LAUSR

We previously reported an original study of ophthalmic artery (OA) origin variations, titled, “Persistent dorsal ophthalmic artery and ophthalmic artery arising from the middle meningeal artery diagnosed by MR angiography at 3 T,” in Surgical and Radiologic Anatomy (2013; 35:775–782) [6]. In this article, we concluded that the OA arising from the cavernous segment of the internal carotid artery (ICA) and entering the orbit via the superior orbital fissure (SOF) instead of the optic canal (OC) is persistent dorsal OA. According to Padget [4], the primitive ventral and dorsal OAs originate from the ICA at the levels of the anterior choroidal artery and posterior communicating artery, respectively. Caudal migration then occurs and forms adult OA. Because of the proximity of their origins and their similar courses, persistent primitive ventral and dorsal OAs cannot be distinguished in adult OA [2]. Intracavernous ICA-originating OA, which enters the orbit via the SOF, is now believed to be due to the persistence of the lateral branch of the primitive maxillary artery (PMA), not persistent dorsal OA, a notion that was based on a misreading of Padget’s work [1]. This type of OA originates from the inferolateral trunk (ILT) [7]. According to a microsurgical anatomic study [5], 8 of 100 OAs arose within the cavernous sinus, usually a few millimeters proximal to the dural ring, apparently located distal to the origin of the ILT. Furthermore, two of those eight OAs entered the floor of the OC through a bone foramen, forming double OCs. I recently experienced a patient in whom the OA arose from the cavernous ICA and entered the orbit via the OC (Fig. 1). Unfortunately, because the patient was not examined via computed tomography, whether or not the patient had double OCs is unclear. If double OCs are noted, the OA may be formed by persistence of a small branch of the PMA. In cases with a single OC, although the normal adult OA never goes down to the cavernous sinus [3], the OA may have originally been formed by excessive caudal migration of the primitive OA.