Pronator teres syndrome is a compression neuropathy of the median nerve at the elbow. It is rare compared to compression at the wrist (carpal tunnel syndrome) or isolated injury of the anterior interosseous branch of the median nerve (anterior interosseous syndrome). Symptoms
Compression of the median nerve in the region of the elbow or proximal part of the forearm can cause pain and/or numbness in the distribution of the distal median nerve, and weakness of the muscles innervated by the anterior interosseous nerve: the flexor pollicis longus ("FPL"), the flexor digitorum profundus of the index finger ("FDP IF"), and the pronator quadratus ("PQ"). The pain tends to be at the wrist joint, in the distribution of the terminal branch of the anterior interosseous nerve, and is exacerbated by sustained pronation (i.e., wrist down). The weakness of the FPL and FDP IF is painless, but causes people to "drop things" and have a sense of loss of dexterity. Pinching with the wrist flexed magnifies the expression of this weakness, by reducing resting tension on the muscles of pinch. For instance, "child-proof" prescription pill bottles may be difficult to open.
Dantrolene is a muscle relaxer that decreases the symptoms of BD by inhibiting Ca2+ release channels in the sarcoplasmic reticulum, while verapamil sequesters Ca2+ in the sarcoplasmic reticulum of muscle cells by functioning as a Ca2+ channel blocker.These drugs act by limiting the amount of Ca2+ from being released from the sarcoplasmic reticulum. When a muscle is stimulated, Ca2+ is released from the sarcoplasmic reticulum into the cytoplasm where it binds to a protein called troponin. This event allows the muscle fibers to overlap, causing a contraction. In BD, Ca2+ levels are high in the cytoplasm, which means Ca2+ can readily bind troponin, leading to muscles that are in an extended state of contraction. References


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