Skeletal system · Head and neck
Foramen lacerum !
The foramen lacerum is a jagged gap in the skull base, filled by cartilage in life; the internal carotid artery passes over it.
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What it is
A jagged gap in the skull base, closed by cartilage in life.
What it does
The internal carotid passes over it.
Key facts
- Where
- Between the sphenoid, the petrous apex and the occipital
- Function
- Closed by cartilage in life; the internal carotid artery crosses its upper part; greater petrosal nerve passes to the pterygoid canal
Relations
- Contents
- Fibrocartilage plug; on it, the internal carotid artery with its sympathetic plexus and the greater and deep petrosal nerves; through it, small meningeal branches of the ascending pharyngeal artery and emissary veins
- Above
- Internal carotid artery entering the back of the cavernous sinus, with the trigeminal ganglion just lateral
- Below
- Roof of the nasopharynx, near the opening of the auditory tube and the pharyngeal recess
- In front
- Opening of the pterygoid canal at the root of the pterygoid process of the sphenoid bone
- Behind
- Apex of the petrous temporal bone, where the carotid canal opens
- Medial
- Body of the sphenoid and the basilar part of the occipital bone (clivus)
How to find it
It cannot be felt. On a dry skull it is the ragged gap between the petrous apex, the body and greater wing of the sphenoid and the basilar occipital, seen from inside the middle cranial fossa and from below.
On imaging
CT with bone windows shows the gap and erosion of its edges; MRI with contrast shows tumour or infection spreading through the cartilage toward the cavernous sinus or along the Vidian nerve.
Clinical notes
- In endoscopic skull base surgery the Vidian canal, followed backward, leads to the lacerum segment of the internal carotid artery, a key landmark for protecting it
- Chondrosarcoma typically arises near it, at the petroclival junction, while chordoma arises in the midline clivus
- Infection or tumour from the nasopharynx can reach the skull base through it
Development
It is the gap left where cartilage of the developing skull base does not turn into bone between the petrous apex and the sphenoid.
Test yourself
Think of the answer, then tap the question to see it.
Why is the foramen lacerum not a true passage in life?
Fibrocartilage fills its lower part; only small meningeal branches and emissary veins pierce it.
Which artery runs over the foramen lacerum?
The internal carotid artery, leaving the carotid canal and crossing the cartilage before turning up into the cavernous sinus.
Which nerve forms over the foramen lacerum?
The nerve of the pterygoid canal (Vidian nerve), from the greater and deep petrosal nerves.
Which tumour climbs through the foramen lacerum and classically presents with an abducens (VI) palsy?
Nasopharyngeal carcinoma, spreading toward the cavernous sinus.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- foramen lacerum TA2 459
- Official Spanish (DeCS)
- Agujero rasgado
- English (TA2)
- Foramen lacerum
Sources: Terminologia Anatomica (TA2); Anatomy, Head and Neck: Foramen Lacerum; Anatomy, Head and Neck, Skull Foramen.
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Representative model, for educational purposes only.