Background and Objectives: The labyrinthine artery (LA) is a small but surgically important vessel encountered during procedures involving the cerebellopontine angle (CPA). Variations in its number, origin, and relationship to the facial–vestibulocochlear nerve complex may increase the risk of vascular injury during CPA surgery. The aim of this cadaveric microdissection study was to evaluate the number, origin, and course of the LA within the CPA and to characterize its relationship to the anterior inferior cerebellar artery (AICA) and the facial–vestibulocochlear nerve complex. Materials and Methods: Microsurgical dissections were performed bilaterally in 45 formalin-fixed adult cadavers (90 CPAs) using an operating microscope and vascular injection. The number, origin, and course of the LA were analyzed together with its relationship to the AICA and the facial–vestibulocochlear nerve complex. Results: The LA was identified in all specimens. A single LA was observed in 57.8% of CPAs, whereas multiple LAs were identified in 42.2%. The artery most commonly originated from the AICA (65.6%), followed by a common trunk shared with the AICA (21.1%) and direct origin from the basilar artery (13.3%). In specimens with bifurcated AICAs forming double loops, multiple LAs frequently arose from both loops. Considerable variability was observed in the course of the LA relative to the facial–vestibulocochlear nerve complex, including superior, inferior, and interposed courses. Bilateral asymmetry was identified in 15.6% of cadavers. Conclusions: The LA demonstrates substantial anatomical variability within the CPA regarding its number, origin, and neurovascular relationships. Although the artery most commonly arises from the apex or medial aspect of the AICA loop, its subsequent course may vary considerably. Careful microsurgical inspection remains essential during CPA surgery, as the configuration of the AICA alone is insufficient to reliably predict the distal trajectory of the LA.
Jeican et al. (Mon,) studied this question.