The ulnar nerve innervates the carpi ulnaris flexor, the flexor digitorum profundus of the third and little fingers and most of the instrinsic muscles of the hand.
Most of the time, ulnar nerve palsy is due to direct nerve wound but it can also occur in fractures-dislocations of the elbow, more exceptionally in wrist fractures-dislocations.
Palsy symptoms are a deficit in little finger flexion and a deficit in mobility for fine hand movements (finger inclination, MP flexion when IP are extended, thumb adduction), combined with hand deformity: ulnar claw. A total loss of sensitivity of the little finger is also found.
Wherever the lesion is sited, emergency surgery will be necessary to stabilize the skeleton in case of fracture-dislocation, or perform an exploration if there is a wound.
In closed injuries, if recovery doesn’t begin 5 months from injury, nerve exploration repair surgery will be necessary.
In paralysis diagnosed late (over a year from injury), a tendon transfer procedure at forearm level will restore flexion for the little finger (synchronization) and tendon transfers at hand level (Zancolli) will improve fine hand motion. Only rarely will the hand’s ulnary edge be treated with sensitive neurotisation.