The arterial circulation of the inner ear (Fig. 12-4 (Figure Not Available) ) is completely supplied by the labyrinthine artery. The labyrinthine artery has a variable origin. Most often it is a branch of the anterior inferior cerebellar artery (AICA), but occasionally, it is a direct branch of the basilar artery. As it enters the inner ear, it divides into the anterior vestibular artery and the common cochlear artery. The anterior vestibular artery supplies the vestibular nerve, most of the utricle, and the ampullae of the lateral and anterior semicircular canals. The common cochlear artery divides into a main branch, the main cochlear artery, and the vestibulocochlear artery. The main cochlear artery supplies the cochlea. The vestibulocochlear artery supplies part of the cochlea, ampulla of the posterior semicircular canal, and inferior part of the saccule. The labyrinth has no collateral anastomotic network and is highly susceptible to ischemia. Only 15 seconds of selective blood flow cessation is needed to abolish auditory nerve excitability. [5
The vertebral-basilar arterial system provides the vascular supply for both the peripheral and central auditory vestibular system. The posterior inferior cerebellar arteries (PICA) branch off the vertebral arteries. They supply the surface of the inferior portions of the cerebellar hemispheres, as well as the dorsolateral medulla, which includes the inferior aspects of the vestibular nuclear complex. The basilar artery is the principal artery of the pons. The basilar artery supplies central vestibular structures via perforator branches, which penetrate the medial pons, short circumferential branches, which supply the anterolateral aspect of the pons, and long circumferential branches, which supply the dorsolateral pons. The anterior-inferior cerebellar artery (AICA) supplies both the peripheral vestibular system, via the labyrinthine artery, as well as the ventrolateral cerebellum and the lateral tegmentum of the lower two thirds of the pons. Central auditory cortex is mainly supplied by the middle cerebral artery.
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