A Rare Positional Variant of the Accessory Nerve and the Internal Jugular Vein in the Neck

Owing to the regularity of anatomical structural relations, orientation on landmarks has a prominent didactic role in neck surgery. All surgeons working in the neck are confronted with the challenge of dissecting major cranial nerves and vessels, above all the accessory nerve (N. XI) and the internal jugular vein (IJV), in close proximity to other structures. According to the literature, N. XI usually runs lateral (in ca. 70–96% of cases) or medial (3–30%) to the IJV and is thus an important structure for orientation in the neck. We describe here an extremely rare positional variant (<1% of cases) in which N.XI runs through an aperture in the IJV (Figure). Various theories on the embryological genesis of this variant have been advanced, with vascular, neural, and bony origins all being discussed. Duplication of the vein seems to provide the best explanation for the anomalous position of N. XI. This case serves to emphasize the importance of also taking this rare anomaly into account to avoid accidental injury of nerves and vessels.

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Dr. med. Christian Jacobi, Prof. Dr. med. Ulrich Harréus, Stadtklinik Bad Tölz, HNO, [e-mail]

Conflict of interest statement: The authors declare that no conflict of interest exists.

Translated from the original German by David Roseveare.

Cite this as: Jacobi C, Harréus U: A rare positional variant of the accessory nerve and the internal jugular vein in the neck. Dtsch Arztebl Int 2022; 119: 490a. DOI: 10.3238/arztebl.m2022.0097