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.