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