supinator longus reflex

bra·chi·o·ra·di·al re·flex

with the arm supinated to 45°, a tap near the lower end of the radius causes contraction of the brachioradial (supinator longus) muscle. Synonym(s): radioperiosteal reflex, styloradial reflex, supination reflex, supinator jerk, supinator reflex, supinator longus reflex