Extensor process

The middle phalanx (second phalanx, os coronale) is shorter but very similar to the proximal phalanx. It is subdivided in a base with articular facet, a body (shaft) and a head (distal extremity).

In horses, the dorsal articular cavity (fovea articularis) is divided by a sagittal ridge the corresponds to the distal trochlea of the proximal phalanx. Its dorsal border is elevated to form the extensor process and the palmar border is thickened to form a transverse prominence called the flexor tuberosity.