Ulnar Nerve

Ulnar nerve damage results in difficulty flexing the wrist and a striking inability to flex the metacarpal phalangeal joint of the fourth and fifth fingers.Long-standing ulnar nerve damage produces a partial claw hand because the damage is restricted to the lumbricoids of the small and ring fingers while sparing those of the middle and index fingers. The lumbricoids of the second and third fingers are innervated by the median nerve. Neonates with Klumpke palsy have a complete claw hand due to weakness of all the lumbricoid muscles. Ulnar nerve lesions are very rare in neonates.