Related Subjects:
|Medulla Oblongata
|Midbrain
|Pons
|Caudate Nucleus
|Putamen and Globus Pallidus
|Cerebral Cortex
|Internal Capsule
|Cavernous sinus
|Basal Ganglia
|Brainstem Anatomy
|Thalamic Anatomy
|Caudate Nucleus
🧠 The cavernous sinus is a large, paired venous sinus located on either side of the pituitary gland in the middle cranial fossa.
It is a key venous crossroads draining blood from the brain, orbit, and face - and a critical structure due to the nerves and artery that pass through it.
🔬Anatomy
- Location: Lies bilaterally, lateral to the sella turcica, extending from the superior orbital fissure (anterior) to the petrous apex of the temporal bone (posterior).
- Structure: Trabeculated venous plexus with thin walls, making it vulnerable to spread of infection or tumour.
- Connections:
- Receives venous blood from 👁️ superior & inferior ophthalmic veins, superficial middle cerebral vein, and sphenoparietal sinus.
- Drains via the superior & inferior petrosal sinuses into the internal jugular vein.
- Communicates with the pterygoid venous plexus and facial veins (basis of “danger triangle” of face).
Contents
- Within the sinus:
- Internal carotid artery (surrounded by sympathetic carotid plexus).
- Cranial nerve VI (abducens) runs beside the ICA → most vulnerable to compression.
- In lateral wall of sinus:
- CN III (oculomotor)
- CN IV (trochlear)
- CN V1 (ophthalmic division of trigeminal)
- CN V2 (maxillary division of trigeminal)
- Relations: Medial to temporal lobe, lateral to pituitary gland, inferior to optic chiasm.
Clinical Significance
- Cavernous Sinus Thrombosis:
- Source: Infections from the danger triangle of the face (via facial → ophthalmic veins).
- Features: Severe headache, fever, chemosis, proptosis, ophthalmoplegia (III, IV, VI palsies), ↓ corneal reflex (V1 involvement), visual loss.
- Emergency requiring IV antibiotics, anticoagulation, and often neurosurgical input.
- Tumour Invasion: Pituitary adenomas, meningiomas, nasopharyngeal tumours may extend into the cavernous sinus → painful ophthalmoplegia, facial sensory loss.
- Aneurysm of ICA: May compress cranial nerves → diplopia, ophthalmoplegia.
- Key Clinical Pearl: Early CN VI palsy (failure of lateral gaze) is often the first sign of cavernous sinus pathology 👀.
