[Study on the intraneural topography of the brachial plexus].

An accurate intraneural topography of the nerve fascicules in the brachial plexus provides a correct diagnosis and proper treatment of brachial nerve injuries. Four specimens of the branchial plexus were harvested from human cadavers by careful dissection and serially cross-sectioned from the nerve root level to the peripheral nerve. A spatial relationship between each nerve fascicule was observed and traced proximo-distally with a stereoscopic microscope. The main results and conclusions are as follows: 1. Four types of normal variation were identified in the composing elements of the brachial plexus. It is special interest to note the one in which both the fifth and sixth cervical nerve roots are composed of the dorsal scapular nerve. The existence of normal variations should be taken into account when determining the level and degree of branchial plexus injuries. 2. The nerve fascicules composing each peripheral nerve are most easily discerned at the cord level of the branchial plexus where there are no definite fiber exchanges between those nerve fascicules. These results would indicate that reconstructive nerve operations can be done successfully at the cord level or, at most, at the division level.