The sternomastoid branch of the occipital artery: A surgical landmark for the spinal accessory nerve in selective neck dissections

OBJECTIVE: To evaluate the anatomic relationship between the spinal accessory nerve (SAN) and the sternomastoid branch of the occipital artery (SBOA) and its utility as a surgical landmark during a selective neck dissection (SND). STUDY DESIGN AND SETTINGS: Consecutive patients undergoing SND for squamous cancer from October 1, 2004 to February 28, 2005 were enrolled in this study. During surgery the distance between the SBOA and the point of insertion of the SAN into the sternomastoid muscle (SMM) was measured. RESULTS: Twenty-four patients underwent 33 SND. The distance between the SBOA and SAN ranged between 1 and 11 mm, with a mean of 6.2 mm and a median of 6 mm. CONCLUSION: The relationship between these 2 structures has a range and constancy that is acceptable as a landmark. SIGNIFICANCE: This article presents a useful adjunct for location of the SAN in the anterior neck during SND.