CAVERNOUS SINUS Flashcards
(33 cards)
What cranial nerves are located in the lateral wall of the cavernous sinus from superior to inferior?
CN III (Oculomotor), CN IV (Trochlear), CN V1 (Ophthalmic division), CN V2 (Maxillary division)
Explanation: These nerves are embedded in the lateral wall of the CS. The mandibular division (V3) does not pass through the CS.
Which cranial nerve is located within the venous sinusoids of the cavernous sinus?
CN VI (Abducens nerve)
Explanation: Unlike other nerves that run in the lateral wall, the abducens nerve passes through the venous compartment of the CS, adjacent to the ICA.
What is Meckel’s cave and which structure does it contain?
Meckel’s cave is a CSF-filled dural outpouching that contains the trigeminal (gasserian) ganglion.
Explanation: It communicates with the prepontine cistern and is positioned adjacent to the CS.
What are the venous connections of the cavernous sinus?
Superior/inferior ophthalmic veins, sphenoparietal sinus, intercavernous plexus, petrosal sinuses, basilar venous sinus, pterygoid venous plexus
Explanation: These connections allow the CS to communicate with intracranial and extracranial venous systems.
What are the five walls of the cavernous sinus?
Anterior, Posterior, Medial, Lateral, Superior (Roof)
Explanation: Each wall has distinct anatomic boundaries and relations, such as the anterior wall extending to the superior orbital fissure and the medial wall adjoining the pituitary.
Why is the upper sellar medial wall of the CS prone to invasion by pituitary tumors?
Because it is composed of a thin, single-cell layer of dura.
Explanation: This structural weakness allows for easy tumor extension into the CS.
What imaging modality is preferred for evaluating the cavernous sinus?
MRI with and without contrast
Explanation: MRI provides superior soft tissue resolution, particularly using thin-section coronal and axial sequences with gadolinium.
What is the typical enhancement pattern of the cavernous sinus in imaging?
It enhances symmetrically; however, asymmetry can be seen during early arterial or venous phases.
Explanation: Asymmetric enhancement should not always be considered pathological—timing matters.
What cranial nerves are located in the lateral wall of the cavernous sinus from superior to inferior?
CN III (Oculomotor), CN IV (Trochlear), CN V1 (Ophthalmic division), CN V2 (Maxillary division)
Explanation: These nerves are embedded in the lateral wall of the CS. The mandibular division (V3) does not pass through the CS.
Which cranial nerve is located within the venous sinusoids of the cavernous sinus?
CN VI (Abducens nerve)
Explanation: Unlike other nerves that run in the lateral wall, the abducens nerve passes through the venous compartment of the CS, adjacent to the ICA.
What is Meckel’s cave and which structure does it contain?
Meckel’s cave is a CSF-filled dural outpouching that contains the trigeminal (gasserian) ganglion.
Explanation: It communicates with the prepontine cistern and is positioned adjacent to the CS.
What are the venous connections of the cavernous sinus?
Superior/inferior ophthalmic veins, sphenoparietal sinus, intercavernous plexus, petrosal sinuses, basilar venous sinus, pterygoid venous plexus
Explanation: These connections allow the CS to communicate with intracranial and extracranial venous systems.
What are the five walls of the cavernous sinus?
Anterior, Posterior, Medial, Lateral, Superior (Roof)
Explanation: Each wall has distinct anatomic boundaries and relations, such as the anterior wall extending to the superior orbital fissure and the medial wall adjoining the pituitary.
Why is the upper sellar medial wall of the CS prone to invasion by pituitary tumors?
Because it is composed of a thin, single-cell layer of dura.
Explanation: This structural weakness allows for easy tumor extension into the CS.
What imaging modality is preferred for evaluating the cavernous sinus?
MRI with and without contrast
Explanation: MRI provides superior soft tissue resolution, particularly using thin-section coronal and axial sequences with gadolinium.
What is the typical enhancement pattern of the cavernous sinus in imaging?
It enhances symmetrically; however, asymmetry can be seen during early arterial or venous phases.
Explanation: Asymmetric enhancement should not always be considered pathological—timing matters.
Which vein communicates with the cavernous sinus through the superior orbital fissure?
The superior ophthalmic vein.
Explanation: It enters the CS via the superior orbital fissure and is a key route for infection spread from the face to the cavernous sinus.
What structure separates the optic canal from the superior orbital fissure?
The optic strut.
Explanation: This thin bony strut separates the optic nerve in the optic canal from the structures in the SOF.
What is the typical location of the pituitary infundibulum on imaging?
Posterior to the optic chiasm within the suprasellar cistern.
Explanation: It enhances avidly on contrast-enhanced MR imaging.
Which segment of the ICA is located within the cavernous sinus?
The cavernous segment of the ICA.
Explanation: It enters after the lacerum segment and gives off several branches including the meningohypophyseal trunk.
What is the Dorello canal and what does it contain?
It is a small space containing the abducens nerve (CN VI) and venous tissue.
Explanation: Located near the petrous apex, it connects the prepontine cistern with the CS.
What is the oculomotor triangle?
A triangular dural region of the CS roof through which CN III and CN IV pass.
Explanation: It is bordered by the anterior and posterior petroclinoid folds and the interclinoid fold.
Which cranial nerve is embedded most inferiorly in the lateral wall of the CS?
CN V2 (Maxillary nerve).
Explanation: It lies just above the exit point foramen rotundum.
What pathology is indicated by non-enhancing internal compartments of the CS on MR imaging?
Cavernous sinus thrombosis.
Explanation: Lack of enhancement within CS on contrast images is a key sign.
