The labyrinthine artery which is an end artery supplies the inner ear . This is a branch of anterior inferior cerebellar branch of internal carotid artery.
The inner ear blood supply is devoid of collateral and hence is highly vulnerable to ischemic effects.
The common cochlear branch of vestibule cochlear artery supplies the cochlea. The common cochlear artery gives rise to two branches :
Main cochlear artery that supplies the modiolus in the upper basal, middle and apical areas of the cochlea.
The cochlear ramus branch supplying about 1/4 of the basal coil and modiolus of cochlea.
Inside the modiolus the artery branches to form an external radiating arteriole and an internal radiating arteriole.
The external radiating arteriole travels within the inter scalar septum to reach the lateral wall of the cochlear coil. As soon as it reaches the lateral wall it gives raise to 4 vessel forming a capillary network. These vessels are :
i) Vessels of scala vestibule
ii) Vessels of spiral ligament
iii) Vessel scala tympani
iv) One branch contributing to the capillary network in the scala vestibule.
The internal radiating arteriole supplies the medial wall of the cochlear coil.
The arteries supplying the inner ear should pulsate less because pulsation are sufficient to cause excitation of the cochlea. In order to reduce the intensity of arterial pulsations the labyrinthine artery consists of many parallel arteries which ensure adequate blood supply to inner ear without intense pulsations.
VENOUS DRAINAGE :
The primary venous drainage of inner ear is via :
Vein of the cochlea
Vein of the vestibular aqueduct
The cochlea is primarily drained by anterior and posterior spiral veins.
The anterior spiral vein drain the supero-lateral
Scala vestibule and
osseous spiral lamina
The posterior spiral vein drains the inferior aspect of the cochlea
Scala media and
Ultimately the cochlear vein and the vein of the vestibular aqueduct drain via the inferior pestrosal sinus.