Applied anatomy for transfer of the spinal accessory nerve to the suprascapular nerve

Abstract

Objective Anatomical study of trapezius muscle innervations in order to find the best point for transfer of the spinal accessory nerve to the suprascapular nerve. Methods Observation of right and left trapezius muscle innervations in ten cadavers. Study the course and branches of accessory nerve with-in the trapezius muscle.Reseetion and cross-sectional biopsy of accessory and supraseapular nerves at different levels. Counting and comparing the number of nerve fibers at different levels in both nerves. Results The accessory nerve enters trapezius muscle within the deep fascia and run posterior just 2-3era above the clavicle. At the level of the midpoint of the spine of the scapula 3-4cm above and anterior, it unites with the cervical branch of the cervical plexus, then crosses medial to the spine of the scapula with straight course down to the lower trapezius. The number of nerve fibers in cross section at point A (just entering the muscle) was 1245± 46, in point B (just before union with cervical branch) was 830 ± 36 and in point C (posterior approach in-the anatomy is constant; Operation is simple and does not affect the upper trapezius muscle innervations. Also it gives us a full use of the cervical branch and shortens the nerve regeneration. Key words: Brachial plexus; Accessory nerve; Nerve transfer; Applied anatomy