The cavernous sinus - contents and surrounding structures (dave's notes) Flashcards
What is found within the cavernous sinus?
The internal carotid artery, and VI abducens
What is embedded in the lateral wall of the cavernous sinus?
3rd and 4th CNs, and O and M branches of the 5th cranial nerve
How does the internal carotid artery enter the cranial cavity? What is its path thereafter?
Via the foramen lacerum. Then arches upwards and forwards, grooving the medial wall of the cavernous sinus.
What accompanies the internal carotid artery? What branches does this give off?
The IC?? nerve of the sympathetic plexus. Branches to the orbit with the long ciliary nerves.
How is the abducens nerve related to the cavernous sinus?
Abducens approaches the cavernous sinus from posteriorly, then crosses the lateral and anterior walls to enter the superior orbital fissure
How is the oculomotor nerve related to the cavernous sinus? What is its course thereafter?
The oculomotor nerve approaches from the roof, then crosses the lateral wall inclining medially, and breaks into superior and inferior branches. It enters the superior orbital fissure medial to toehr structures, and picks up ICN??? branches
Where is the trigeminal ganglion found?
The anterior part lies forward in Meckel’s cave.
Give the divisions of the trigeminal ganglion
Mandibular, maxillary and ophthalmic
What is the course of the mandibular division of the trigeminal ganglion?
Passes downwards to the foramen ovale
What is the course of the maxillary division of the trigeminal ganglion?
Runs horizontally forward on the medial side of the lateral wall and passes through the foramen rotundum
What does the ophthalmic division of the trigeminal ganglion divide into? What crosses some of these?
Three branches in the anterior part. All three branches are crossed by the oculomotor nerve.
List the three branches of the anterior part of the trigeminal ganglion
Lacrimal and frontal
Nasociliary
What is the course of the lacrimal and frontal branches of the anterior part of the trigeminal ganglion?
These enter through the lateral part of the superior orbital fissure
What is the course of the nasociliary part of the trigeminal ganglion?
Enters through the medial part of the superior orbital fissure?
What nerve lies lateral to the 5th CN? What is found medial to the 6th cranial nerve?
No nerve lies lateral to the 5th. No nerve lies medial to the 6th.
Describe the course of the 4th cranial nerve relative to other cranial nerves
Runs parallel and higher with the 5th CN. Is lateral to the 3rd.
Describe the course of the 3rd cranial nerve
Slopes downwards crossing medial to both the 4th and the 5th
How does blood flow through the cavernous sinus?
May flow in either redirection and may communicate from one side to the other
What veins drain to the anterior part of the cavernous sinus?
The superior orbital vein and the inferior orbital vein - but the latter first drains to the pterygoid plexus
What drains to the roof of the cavernous sinus
The superficial middle cerebral vein
The sphenopalatine sinus
What sinus exits the cavernous sinus?
The superior petrosal sinus exits the posterior wall and enters the sigmoid sinus. It also drains the ear.
What empties the anterior compartment of the jugular foramen?
The inferior petrosal sinus, draining to the internal jugular vein
What passes to the pterygoid plexus?
The emissary vein
What does the inferior petrosal sinus drain?
The anterior compartment of the jugular foramen
How may infection from the cavernous sinus spread? To where and via what?
Via the superficial middle cerebral vein, skin infection can spread to the hemispheres.
Give two courses via which infection from the skin reaches the cavernous sinus
Angular vein, superior ophthalmic, cavernous sinus
Deep facial vein, pterygoid plexus, cavernous sinus
What does cavernous sinus thrombosis cause?
Opthlalmoplegia.
What thrombosis is usually fatal?
Retrograde thromboses to the inferior petrosal sinus
