Autonomic deficits Changes in skin temperature and sweating often accompany peripheral nerve lesions, but are difficult to assess reliably. Tendon reflexes mediated by affected nerves are diminished or absent, unless the lesion spares large sensory fibers that carry the afferent impulse from muscle spindles to the spinal cord. Neuromuscular junction Diseases restricted to the neuromuscular junction obviously produce no sensory symptoms. The diagnosis of disorders affecting the peripheral nervous system affecting the peripheral nervous system begins with localization. These are isolated disturbances of single, named, peripheral nerves, such as the median or peroneal nerves.
Pain can be a prominent complaint.
Mononeuropathies Involvement of a single nerve. Trauma and nerve entrapments are the usual causes. Ulnar nerve Often damaged as it wraps around the elbow, the ulnar nerve supplies sensation to the little and half of the ring finger, and the adjacent portions of the hand. Finger spreading and thumb adduction are weak. Radial nerve Usually compressed in the arm as it winds around the humerus, the radial nerve supplies sensation to the portions of the hand not innervated by median or ulnar nerves, but motor deficits predominate.