abductor pollicis brevis
noun
abductor pol·li·cis brev·is
| \ -ˌpäl-ə-səs-ˈbrev-əs
, -ə-kəs-
\
, -ə-kəs-
\
Medical Definition of abductor pollicis brevis
: a thin flat muscle of the hand that abducts the thumb at right angles to the plane of the palm