Basal subarachnoid haemorrhages (BSAHs) could be traumatic and non-traumatic. The main cause for traumatic BSAH is rupture of arterial wall whilst theprimary reason for non-traumatic BSAH is the inherentand/ oracquired pathological changes of arterial wall. The current classifications do not meet the requirements of simultaneous accounting of morphological and etiological signs of BSAHs. The difficulties arising within etiological interpretation of BSAH in clinical and forensic practices are discussed.

Background: Basal subarachnoid hemorrhage (SAH) caused by rupture of intracranial aneurysms usually has non-traumatic etiology. However, head injury shortly before death can start legal case, even if aneurysm was found. In such cases, forensic pathologists have to decide on the cause of the rupture and the role of the injury. Case presentation: The article presents a rare case from forensic practice: 43 years old male dies after a head blunt trauma. The death was caused by basal SAH, which was caused by a microaneurysm rapture of the left posterior cerebral artery. The autopsy revealed external damages on the face and focal hemorrhages in soft tissues of the head and back. A detailed analysis of the morphological findings, clinical picture and circumstances was performed. The results showed that it was non-traumatic basal SAH. The cause of aneurism rupture was intracranial hypertension increased by vomiting and unusual body position shortly before the death. Conclusion: Available published articles were studied on the causes of ruptures of pathological cerebral arteries and forensic interpretation in controversial cases. Results suggest that current recommendations should be revised. The hypothesis of the most significant sign indicating unnatural death (localization of the damage in the projection of the brain base) could not be confirmed.