| Segment | Description | Notes |
| C1 (Cervical) | CCA bifurcation to entrance of carotid canal | |
| C2 (Petrous) | …to posterior edge of formaen lacerum | |
| C3 (Lacerum) | …to superior margin of petrolingual ligament | |
| C4 (Cavernous) | …to proximal dural ring (anterior clinoid process) | |
| C5 (Clinoid) | …to distal dural ring
(cavernous sinus roof) |
|
| C6 (Ophthalmic) | … to just proximal to the origin of PComm | |
| C7 (Communicating) | … to ICA bifurcation |
References:
Bouthillier, A., et al. (1996). “Segments of the internal carotid artery: a new classification.” Neurosurgery 38(3): 425 – 432.