Dual spinal accessory nerve: an anatomical anomaly during neck dissection.

The spinal accessory nerve (SAN) is an important cranial nerve encountered during neck dissection. Preservation of this nerve from iatrogenic damage is crucial to avoid debilitating sequalae, which can be made challenging due to variation of its anatomical course. In this case report, we present a patient who underwent supraomohyoid neck dissection, where a rare variation of a dual SAN, traversing the internal jugular vein midway, was encountered. In this case report, we study this anatomical finding, which is undoubtedly a valuable addition to the existing knowledge of the SAN. Ultimately, allowing surgeons to develop further awareness of the variations of the SAN and contributing to favourable postoperative outcomes.