Normal Variants
It is important to have a strong fund of knowledge of both normal cerebral
vascular anatomy and normal variants in order to distinguish these from
collateral pathways. Common and uncommon normal variants include:
Primitive connections between internal carotid and
posterior fossa
Trigeminal artery
Hypoglossal artery
Stapedial
artery
Internal carotid artery
Origin
of occipital artery
Cervical internal carotid loops or coils
Recurrent
artery of Heubner/medial lenticulostriate arteries
Anterior
falx artery enlargement
Origin
of ascending pharyngeal artery
Aberrant petrous portion
Cavernous
ophthalmic artery origin
Origin
of posterior cerebral artery, "fetal
origin"
External carotid artery
Ophthalmic
origin from middle meningeal
Origin of posterior
meningeal artery
Circle of Willis
Complete
Circle of Willis
Basilar artery
Multiple superior cerebellar arteries
Tortuous course of basilar artery
Vertebral artery
Isolated posterior inferior
cerebellar artery
Inferior thyroid artery origin
Absent vertebral artery