The premamillary artery—a microanatomical study

Abstract

The microanatomical parameters of the premamillary artery (PMA) for the different configurations of the posterior communicating artery-adult (aPComA), hypoplastic (hPComA) and foetal (fPComA) were assessed and analysed. A comparative study with relevance to the neurosurgical practice has been carried out. Red-coloured latex was injected in 35 human cadaver brains and a microanatomical dissection was performed. The area of emergence, the diameter, the length and the zone of penetration of the PMA were accessed. Seventy PComA were found and 96 PMA were identified. In more than 85% of the cases, the diameter of the PMA largely surpassed the diameter of the other perforating vessels. In the aPComA group, the PMA was a single branch in 72.4% of the cases with mean diameter of 0.52 mm and average length of 13.22 mm. PMA was found to originate from the middle third in 60.5%. For the hPComA group, in 66.7% of the cases, one PMA with mean diameter of 0.49 mm and average length 12.41 mm was found. In 60.9%, PMA originated from the middle third. For the fPComA group, in 50.0% of the cases, one PMA was found with mean diameter of 0.39 mm, average length of 12.42 mm. PMA was found to originate from the anterior third in 41.7% of the cases. Emergence of the PMA from the internal carotid artery and from the P2 segment of the posterior cerebral artery was also documented. For the aPComA and the hPComA groups, the typical PMA may be described as the largest and most constant perforating branch emerging from the anterior 2/3 of the PComA and reaching the paramedian perforate substance. The PMA of the fPComA generally conforms to these characteristics but it is usually thinner, frequently duplicated and with higher percent of atypical emergence. These anatomical peculiarities may facilitate the intraoperative identification and preservation of the PMA when dealing with vascular or neoplastic pathologies with parasellar or interpeduncular extension.