Phalanges of the hand

Study entry

Parts

Fourteen phalanges: three (proximal, middle and distal) in each finger and two in the thumb. Each with a base, shaft and head; the distal one ends in the tuberosity, under the pulp and the nail.

Joints

Metacarpophalangeal and proximal and distal interphalangeal (only one interphalangeal in the thumb).

Clinical

Avulsion of the extensor tendon at the base of the distal phalanx leaves the tip of the finger drooping (mallet finger).

Source: cap. 3, «Huesos de la mano» y cuadro clínico

Clinical correlation

Fracture of the phalanges

Crushing of the distal phalanx (finger caught in a door) is very painful, because of the sensitivity of the fingers; the fracture is usually comminuted and forms a painful hematoma. The proximal and middle phalanges break by crushing or hyperextension; because they lie next to the flexor tendons, the fragments must be well aligned for the finger to work again.

Mallet finger

A sudden tension on the long extensor tendon may tear off part of its attachment at the base of the distal phalanx, for example when a baseball hits the fingertip and forces the distal interphalangeal joint into flexion while the finger tries to extend. Afterward, the person cannot extend the distal interphalangeal joint, and the finger resembles a hammer.

Related clinical cases

• Fracture of the phalanges
• Mallet finger

Other structures in this region

• Clavicle
• Scapula
• Humerus
• Radius
• Ulna
• Scaphoid
• Lunate
• Triquetrum