Microsurgical anatomy of the posterior choroidal arteries.

In this study, we analysed the microanatomy of the medial and lateral posterior choroidal arteries, which supply vital central nervous system structures to the brainstem and choroids plexus. We traced the anatomical course of the medial and lateral posterior choroid arteries, their origin, diameter, number of branches, length, and anatomical variations. Twenty-six human unfixed brains were injected through the vertebral and carotid arteries with silicon rubber. Fifty-one out of a total of 129 vessels were medial posterior, and 78 were lateral posterior choroidal arteries. We divided the medial posterior choroidal artery into three segments: around the brainstem, quadrigeminal-pineal, and choroidal. The mean length of the medial posterior choroidal artery was 77.6 +/- 15 mm on the right side, and 77.1 +/- 15 mm on the left; the mean outer diameter observed was 0.8 +/- 0.5 mm on the right side, and 0.8 +/- 0.4 mm on the left. The number of branches arising from the medial posterior choroidal arteries averaged 25 +/- 9. In the lateral posterior group, the mean length observed was 49.5 +/- 26 mm on the right, and 58.0 +/- 23 mm on the left. There were instances of duplication and triplication of the lateral posterior choroidal vessels. The outer diameter averaged 0.72 mm on the right, and 0.6 mm on the left. The posterior choroidal arteries are clearly an important vascular component. A comprehensive knowledge of their anatomy will aid the neurosurgeon during surgery of the brainstem, pineal region, and third ventricle, and will limit complications resulting from injury to these arteries.