The thumb extensor tendons are maintained in a central position at the
metacarpophalangeal joint level by radial and ulnar attachments to the
Sagittal bands. At this level, the
extensor pollicis brevis lies radial to the
extensor pollicis longus and attaches to the dorsal base of the
proximal phalanx. Radial and ulnar tendon slips from the
Abductor Pollicis Brevis and the
Adductor Pollicis muscles, respectively, and the
extensor pollicis longus join the extensor hood to form the
Terminal tendon. This crosses the dorsal surface of the
interphalangeal joint to attach to the dorsal base of the
distal phalanx.
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