Relations of the accessory nerve with the internal jugular vein: surgical implications in cervical lymph node clearances.

The position of the lateral branch of the accessory nerve in relation to the internal jugular vein is given variously by different authors. In surgery of the neck, and especially in conservative cervical lymph node clearances, the lateral branch of the accessory nerve is protected when it is situated lateral to the vein. However, when the nerve is medial to the vein there is a risk of damage to the internal jugular vein. A prospective preoperative study of 123 cervical lymph node clearances, as well as a dissection study of 5 fresh subjects, was carried out to determine the position of the lateral branch of the accessory nerve in relation to the internal jugular vein. The surgical study showed that the lateral branch of the nerve was anterior and lateral to the vein in 122 of the 123 clearances, while the cadaveric study found the nerve always anterior and lateral to the vein. Thus the risk of injuring the internal jugular vein during cervical lymph node clearances is very small. The differences observed by authors may be explained by collapse of the internal jugular vein observed during cadaveric dissections.