Fifth metatarsal bone

As with the four other metatarsal bones it can be divided into three parts; a base, body and head. The base is the part closest to the ankle and the head is closest to the toes. The narrowed part in the middle is referred to as the body (or shaft) of the bone. The bone is somewhat flat giving it two surfaces; the plantar (towards the sole of the foot) and the dorsal side (the area facing upwards while standing). These surfaces are rough for the attachment of ligaments. The bone is curved longitudinally, so as to be concave below, slightly convex above.

The base articulates behind, by a triangular surface cut obliquely in a transverse direction, with the cuboid; and medially, with the fourth metatarsal. The fifth metatarsal has a rough eminence on the lateral side of its base, known as the tuberosity or the styloid process. The plantar surface of the base is grooved for the tendon of the abductor digiti quinti.

The head articulates with the fifth proximal phalanx, the first bone in the fifth toe.

A strong band of the plantar aponeurosis connects the projecting part of the tuberosity with the lateral process of the tuberosity of the calcaneus.

Proximal fractures

Proximal fractures of the fifth metatarsal are common, and are distinguished by their locations:

• A proximal diaphysis fracture is typically a stress fracture, commonly among athletes.
• A metaphysis fracture is also called a Jones fracture. Due to poor blood supply in this area, such a fracture sometimes does not heal and surgery is required.
• A tuberosity fracture is also called a pseudo-Jones fracture or a dancer's fracture. It is typically an avulsion fracture.

Normal anatomy that may simulate a fracture include mainly:

• The "apophysis", which is the secondary ossification center of the bone, and is normally present at 10 – 16 years of age.
• Os vesalianum, an accessory bone which is present in between 0.1 - 1% of the population.