The distal (third) phalanx differs between species to conform to the hoof or to the claw that encloses it. They have in common a an articular facet, a parietal surface and solar surface.
The solar surface of the distal phalanx is situated palmarly.
In horses, the solar surface is separated from the parietal surface by the solar border. A rough semilunar line separates the solar surface into a dorsal part (planum cutaneum) and a plamarl flexor surface for the insertion of the deep digital flexor tendon. On either side of the flexor surface are the medial and lateral solar grooves which lead to the medial and lateral solar foramina (communicating each other by the U-shaped solear canal).