The Lateral Perforating Branches of the Anterior and Middle Cerebral Arteries

T IS well known that aneurysms occur at the site of branching of the large vessels at the base of the brain. Two relatively common sites are in the region of the anterior communicating vessel and the site of branching of the main stem of the middle cerebral artery. Unfortunately, these sites frequently are the location of important lateral perforating vessels which irrigate large cell masses enclosing bands of traversing axone fiber bundles, namely the internal capsule. Frequently, the small perforating vessels are not well visualized at operation and damage to them will, at times, produce severe neurological deficits. These vessels can be well demonstrated in autopsy specimens of fresh brain by gross dissection and roentgenography, after injection of radiopaque substances2 In order to define the precise location of the lateral perforating vessels, it was thought helpful to present a brief overall survey of certain vascular relationships to the brain.