Answer;
-Palmar
The bottom of a horse's front hoof is the palmar surface.
Step-by-step explanation;
-The external surface at the front of the foot is its dorsal surface and that surface facing the ground is its solar surface. On the front leg the caudal aspect of the foot is its palmar surface, whereas on the back leg it is referred to as the plantar surface.
-Medial and lateral are directional terms that refer to the portions of the foot either nearest the foot on the opposite side (medial) or farther away (lateral) from the opposite foot.