Basal skull fracture
Overview
A basal (skull‑base) fracture involves the inferior cranial vault (anterior, middle or posterior cranial fossae).
Because multiple cranial nerves and major vessels pass through foramina in the cranial base, these fractures carry an increased risk of cranial‑nerve injury, vascular injury, cerebrospinal fluid (CSF) leak and intracranial infection.
In the emergency department the recognition of specific clinical features is critical: their presence mandates urgent imaging and often specialist input (NICE NG232).
Anatomy and mechanism - why basal fractures matter
The cranial base contains the cribriform plate, optic canal, carotid canal, internal acoustic meatus, jugular foramen and foramen magnum. Fractures can therefore:
- Tear dura and produce CSF rhinorrhoea or otorrhoea.
- Entrap or transect cranial nerves causing anosmia, optic impairment, facial palsy, hearing/vestibular loss, or lower cranial nerve deficits.
- Lacerate or dissect vessels (for example internal carotid artery or cavernous sinus), causing delayed stroke, pseudoaneurysm or catastrophic haemorrhage.
- Provide a portal for infection to the subarachnoid space, increasing meningitis risk.
- Create pneumocephalus; positive‑pressure ventilation may precipitate tension physiology.