Pearls

• EMG slowing in the forearm, not in the carpal tunnel

• Tinel's sign in the proximal forearm

• Pain on long finger flexor digi-torum superficialis (FDS) flexion

• Negative Phalen's test

• No nocturnal symptoms

• Numbness of the palmar cutaneous branch of the median nerve

• Pain on resistance to pronation

Diagnostic Studies

Electrodiagnostic tests are suggestive, but not always diagnostic. Although slowing will often show in the forearm, it does not always show in the carpal canal. The threshold testing with Semmes-Weinstein monofilaments may reveal decreased sensibility over the distribution of the median nerve.

Needle electromyography (EMG) may be useful if fibrillations, positive sharp waves, and reduced interference patterns are noted in the pronator quadratus and flexor pollicis longus (FPL). It is important to note that the EMG does not differentiate median nerve lesions at the pronator teres from those more proximal.

Differential Diagnosis

Carpal tunnel syndrome Compartment syndrome Pronator syndrome

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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