Why does a compressed ulnar nerve (ulnar canal syndrome) not cause radial deviation?

Ulnar Nerve. supplies motor innervation to the adductor pollicis muscle in the thumb, the muscles of the hypothenar eminence and the intrinsic muscles of the palm (interossei and lumbricals) The branches to the forearm muscles (extensor and flexor carpi ulnaris when compressed produce only minor weakness (vs what occurs when the nerve is cut) One might develop a claw hand but not radial deviation.