Anatomical variations of the spinal accessory nerve and its relevance to level IIb lymph nodes

Abstract

Our results may help to minimize the incidence of injuring the SAN in the upper neck during ND. Neck level IIb would contain more LNs if the course of the nerve leans toward the ventral side.

Four cases of spinal accessory nerve passing through the fenestrated internal jugular vein

“…This type of architecture is classified as fenestration, since it features window-like openings. According to this classification, 15 cases of fenestration of the IJV, similar to the present case, have been reported in the English literature [5][6][7]. Interestingly, the SAN passes through the duplicated IJV in almost all cases.…”

“…In the most recent prospective study, Lee et al [5] encountered this anomaly in 5 (2.8%) cases during 181 NDs. In our study, the clinical incidence was 4 (2.1%) per 192 unilateral NDs.…”

“…Only a few previous studies have reported on the incidence of this anomaly. Hollinshead reported identifying 3.2% during cadaver dissection, and Prades et al reported 4 (0.4%) instances of this anomaly per 1,000 unilateral NDs [3,5].…”

An anatomical Variation of the Lesser Occipital Nerve in the “Carefree part” of the Posterior Triangle

“…In all the reported cases, SAN received these contributions deep in the SM [8,9]. For the first time, we are reporting the presence of communicating branch in the posterior triangle.…”

“…Most of these contributions come from the C2, both C2 and C3, or C3 spinal nerves [8]. In a study, Lee et al, [9] found the contributions from C2 in 53.1% cases; from C2 and C3 in 38.1% cases and anatomy Section…”