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.

supinator longus reflex

[so̅o̅′pinā′tər]
Etymology: L, reflectere, to bend back
a contraction of the brachioradialis muscle, causing flexion at the elbow joint, on tapping the point of insertion of the supinator longus muscle at the lower end of the radius. Also called radial reflex, supinator jerk reflex.