Extensor hood

Extensor expansion
Tendons of forefinger and vincula tendina. (Extensor expansion not labeled, but region is visible.)
Anatomical terminology []

An extensor expansion (dorsal expansion, dorsal hood, dorsal aponeurosis) is the special connective attachments by which the extensor tendons insert into the phalanges.

These flattened tendons (aponeurosis) of extensor muscles span the proximal and middle phalanges.

At the distal end of the metacarpal, the extensor tendon will expand to form a hood, which covers the back and sides of the head of the metacarpal and the proximal phalanx.

The expansion soon divides into three bands: