which includes the calcaneus (heel bone) and talus which supports the leg bones, as well as the navicular bone, medial, intermediate and lateral cuneiform bones, and the cuboid bone. The metatarsals are the long bones in the mid foot while the phalanges are the toe bones. Each of these sets connect to form the overall structure of the foot.
The anterior talofibular (ATF) ligament is the most commonly injured ligament in general ankle sprains. This ligament is located on the outer side of the ankle and is particularly vulnerable when the foot rolls outward, known as inversion. For high ankle sprains, which are less common but often more severe, the anterior inferior tibiofibular (AITF) ligament is most frequently affected. High ankle sprains usually occur due to external rotation or excessive dorsiflexion, often seen in contact sports or activities with abrupt changes in direction.
The metatarsophalangeal joints, often referred to as MTP joints, are where the metatarsal bones of the foot meet the proximal phalanges of the toes. They play a vital role in supporting the weight of the body, as well as in providing flexibility and movement required for actions such as walking or running.
Pes cavus is characterized by an abnormally high arch that does not flatten with weight-bearing and is often associated with conditions like Charcot-Marie-Tooth disease and Friedreich ataxia. On the other hand, pes planus refers to an abnormally flat arch, often associated with obesity or diseases that cause ligamentous laxity.
Plantar fasciitis is a common condition associated with inflammation of the plantar aponeurosis, which connects the calcaneus to the phalanges. When this ligament is strained, often due to overactivity, it can become weak and inflamed, resulting in pain at the bottom of the heel when standing or walking.
