title: Variations in the anatomy of the vertebral artery cervical loop segment - a potential predisposing factor for traumatic basal subarachnoid hemorrhage?
abstract: Fatal traumatic basal subarachnoid hemorrhage (TBSAH) is a characteristic forensic pathological entity, the investigation of which requires special techniques. In Liverpool, post-mortem room angiography is undertaken, followed by complete removal of the vertebral arteries and histological examination. It has been observed that the arterial anatomy can be highly variable, particularly the length and course of the loop segments located between the C2 vertebra and the dura. In a number of cases of TBSAH the loop segments of torn vessels have appeared relatively short. Having observed this phenomenon subjectively in our case work, a radiological study was undertaken with the aim of quantifying vertebral artery loop anatomy variation in a 'normal' population. Multiphase post-mortem computed tomography angiography (MPMCTA) scans of 98 subjects were reviewed and the lengths of the different portions of the loop segments (foramen magnum to the upper border of C1, between C1 and C2, and the bony foramina themselves) of each vertebral artery were measured using semi-automated vessel analysis software. The measurements obtained provide objective evidence of marked anatomical variation, with some loop segments more than twice the length of others. These results are important because a short vertebral artery loop segment might be a significant factor in predisposing an individual to TBSAH following a blow to the head or neck.
authors.affiliation: Forensic Pathology Unit, Department of Pathology, The Royal Liverpool University Hospital, 5th Floor Duncan Building Prescot Street, Liverpool, L7 8XP, UK. jonathan.medcalf@nhs.net.
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Medcalf
authors.affiliation: Forensic Pathology Unit, Department of Pathology, The Royal Liverpool University Hospital, 5th Floor Duncan Building Prescot Street, Liverpool, L7 8XP, UK.
authors.forename: C
authors.initials: C
authors.lastname: Paul Johnson
authors.affiliation: Department of Medical Physics and Clinical Engineering, Royal Liverpool University Hospital, Liverpool, UK.
authors.forename: Azzam
authors.initials: A
authors.lastname: Taktak
authors.affiliation: CURML, University Center of Legal Medicine, Chemin de la Vulliette 4, 1000, Lausanne 25, Switzerland.
authors.forename: Silke
authors.initials: S
authors.lastname: Grabherr
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000072226:Computed Tomography Angiography; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D020206:Subarachnoid Hemorrhage, Traumatic / Q000209:etiology; D014711:Vertebral Artery / Q000002:abnormalities* / Q000000981:diagnostic imaging*; D055815:Young Adult
keywords: Angiography; Post-mortem computed tomography; Traumatic basal subarachnoid hemorrhage; Vertebral artery