Intradural anastomoses between the accessory nerve and the posterior roots of cervical nerves: Their clinical significance

Abstract

This study was performed to identify the anastomoses between the accessory nerve and the posterior roots of cervical nerves below the level of C1 segment, and to evaluate their clinical significance. One hundred spinal cord sides of Koreans were studied under the surgical microscope. In order to trace the posterior root of a cervical nerve after anastomosis with the accessory nerve, or the bridging fibers between the accessory nerve and the cervical posterior roots, the accessory nerves with the posterior roots and the bridging fibers were stained with osmium tetroxide. The anastomosis was classified into five types, according to whether the accessory nerve and the cervical posterior root crossed each other, and also according to the site of the bridging fiber between them. The bridging fibers in the most common type of anastomoses were observed to connect the posterior roots of a cervical nerve with the spinal rootlet of the accessory nerve. The possibility that the motor fibers of accessory nerve from the spinal cord may innervate the trapezius muscle through the cervical nerve, was discussed.

A Unique Case of Intradural Communicating Branches between the Accessory Nerve and the Dorsal Roots of the Cervical Spinal Nerves

“…2a-e). The connection observed on the right in the present case was similar to the type C of Oh et al 3 However, they described the communication of the accessory nerve to be present at the C2 dorsal rootlet in 87% of the dissections; in the present case it was observed at C4. The connection observed in the present case on the left did not fit into the classification of Oh et al, 3 nor was it reported earlier in the literature.…”

“…The connection observed on the right in the present case was similar to the type C of Oh et al 3 However, they described the communication of the accessory nerve to be present at the C2 dorsal rootlet in 87% of the dissections; in the present case it was observed at C4. The connection observed in the present case on the left did not fit into the classification of Oh et al, 3 nor was it reported earlier in the literature. 4 The anatomical explanation that the accessory nerve spinal motor fibers connect with the cervical dorsal root sensory fibers may be that the peripheral processes of the neurons in the cervical dorsal root ganglia may reach the spinal accessory nerve rootlets via communicating branches (►Fig.…”

“…2 The connections of the spinal accessory nerve with the dorsal roots of the cervical spinal nerves have been described in cadaver studies. 3,4 In the present case, we report the case of a connection between the spinal accessory nerve rootlets and the dorsal root of the cervical spinal nerve that has not been documented in the literature and we further discuss the functional anatomy of these connections.…”

Intradural communication between dorsal rootlets of spinal nerves: their clinical significance

“…Early studies supply extensive morphometric data on the size, number, diameter, and the myelinated properties of fibers forming the dorsal and ventral rootlets of spinal nerves in humans [24]. Further, the communications of the cervical dorsal rootlets with the spinal accessory nerve have been described in detail [3,14,16,22,24]. However, a few anatomical studies demonstrate the communications between cervical dorsal rootlets [23,30].…”

Disorders of the lower cranial nerves

“…[ 7 ] Anastomoses between the spinal component of the accessory nerve and the dorsal roots of the cervical nerves exist below level C1. [ 8 9 ]…”