Metatarsal I

The metatarsal bones are typically five long bones at the distal end of the pelvic limb. They are sometimes called pelvic metapodium. The skeleton of the metatarsus (and phalanges) closely ressembles those of the forelimb (metatarsals are longer and slender with a stronger cortex, and in horses, the cannon bone (metatarsal III) is circular (oval in thoracic limb)).

The metatarsal bones are numerated in a mediolateral sequence from MtI to MtV.

The metatarsal bones have all the same segments:

• A proximal extremity (base) bearing a tarsal articular surface for the distal row of the tarsal bones and additional facets towards its neighbors.
• A shaft (body) with a plantar and a dorsal surface, and medial and lateral surfaces.
• A distal extremity (head) with a trochlea that articulates with the proximal phalanx.

The number of metatarsal bones may be reduced. For example, in the horse, only the third ray (cannon bone) is functional, with second and fourth metacarpal bones (splint bones) bearing no weight.