The path of the internal carotid artery

The contents of the intracranial cavity are largely supplied by the circle of Willis anastomosis. The internal carotid arteries and vertebral arteries supply the anterior and posterior circulatory components of the anastomosis respectively. This article will focus on the internal carotid artery (ICA) and it's complex journey from the extra-cranial region to the intracranial space.

Down and in or down and out?

Warning: Read when sober and after sufficient ingestion of caffeine! The action of the extraocular muscles often causes considerable confusion, this is because people get confused between the anatomical action (where the action of each muscle is considered independently) and how the muscle is clinically tested (where one often has to take into account more than one muscle moving the eye).