Nerve conduction studies (NCSs) and electromyography (EMG) play key roles in the evaluation of patients with suspected polyneuropathy. Although polyneuropathy has hundreds of potential causes, they can be grouped into several large categories ( Fig. 29.1 ). The first step…
Although nerve conduction and electromyography (EMG) studies are used most often to evaluate peripheral nerve and muscle disorders, they can also be used to evaluate lesions of the cranial nerves. Outside of the brainstem, the cranial nerves, other than cranial…
Patients with pain and numbness in the foot often are referred to the electromyography (EMG) laboratory for evaluation of possible tarsal tunnel syndrome (TTS). TTS results from entrapment of the distal tibial nerve under the flexor retinaculum at the medial…
Isolated lesions of the femoral nerve are uncommon in the electromyography (EMG) laboratory. More common are lesions of the lumbar plexus or L2–L4 nerve roots, which may present with symptoms and signs similar to femoral neuropathy. Especially in milder cases,…
Peroneal neuropathy is one of the most common mononeuropathies in the lower extremity. Most often, peroneal neuropathy occurs at the fibular neck, where the nerve is quite superficial and vulnerable to injury. Patients usually present with a foot drop and…
In the electromyography (EMG) laboratory, the radial nerve is studied less frequently than the median and ulnar nerves and their respective well-known lesions. Nevertheless, entrapment of the radial nerve does occur, often affecting the main radial nerve either in the…
Ulnar neuropathy at the wrist (UNW) is a rare condition that sometimes is confused with ulnar neuropathy at the elbow (UNE) or, more often, with early motor neuron disease. Knowledge of the detailed anatomy of the ulnar nerve at the…
Ulnar neuropathy at the elbow (UNE) is second only to median nerve entrapment at the wrist (i.e., carpal tunnel syndrome [CTS]) as the most common entrapment neuropathy affecting the upper extremity. In contrast to CTS, localizing the site of the…
Proximal median neuropathy is distinctly uncommon compared with median nerve entrapment at the carpal tunnel. Differentiating between median neuropathy at the wrist and more proximal entrapments can be difficult based on clinical grounds alone, especially in mild cases. Electrodiagnostic (EDX)…
Median nerve entrapment at the wrist is the most common of all entrapment neuropathies and, consequently, is one of the most frequent reasons for referral for an electrodiagnostic (EDX) study. In nearly all patients, the usual site of compression occurs…