This document discusses the median and ulnar nerves. It describes the origin, course, branches, and termination of these nerves in the arm, forearm, and hand. It also discusses clinical conditions related to lesions of these nerves, including carpal tunnel syndrome, claw hand, and ape hand deformity. The median nerve is particularly involved in carpal tunnel syndrome due to its course through the carpal tunnel. Lesions of the median nerve above the elbow can result in an ape hand deformity from paralysis of thenar muscles. Lesions of the ulnar nerve commonly cause claw hand deformity from paralysis of intrinsic hand muscles.