metatarsal

Metatarsal refers to any of the five long bones of the forefoot that connect the tarsal bones of the hind- and midfoot to the proximal phalanges of the toes. They are numbered I to V from medial (the big toe side) to lateral.

Anatomy: Each metatarsal consists of a proximal base, a shaft, and a distal head. The bases articulate with the distal tarsal bones: the first with the medial cuneiform; the second with the intermediate and lateral cuneiforms; the third with the lateral cuneiform; and the fourth and fifth with the cuboid. The distal heads articulate with the proximal phalanges at the metatarsophalangeal joints. The first metatarsal is typically the strongest and supports the great toe, while the second is often the longest. The metatarsal shaft length and curvature vary among individuals.

Function: The metatarsals transmit body weight from the ankle to the toes during standing and gait and serve as lever structures for push-off. They help form the transverse and longitudinal arches of the foot and contribute to stability and balance.

Clinical relevance: Metatarsals are a common site of injury. Acute fractures can involve the shaft, neck, or base, with fifth metatarsal fractures (often at the proximal diaphysis) and Lisfranc injuries among notable examples. Overuse injuries include metatarsalgia, pain concentrated under the heads of the metatarsals. Treatment ranges from rest and immobilization to surgical repair, depending on the location and severity.

Development: Metatarsals arise from primary ossification centers in the shafts before birth; secondary centers appear near the ends in childhood. The fifth metatarsal often has an apophysis at the base that serves as a tendon attachment in adolescence.