Outside the peripheral nerve trunk there is a conjunctive like "adventitia" that permits an excursion of the nerve trunk which is a feature of normal nerve functioning during, for example, joint movements. Such an extraneural gliding surface together with the normally occurring sliding of fascicles against each other in deeper layers—intraneural gliding surfaces—make the normal gliding of the nerve possible. The median and ulnar nerve may glide 7.3 and 9.8 mm respectively during full elbow flexion and extension, and the extent of excursion of the nerve just proximal to the wrist is even more pronounced (14.5 and 13.8 mm respectively) (Wilgis and Murphy 1986). In relation to the flexor retinaculum the median nerve may move up to 9.6 mm during wrist flexion and to a slight degree in wrist extension but the nerve also moves during finger moments (Millesi et al. 1990).
The epidemiologic evidence linking repetitive loading to nerve injuries will be reviewed elsewhere. The purpose of this report is to review human and animal studies which examine the physiologic, pathophysiologic, biochemical and histologic effects of loading on the peripheral nerve.
The database PubMed was searched on August 3, 1998 for peer-reviewed articles from scientific journals from 1965 to 1998 using the following query:
(((("nerve compression syndromes/etiology" [MeSH Major Topic]
OR "nerve compression syndromes/pathology" [MeSH Major Topic] )
OR "nerve compression syndromes/physiopathology" [MeSH Major Topic] )
OR Nerve Compression Syndromes/prevention and control [MeSH Terms] ))
OR ("hand arm vibration syndrome" AND nerve))
The search produced 3025 citations. On a case by case review, the following citations were eliminated: case reports, reviews, surgical techniques or complications, nerve crush studies, and nerve conduction techniques. All citations with titles suggesting study of physical exposures, loading, vibration, etiology, mechanisms of injury, biological response, and histology were retained. Total citations identified: 190.
In addition, the files of the authors were searched and a request was made to the seven discussants of this topic to provide 5 to 10 key citations. One discussant responded and provided 5 citations. These citations had been captured by the PubMed query, providing some confidence in the database search.
Various methods have been used to induce an acute or chronic compression of a peripheral nerve in animal models. There are advantages and disadvantages with all used methods. For acute compression, tourniquets can be used to apply compression around, for example, the hind limb of