The distal phalanges, as compared with the distal phalanges of the finger, are smaller and are flattened from above downward; each presents a broad base for articulation with the corresponding bone of the second row, and an expanded distal extremity for the support of the nail and end of the toe. Distal phalanx
In the hand, the distal phalanges are flat on their palmar surface, small, and with a roughened, elevated surface of horseshoe form on the palmar surface, supporting the finger pulp.: 6b. 3. The Phalanges of the Hand  The flat, wide expansions found at the tips of the distal phalanges are called apical tufts. They support the fingertip pads and nails. The phalanx of the thumb has a pronounced insertion for the flexor pollicis longus (asymmetric towards the radial side), an ungual fossa, and a pair of unequal ungual spines (the ulnar being more prominent). This asymmetry is necessary to ensure that the thumb pulp is always facing the pulps of the other digits, an osteological configuration which provides the maximum contact surface with held objects.In the foot, the distal phalanges are flat on their dorsal surface. It is largest proximally and tapers to the distal end. The proximal part of the phalanx presents a broad base for articulation with the middle phalanx, and an expanded distal extremity for the support of the nail and end of the toe.: 6b. 3.
The arboreal specialization of these terminal phalanges makes it impossible for the sloth to walk on the ground where the animal has to drag its body with its claws. Additional images
See also
Hand
Foot

References
External links

MedTerms.com Medical Dictionary