Azygos anterior cerebral artery
An azygos anterior cerebral artery is uncommon to rare variant of the circle of Willis where the two A1 segments of the anterior cerebral artery (ACA) join to form a single trunk. As a result, there is no anterior communicating artery. This organisation is similar to that seen in lower primates 2.
Epidemiology
They are present in approximately 0.4-1% of the population 1.
Pathology
Associations
It is associated with numerous abnormalities, including 1:
- dysgenesis of the corpus callosum
- lobar holoprosencephaly 3
- septo-optic dysplasia
- porencephalic cysts
- arteriovenous malformations (AVM)
Berry aneurysms are often seen at the eventual bifurcation of the single vessel, due to either altered haemodynamics or congenitally abnormal wall, or both. The reported incidence varies widely, from 13 to 71% 1.
As there is frequent hypoplasia of the ACOM and supply of the medial surface of the hemispheres by contralateral ACA branches, confirmation of an azygos ACA can be difficult on angiography 2. Cross compression views can be helpful.
Related articles
Neuroanatomy
- brain
-
cerebrum
-
cerebral hemisphere (telencephalon)
- cerebral lobes and gyri
- cerebral sulci and fissures (A-Z)
- calcarine fissure
- callosal sulcus
- central (Rolandic) sulcus
- cingulate sulcus
- collateral sulcus
- inferior frontal sulcus
- inferior temporal sulcus
- interhemispheric fissure
- lateral (Sylvian) sulcus
- marginal sulcus
- occipitotemporal sulcus
- olfactory sulcus
- parieto-occipital fissure
- posterior parolfactory sulcus
- precentral sulcus
- rhinal sulcus
- superior frontal sulcus
- superior temporal sulcus
- cortical histology
- white matter tracts
- deep grey matter
-
pituitary gland
- posterior pituitary and stalk (part of diencephalon)
- anterior pituitary
- pituitary gland blood supply
- embryology
- diencephalon
-
cerebral hemisphere (telencephalon)
-
brainstem
- midbrain (mesencephalon)
- pons (part of metencephalon)
- medulla oblongata (myelencephalon)
- white matter
- grey matter (non-cranial nerve)
-
cerebellum (part of metencephalon)
- vermis
- cerebellar hemisphere
- cerebellar peduncles
- cerebral meninges (meninx primitiva)
- CSF spaces
-
cranial nerves (mnemonic)
- olfactory nerve (CN I)
- optic nerve (CN II)
- oculomotor nerve (CN III)
- trochlear nerve (CN IV)
- trigeminal nerve (CN V) (mnemonic)
- abducens nerve (CN VI)
- facial nerve (CN VII) (segments mnemonic | branches mnemonic)
- vestibulocochlear nerve (CN VIII)
- glossopharyngeal nerve (CN IX)
- vagus nerve (CN X)
- spinal accessory nerve (CN XI)
- hypoglossal nerve (CN XII)
- functional neuroanatomy
- brain development
- cerebral vascular supply
- arteries
-
circle of Willis
- internal carotid artery (ICA)
- vertebral artery
-
normal variants
- intracranial arterial fenestration
- internal carotid artery (ICA)
- anterior cerebral artery (ACA)
- middle cerebral artery (MCA)
- posterior cerebral artery (PCA)
- basilar artery
- persistent carotid-vertebrobasilar artery anastomoses
-
circle of Willis
-
cerebral venous system
- dural venous sinuses
-
cerebral veins
-
superficial veins of the brain
- superior cerebral veins (superficial cerebral veins)
- inferior cerebral veins
- superficial middle cerebral vein
- superior anastomotic vein (of Trolard)
- inferior anastomotic vein (of Labbe)
- deep veins of the brain
-
superficial veins of the brain
- normal variants
- arteries
- glymphatic pathway
-
cerebrum
-
spinal cord
- gross anatomy
- white matter tracts
- anterolateral columns
- lateral columns
-
dorsal columns
- fasiculus gracilis
- fasiculus cuneatus (column of Burdach)
- gray matter
- nerve root
- spinal meninges and spaces
- functional anatomy
- spinal cord blood supply
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