The extensor expansion ligament is described as a small, triangular, flat aponeurosis covering which part of the fingers?

The extensor expansion ligament is described as a small, triangular, flat aponeurosis covering which part of the fingers?

• A. Distal phalanx
• B. Proximal phalanx
• C. Middle phalanx
• D. Metacarpal base

Answer: (B)

The extensor expansion (extensor hood) is a thin, triangular aponeurosis that sits on the dorsum of the proximal phalanx just beyond the metacarpophalangeal joint. This position lets the extensor digitorum tendon spread into the hood and anchor to the middle and distal phalanges via central slips and lateral bands, distributing extension force along the finger. Because it overlays the proximal phalanx, that part of the finger is the correct covering described. It does not extend over the distal phalanx or the metacarpal base in the same way.

The extensor expansion (extensor hood) is a thin, triangular aponeurosis that sits on the dorsum of the proximal phalanx just beyond the metacarpophalangeal joint. This position lets the extensor digitorum tendon spread into the hood and anchor to the middle and distal phalanges via central slips and lateral bands, distributing extension force along the finger. Because it overlays the proximal phalanx, that part of the finger is the correct covering described. It does not extend over the distal phalanx or the metacarpal base in the same way.