"C1: cervical segment (starts at carotid bifurcation)"
"C2: petrous segment (starts at carotid canal)"
"C3: lacerum segment (starts at posterior edge of foramen lacerum)"
"C4: cavernous segment (starts at the superior margin of petrolingual ligament)"
"C5: clinoid segment (starts at proximal dural ring / anterior clinoid process)"
"C6: ophthalmic (supraclinoid) segment (starts at distal dural ring / cavernous sinus roof)"
"C7: communicating (terminal) segment (starts just proximal to the origin of posterior communicating artery, ends at bifurcation into middle and anterior cerebral arteries)"
"C1: cervical segment (starts at carotid bifurcation)"
"C2: petrous segment (starts at carotid canal)"
"C3: lacerum segment (starts at posterior edge of foramen lacerum)"
"C4: cavernous segment (starts at the superior margin of petrolingual ligament)"
"C5: clinoid segment (starts at proximal dural ring / anterior clinoid process)"
"C6: ophthalmic (supraclinoid) segment (starts at distal dural ring / cavernous sinus roof)"
"C7: communicating (terminal) segment (starts just proximal to the origin of posterior communicating artery, ends at bifurcation into middle and anterior cerebral arteries)"
"There are a few other classification systems including those proposed by Fischer (1938), Gibo (1981), and Lasjaunias (1984) 2."