NCIt definition : A muscle in the posterior forearm that originates from the posterior surface of the
middle third of the ulna and the adjacent interosseous membrane and attaches to the
posterior surface of the base of distal phalanx of the thumb; it functions to extend
the thumb at the metacarpophalangeal and interphalangeal joints and extend and abduct
the wrist joint.;
Alternative definition : CDISC: A muscle of the forearm, in general extending from the posterior surface of
the middle third of the ulna and the adjacent interosseous membrane to the posterior
surface of the base of the distal phalanx of the thumb; primary function is to extend
the thumb at the metacarpophalangeal and interphalangeal joints and extend and abduct
the wrist joint.;