Microsurgical anatomy of the posterior circulation
Pai Balaji S1, Varma Ravi G1, Kulkarni Raghavendra N2, Nirmala S1, Manjunath LC1, Rakshith S1
1 Department of Neurosurgery, MS Ramaiah Medical College, Bangalore – 560 085, India
2 Department of Anatomy, MS Ramaiah Medical College, Bangalore – 560 085, India
Context: The microsurgical anatomy of the posterior circulation is very complex and variable. Surgical approaches to this area are considered risky due to the presence of the various important blood vessels and neural structures. Aims: To document the microsurgical anatomy of the posterior circulation along with variations in the Indian population. Materials and Methods: The authors studied 25 cadaveric brain specimens. Microsurgical dissection was carried out from the vertebral arteries to the basilar artery and its branches, the basilar artery bifurcation, posterior cerebral artery and its various branches. Measurements of the outer diameters of the vertebral artery, basilar artery and posterior cerebral artery and their lengths were taken. Results: The mean diameter of the vertebral artery was 3.4 mm on the left and 2.9 mm on the right. The diameter of the basilar artery varied from 3-7 mm (mean of 4.3 mm). The length varied from 24-35 mm (mean of 24.9 mm). The basilar artery gave off paramedian and circumferential perforating arteries. The origin of the anterior inferior cerebellar artery (AICA) varied from 0-21 mm (mean 10.0 mm) from the vertebrobasilar junction. The diameter of the AICA varied from being hypoplastic i.e., Conclusions: The authors have documented the various anomalies as well as the differences of the anatomy in this area in the Indian population as compared to the Western literature.
Keywords: Basilar artery, microsurgical anatomy, posterior cerebral artery, posterior circulation, superior cerebellar artery
Neurol India 2007;55:31-41
The posterior circulation of the brain constitutes the vertebrobasilar system and its branches. The microsurgical anatomy of the posterior circulation is very complex and variable. Surgical approaches to this area are considered risky due to the presence of the various important blood vessels and neural structures. It is important for neurosurgeons to understand the microsurgical anatomy of the posterior circulation in order to treat pathologies in this area safely and confidently. Apart from the vascular pathologies like aneurysms and arteriovenous malformations, surgery in this area may be required for tumors, epilepsy surgery and for revascularization procedures.
Many authors have described the anatomy of the posterior circulation in detail. The works of Yasargil and Rhoton stand out due to their attention to detail and vivid description. There is a paucity of Indian literature in this regard. The aim and objective of the authors was to examine and document the microsurgical anatomy of the posterior circulation in a group of Indian cadavers.