Anatomic Topographical Relationship of the Intraspinal Accessory Root to the Upper Cervical Roots and to the Vessels of the Cranial Cervical Region

Abstract

The object of this investigation was to provide a statistical interpretation of macroscopic anatomic findings in the cranial cervical region, which is very rich in variation. In this way rare nervous and vascular variations could be related statistically. The first cervical posterior root demonstrated the most striking variations, which, according to anlage and connection with the accessory nerve, was divided into four anlage types of formation. In this way it was shown that in only 23% of the cases, no posterior C-1 root had been formed. It was further demonstrable that in at least part of the cases the accessory nerve was sensibly mixed with the first posterior root. Furthermore, nervous structures and peculiarities in the vessels were investigated. Special courses taken by the posterior inferior cerebellar artery, in addition to those already known, were statistically interpreted. Nervous as well as vascular contact and courses were analyzed, especially in relation to their topography to the accessory nerve, in order to provide clinicians with possibilities for explanations of irritations or compressions of this cranial nerve.

Variations of the accessory nerve: anatomical study including previously undocumented findings-expanding our misunderstanding of this nerve

“…9,10 Intradural communication between the first cervical nerve rootlets/root and the accessory nerve have been described. [11][12][13] Surprisingly, the anastomosis between the accessory nerve and the posterior C1 nerve rootlets/root has been reported to be more frequent in patients with spasmodic torticollis. 14 Figure 2.…”

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].…”

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

“…9 Following surgery some patients had a severe "shoulder syndrome" due to the accessory nerve dissection. 8,10 The difference in the postsurgical outcome can be due to the variable connections of the accessory nerve with the dorsal roots of cervical nerves. Further, dissection of the accessory nerve for various surgical purposes may result in loss of proprioceptive sensations from the trapezius and the sternocleidomastoid muscles in the case of accessory-cervical dorsal root communications.…”