Location, location, dislocation

摘要

Many of us have been taught to think of nerves as fixed structures that occupy a defined piece of anatomic real estate. And like housing, high importance is placed on location, as one of the goals of electrodiagnosis is to localize nerve pathology to provide insight into etiology. However, unlike housing, nerves do move around, a phenomenon sometimes overlooked during routine testing. For example, in the carpal tunnel, the median nerve moves deep to the tendons with wrist flexion, and slides distally and proximally with flexion and extension of the fingers (Walker et al., 2004). With nerve transection, the innate distal-proximal tension on the nerve causes a nerve gap to appear between its separated ends (Cart-wright et al., 2007). And, of course, with elbow flexion, ulnar nerve subluxation or dislocation can occur. Real-time neuromuscular ultrasound is a simple non-invasive method to evaluate the movement of nerve, and in this issue Dr. Granata and colleagues used this technology, in combination with EMG and nerve conduction studies, to evaluate ulnar nerve function in patients with Ehlers-Danlos syndrome (Granata et al., 2013).