Superior orbital fissure
Exit foramen · CN III CN IV CN V1 CN VI
The gap between the greater and lesser wings of the sphenoid that links the cavernous sinus to the orbit. III, VI and the nasociliary nerve pass through the common tendinous ring into the muscle cone; IV and the frontal and lacrimal branches of V1 pass above the ring with the superior ophthalmic vein. The same nerves, with V2 and the internal carotid artery, occupy the cavernous sinus immediately behind.
Traced from the start
Detail
- Transmits
- Oculomotor (superior and inferior divisions), trochlear, ophthalmic division of trigeminal (lacrimal, frontal, nasociliary), abducens, superior ophthalmic vein, sympathetic fibres to the orbit
- Inside the tendinous ring
- III (both divisions), VI, nasociliary nerve and the sympathetic root of the ciliary ganglion
- Outside the ring
- IV, frontal and lacrimal nerves, superior ophthalmic vein
- Cavernous sinus
- Lateral wall from above down: III, IV, V1, V2; free within the sinus: VI and the internal carotid artery
When it goes wrong
Superior orbital fissure syndrome from a lateral orbital wall fracture, tumour or inflammation (Tolosa–Hunt)
Complete painful ophthalmoplegia with ptosis, a fixed dilated pupil and numbness of the forehead and cornea, with vision preserved; visual loss added means the optic canal is involved (orbital apex syndrome)
Cavernous sinus thrombosis spreading from a mid-facial boil, dental or sphenoid sinus infection through the valveless ophthalmic veins
Fever, proptosis, chemosis and painful ophthalmoplegia beginning with VI, then III and IV, with V1 and V2 sensory loss; it becomes bilateral within days through the intercavernous sinuses
Internal carotid aneurysm or pituitary tumour invading the cavernous sinus
Painless progressive palsies of III, IV and VI with V1 and V2 numbness, sometimes with a Horner syndrome from the carotid sympathetic plexus
Practise this structure
1 question in the bank tagged Extraocular Muscles.