Regional topography of the internal carotid artery

Abstract

We studied the extra cranial portion of the internal carotid artery and structures associated with it, which are vulnerable to iatrogenic injury during surgical approach to the neck region in 18 individuals. Distances from the origin of the artery to hypoglossal nerve and posterior belly of digastric muscle were measured. The mastoid process and the hyoid bone were also used as landmarks in locating the nerve and respective distances measured. Hypoglossal nerve and posterior belly of digastric muscle crossed the ICA at variable positions with a mean distance of 10.1mm and 17.9mm respectively from the common carotid bifurcation. From the mastoid process, the internal carotid artery ascends underneath the posterior belly of the digastric muscle a third the distance to the hyoid bone. The external carotid artery is located lateral to the internal carotid artery in 63.8% of the cases, posterior in 16.7% and anterior in 19.4%. The posterior belly of digastric muscle and its attachments are key landmarks in identifying the internal carotid artery and thus avoiding injury to vital neurovascular structures which may help structures, which may help, improve clinical outcomes during surgery.