Extensor expansion of hand

The extensor expansion of hand (dorsal digital expansion) is the triangular complex by which the extensor tendon inserts onto the phalanges. According to the terminologia anatomica 2, the extensor expansion of hand is composed by:

• The extensor hood (note that some authors use this term as a synonym of the dorsal digital expansion)

• Central band of extensor expansion of hand

• Collateral bands of extensor expansion of hand 

Some authors also include the retinacular ligaments in the extensor expansion of hand.

The extensor expansion of hand serves to hold the extensor tendons in place and allow the extensors, lumbricals, and interossei to effect extension at the proximal and distal interphalangeal joints.