Anatomical Relations
Each extensor tendon is held in place by a fibrous extensor expansion, which runs from the metacarpophalangeal joint into each digit. Extensor hood is the proximal portion of the extensor expansion, covering the metacarpophalangeal joint and extending onto the proximal phalanx. The expansions form movable hoods over the dorsal aspect of the digits.
Structure
The extensor hood is a component of the distal fascial complex. This superficial fascia of the digits contains both fibrous and adipose tissue in both palmar and dorsal aspects. The lateral condensations of the fascia forms the lateral digital sheets.
Function
The extensor expansions keep the extensor digits in place and ensure their insertion into the phalanges. They are also the site of insertion for other intrinsic muscles of the hand.
References
Chrysopoulo, M. T., McGrouther, D. F., Jeschke, M. G. and Kaufman, B. R. (2002) 'Cleland's ligaments: an anatomic study', Plast Reconstr Surg., 109(2), pp. 566-72.
