Anterior inferior cerebellar artery | |
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![]() Diagram of the arterial circulation at the base of the brain (inferior view). AICA is labeled at lower right. | |
Details | |
Source | Basilar artery |
Branches | Labyrinthine artery |
Vein | Inferior cerebellar veins |
Supplies | Anteroinferior surface of the cerebellum, the flocculus, middle cerebellar peduncle and inferolateral portion of the pons. |
Identifiers | |
Latin | arteria cerebelli inferior anterior |
TA98 | A12.2.08.019 |
TA2 | 4550 |
FMA | 50544 |
Anatomical terminology |
The anterior inferior cerebellar artery (AICA) is one of three pairs of arteries that supplies blood to the cerebellum.
It arises from the basilar artery on each side at the level of the junction between the medulla oblongata and the pons in the brainstem. 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 and the superior cerebellar artery.
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 cerebellum, the flocculus, middle cerebellar peduncle and inferolateral portion of the pons. [1]
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, vomiting, nystagmus, dysarthria, falling to the side of the lesion (due to damage to vestibular nuclei), 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 (due to damage to the cochlear nuclei). [2] [3] [4] 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 or MRI may be obtained. [5]
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. [6]
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. [7]
The cerebellum 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 even larger. In humans, the cerebellum plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language as well as emotional control such as regulating fear and pleasure responses, but its movement-related functions are the most solidly established. The human cerebellum does not initiate movement, but contributes to coordination, precision, and accurate timing: it receives input from sensory systems of the spinal cord and from other parts of the brain, and integrates these inputs to fine-tune motor activity. Cerebellar damage produces disorders in fine movement, equilibrium, posture, and motor learning in humans.
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The pons 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 brainstem is the stalk-like part of the brain that interconnects the cerebrum and diencephalon with the spinal cord. In the human brain, the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is continuous with the thalamus of the diencephalon through the tentorial notch.
The vestibulocochlear nerve or auditory vestibular nerve, also known as the eighth cranial nerve, cranial nerve VIII, or simply CN VIII, is a cranial nerve that transmits sound and equilibrium (balance) information from the inner ear to the brain. Through olivocochlear fibers, it also transmits motor and modulatory information from the superior olivary complex in the brainstem to the cochlea.
Lateral medullary syndrome is a neurological disorder causing a range of symptoms due to ischemia in the lateral part of the medulla oblongata in the brainstem. The ischemia is a result of a blockage most commonly in the vertebral artery or the posterior inferior cerebellar artery. Lateral medullary syndrome is also called Wallenberg's syndrome, posterior inferior cerebellar artery (PICA) syndrome and vertebral artery syndrome.
Medial medullary syndrome, also known as inferior alternating syndrome, hypoglossal alternating hemiplegia, lower alternating hemiplegia, or Dejerine syndrome, is a type of alternating hemiplegia characterized by a set of clinical features resulting from occlusion of the anterior spinal artery. This results in the infarction of medial part of the medulla oblongata.
The basilar artery is one of the arteries that supplies the brain with oxygen-rich blood.
The posterior cerebral artery (PCA) is one of a pair of cerebral arteries that supply oxygenated blood to the occipital lobe, part of the back of the human brain. The two arteries originate from the distal end of the basilar artery, where it bifurcates into the left and right posterior cerebral arteries. These anastomose with the middle cerebral arteries and internal carotid arteries via the posterior communicating arteries.
Vertebrobasilar insufficiency (VBI) describes a temporary set of symptoms due to decreased blood flow (ischemia) in the posterior circulation of the brain. The posterior circulation supplies the medulla, pons, midbrain, cerebellum and supplies the posterior cerebellar artery to the thalamus and occipital cortex. As a result, symptoms vary widely depending which brain region is predominantly affected.
The posterior inferior cerebellar artery (PICA) is the largest branch of the vertebral artery. It is one of the three main arteries that supply blood to the cerebellum, a part of the brain. Blockage of the posterior inferior cerebellar artery can result in a type of stroke called lateral medullary syndrome.
The cerebellopontine angle (CPA) is located between the cerebellum and the pons. The cerebellopontine angle is the site of the cerebellopontine angle cistern.
The internal auditory meatus is a canal within the petrous part of the temporal bone of the skull between the posterior cranial fossa and the inner ear.
The labyrinthine artery is a branch of either the anterior inferior cerebellar artery or the basilar artery. It accompanies the vestibulocochlear nerve through the internal acoustic meatus. It supplies blood to the internal ear.
The middle cerebellar peduncle is a paired structure of the brain. It connects the pons to the cerebellum, with fibres originating from the pontine nucleus and travelling to the opposite hemisphere of the cerebellar cortex. It is supplied by the anterior inferior cerebellar artery (AICA) and branches from the basilar artery. It conveys information from the cerebrum and the pons to the cerebellum.
The basilar part of pons, also known as basis pontis, is the ventral part of the pons; the dorsal part is known as the pontine tegmentum.
The medial vestibular nucleus is one of the vestibular nuclei. It is located in the medulla oblongata.
Benedikt syndrome, also called Benedikt's syndrome or paramedian midbrain syndrome, is a rare type of posterior circulation stroke of the brain, with a range of neurological symptoms affecting the midbrain, cerebellum and other related structures.
The anatomy of the cerebellum can be viewed at three levels. At the level of gross anatomy, the cerebellum consists of a tightly folded and crumpled layer of cortex, with white matter underneath, several deep nuclei embedded in the white matter, and a fluid-filled ventricle in the middle. At the intermediate level, the cerebellum and its auxiliary structures can be broken down into several hundred or thousand independently functioning modules or compartments known as microzones. At the microscopic level, each module consists of the same small set of neuronal elements, laid out with a highly stereotyped geometry.
This article incorporates text in the public domain from page 580 of the 20th edition of Gray's Anatomy (1918)