extensor hoods
composition
- tendons of extensor digitorum
- tendons of extensor pollicis, digiti minimi, pollicis brevis
copied shamelessly from Gray's
Each extensor hood is triangular, with:
- the apex attached to the distal phalanx,
- the central region attached to the middle phalanx (index, middle, ring, and little fingers) or proximal phalanx (thumb), and
- each corner of the base wrapped around the sides of the
- metacarpophalangeal joint—in the index, middle, ring, and little fingers, the corners of the hoods attach mainly to the deep transverse metacarpal ligaments; in the thumb, the hood is attached on each side to muscles.
Because the intrinsic muscles are attached to the free edge of the extensor hood, contraction causes:
- flexion at MCPJ
- extension at DIPJ and PIPJ
