]> 2026-07-31T07:51:30+00:00 WBR0489 0 en Median nerve The median nerve is not typically damaged in Klumpke palsy. However, patients with Klumpke palsy will frequently exhibit weakness of the thenar eminence, which is innervated by the median nerve. These muscles are innervated by the nerves passing through the median nerve from the C8-T1 nerve roots. Radial nerve The radial nerve is not typically damaged in Klumpke palsy. The radial nerve can be injured in Erb palsy, where the superior trunk of the brachial plexus is injured. Erb palsy causes a “waiter’s tip” appearance of the arm and hand. Ulnar nerve While the ulnar nerve originates from the C8-T1 nerve roots, the ulnar nerve itself is not damaged in Klumpke palsy. A lesion of the ulnar nerve can be caused by a fracture of the medial epicondyle of the humerus, giving rise to the “ulnar claw”. In this condition, the fourth and fifth digits flex when attempting to open the hand. C5-C6 nerve roots C5 and C6 nerve roots (and occasionally C7 nerve root) are damaged in Erb palsy, which is characterized by failure to abduct, laterally rotate, supinate, and flex the arm. C8-T1 Klumpke palsy results from an injury of the C8-T1 nerve roots. Anatomy E Musculoskeletal/Rheumatology General Principles 2020-10-28T00:44:24Z 2459150.5308333 WBR0489