Principles of Anesthesia

A perioperative ulnar neuropathy that is associated with motor dysfunction (an inability to firmly close the finger against the thumb-- a motion of opposition) suggests a more significant ulnar nerve injury and will recover less quickly than a neuropathy with only sensory loss because

The motor fibers are damaged more easily than sensory fibers Sensory fibers heal more quickly than motor fibers A more significant ischemic injury has occurred if the motor fibers deep in the ulnar nerve are affected The motor fibers are more superficial on the ulnar nerve