Fatal subarachnoid hemorrhage caused by rupture of variant anterior communicating artery: a case report and literature review.

Fatal subarachnoid hemorrhage (SAH) caused by anterior communicating artery (ACoA) rupture is a rare event in medicolegal practice. Anatomical variations of the ACoA tend to make its anatomical structure, and as a result, blood flow through it, more complicated, which may increase hemodynamic stress and cause weak spots in the affected blood vessels. Variant ACoAs are prone to rupture in the event of a blunt-force trauma. Here, we report a fatal case of SAH caused by the rupture of a variant ACoA when the victim's head was struck from behind, causing the head to rotate and the victim to fall forward onto the ground. A medicolegal autopsy revealed diffuse basal SAH and ACoA duplication. The smaller of the two variant ACoA branches had ruptured near its junction with the right anterior cerebral artery. No basal aneurysms or other fatal diseases or injuries were found. This case highlights the significance of anatomical variation in forensic pathology.