Topic Overview

Phalanges

General Features

• Skeleton of the digits (fingers and thumb).

• Each finger has 3 phalanges (proximal, middle, distal), except the thumb, which has 2 (proximal and distal).

• Total = 14 phalanges in one hand.

• Structure:

  • Base (proximal end) → articulates with metacarpal or phalanx.

  • Shaft → cylindrical, tapering distally.

  • Head (distal end) → rounded in proximal/middle phalanges; distal phalanx has expanded tuft (supports pulp of finger and nail bed).

Clinical Anatomy of Phalanges

• Fractures

  • Very common due to crushing or direct trauma.

  • Can lead to stiffness and deformity because of close relation to tendons.

• Mallet finger

  • Avulsion fracture at base of distal phalanx → extensor tendon pulled off, fingertip droops.

• Jersey finger

  • Avulsion of flexor digitorum profundus tendon from distal phalanx → inability to flex fingertip.

• Tuft fractures

  • Common in distal phalanx (from crush injuries).

• Congenital anomalies

  • Clinodactyly (curved finger).

  • Brachydactyly (short phalanges).

• Clinical landmark

  • Tufts of distal phalanges important for finger pad and nail attachment.

Ossification of Phalanges

• Each phalanx ossifies from two centers:

  1. Primary center → for shaft, appears in 8th–12th week intrauterine life.

  2. Secondary center → for base, appears around 2 years of age.

• Fusion → by 18 years.

• Special note:

  • Distal phalanges ossify earlier than proximal ones (reverse of normal long bone order).

  • Distal phalanges start ossifying by 8th week IUL, others follow later.