The anterior inferior cerebellar artery (AICA) is one of three pairs of

arteries An artery () is a blood vessel in humans and most other animals that takes oxygenated blood away from the heart in the systemic circulation to one or more parts of the body. Exceptions that carry deoxygenated blood are the pulmonary arteries in ...

that supplies blood to the

cerebellum The cerebellum (: cerebella or cerebellums; Latin for 'little brain') is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as it or eve ...

. It arises from the basilar artery on each side at the level of the junction between the medulla oblongata and the

pons The pons (from Latin , "bridge") is part of the brainstem that in humans and other mammals, lies inferior to the midbrain, superior to the medulla oblongata and anterior to the cerebellum. The pons is also called the pons Varolii ("bridge of ...

in the

brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is conti ...

. It has a variable course, passing backward to be distributed to the anterior part of the undersurface of the cerebellum, anastomosing with both the posterior inferior cerebellar (PICA) branch of the

vertebral artery The vertebral arteries are major artery, arteries of the neck. Typically, the vertebral arteries originate from the subclavian arteries. Each vessel courses superiorly along each side of the neck, merging within the skull to form the single, m ...

and the

superior cerebellar artery The superior cerebellar artery (SCA) is an artery of the head. It arises near the end of the basilar artery. It is a branch of the basilar artery. It supplies parts of the cerebellum, the midbrain, and other nearby structures. It is the cause of t ...

. It also gives off the internal auditory or labyrinthine artery in most cases; however, the labyrinthine artery can less commonly emerge as a branch of the basilar artery. The amount of tissue receiving blood supply from the AICA is variable, depending upon whether the PICA is more or less dominant, but usually includes the anteroinferior surface of the

, the flocculus, middle cerebellar peduncle and inferolateral portion of the pons.

Clinical significance

Occlusion of AICA is considered rare, but generally results in a lateral pontine syndrome, also known as AICA syndrome. The symptoms include sudden onset of

vertigo Vertigo is a condition in which a person has the sensation that they are moving, or that objects around them are moving, when they are not. Often it feels like a spinning or swaying movement. It may be associated with nausea, vomiting, perspira ...

, vomiting, nystagmus,

dysarthria Dysarthria is a speech sound disorder resulting from neurological injury of the motor component of the motor–speech system and is characterized by poor articulation of phonemes. It is a condition in which problems effectively occur with the ...

, falling to the side of the lesion (due to damage to

vestibular nuclei The vestibular nuclei (VN) are the cranial nuclei for the vestibular nerve located in the brainstem. In Terminologia Anatomica, they are grouped in both the pons and the medulla in the brainstem The brainstem (or brain stem) is the poste ...

), and a variety of same-side features including hemiataxia, loss of all types of sensation of the face (due to damage to the principal sensory trigeminal nucleus), facial paralysis (due to damage to the facial nucleus), and hearing loss and

tinnitus Tinnitus is a condition when a person hears a ringing sound or a different variety of sound when no corresponding external sound is present and other people cannot hear it. Nearly everyone experiences faint "normal tinnitus" in a completely ...

(due to damage to the cochlear nuclei). Facial nucleus damage and its resulting paralysis are specific to AICA lesions, and may be the most distinct clinical identifier of this type of stroke before a

CT scan A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or ...

or MRI may be obtained. Vertigo may sometimes present as an isolated symptom several weeks or months before acute ischemia and cerebral infarction occurs, probably with the meaning of transient ischemia of the inner ear or the vestibular nerve. There is also loss of pain and temperature sensation from the contralateral (opposite-side) limbs and trunk, which can lead to diagnostic confusion with lateral medullary syndrome, which also gives rise to "crossed" neurological signs but does not normally cause cochlear symptoms, severe facial palsy or broad facial sensory loss.

References

External links

* * http://neuroangio.org/anatomy-and-variants/aica/ * {{Authority control Arteries of the head and neck