Aberrant courses of the occipital artery

The occipital artery (OA), typically arising from the external carotid artery (ECA), usually courses deep to the posterior belly of the digastric muscle as it ascends toward the skull base. While variations in the height of origin from the ECA are known, aberrant courses of the OA have not been previously documented.

This study presents a four-case series identified through retrospective analysis of archived CT angiograms involving three female and one male patient, aged between 57 and 66.

In two cases, the OA was observed to pass deep to the internal jugular vein instead of its usual superficial trajectory; these variants were located on the left side. In the remaining two cases, the OA demonstrated aberrant retromandibular courses deep within the parotid glands. One of these cases revealed bilateral retromandibular segments of the OA, while the other exhibited a common occipitoauricular trunk originating from the right superficial temporal artery within the parotid space, which subsequently divided into the posterior auricular artery and the OA.

These previously unreported anatomical variations are clinically significant and should be considered during surgical or interventional procedures involving the parotid region.