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Foramen Lacerum

foramen lacerum

The foramen lacerum is an irregular opening at the skull base between the apex of the petrous temporal bone, the basiocciput, and the basisphenoid. In life it is filled with fibrocartilage and is not truly patent; the internal carotid artery passes horizontally above it (through the carotid canal) but does not traverse it. The lesser petrosal nerve and small emissary veins pass through the foramen.

Region: Head & Skull

Clinical Relevance

Clinical Notes

The foramen lacerum is important surgically as the critical anatomical reference for the lacerum segment of the internal carotid artery in skull base surgery. Although the ICA does not truly traverse the foramen (it passes just above in the fibrocartilaginous roof of the foramen), the lacerum segment of the ICA can be inadvertently injured during infralabyrinthine or infratemporal fossa approaches. Nasopharyngeal carcinoma invades the skull base through the foramen lacerum in lateral spread.

Pathology

Common Injuries & Conditions

ICA Injury at Foramen Lacerum in Skull Base Surgery

Infralabyrinthine and infratemporal fossa approaches to the petroclival region must identify the lacerum segment of the ICA as it passes just above the fibrocartilage of the foramen lacerum; inadvertent drilling into this carotid segment causes catastrophic haemorrhage requiring immediate balloon occlusion test and potential sacrifice.