Fingertip Injuries

Excerpt

The fingertip is the most distal portion of the finger providing the tactile and sensory functions that are then relayed to the brain. It is anatomically defined as the portion of finger distal to the insertion of the flexor digitorum superficialis and extensor tendons on the distal phalanx, or the interphalangeal joint when referring to the thumb. The neurovascular supply of the fingertip is via digital arteries and nerves which trifurcate near the distal interphalangeal joint.

The volar pulp is supplied by specialized sensory Pacinian, Meissner corpuscles, and Merkel cells which provide detailed discrimination of touch and feel sensations. Fingerprints present on the volar surface comprise a uniquely individualized pattern formed by grooves and ridges. The dorsal surface consists of the nail fold, nail bed, and nail plate. Additional descriptions of the dorsal surface based on relationship to the nail are as follows: eponychium soft tissue just proximal to the nail, paronychium lateral nail folds, and hyponychium. The hyponychium is a plug of keratinous material situated beneath the distal edge of the nail where the nail bed meets the skin. The lunula white portion of the proximal nail demarcates the sterile area from the germinal matrix beneath. The nail bed is divided into the sterile matrix where the nail adheres, and the germinal matrix proximal to the sterile matrix; the latter is responsible for 90% of nail growth.