Femoral Neuropathy
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…
Ulnar Neuropathy at the Wrist
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…
Proximal Median Neuropathy
Proximal median neuropathy is distinctly uncommon compared with median entrapment at the carpal tunnel. Differentiating between median neuropathy at the wrist and more proximal entrapments can be difficult based on…
Clinical–Electrophysiologic Correlations: Overview and Common Patterns
The value of information gained from electrodiagnostic (EDX) studies relies on correct data collection and, even more importantly, correct data interpretation. Mastering the technical aspects of routine nerve conduction studies…
Routine Upper Extremity, Facial, and Phrenic Nerve Conduction Techniques
Median Motor Study ( Figure 10–1 ) Recording Site: Abductor pollicis brevis (APB) muscle (lateral thenar eminence): G1 placed over the muscle belly G2 placed over the first metacarpal-phalangeal joint…
Basic Electromyography: Analysis of Spontaneous Activity
The recognition of abnormal spontaneous activity is one of the most important parts of the needle electromyography (EMG) examination. The presence of abnormal spontaneous activity on EMG can yield several…
Artifacts and Technical Factors
Understanding and recognizing artifacts and technical factors play a central role in every nerve conduction and electromyography (EMG) study ( Box 8–1 ). The value of the information gained during…
Basic Electromyography: Analysis of Motor Unit Action Potentials
After assessment of insertional and spontaneous activity, the needle electromyography (EMG) examination moves on to the evaluation of motor unit action potentials (MUAPs). In a process similar to the analysis…
Basic Nerve Conduction Studies
After the history is taken and a directed physical examination is performed, every study begins with the nerve conduction studies (NCSs). The needle electromyography (EMG) examination is performed after the…
Routine Lower Extremity Nerve Conduction Techniques
Tibial Motor Study ( Figure 11–1 ) Recording Site: Abductor hallucis brevis (AHB) muscle: G1 placed 1 cm proximal and 1 cm inferior to the navicular prominence G2 placed over the metatarsal–phalangeal…
