Dural Sinuses And Meninges Flashcards
Which layer of the meninges is the strongest?
Dura mater
What are the two layers of the dura mater?
Periosteal and meningeal layer
What is the periosteal layer of the dura mater?
More superficial layer
Attaches to the periosteum of the cranial bones
Describe the meningeal layer of the dura mater
Lies deep to the periosteal layer
Usually fused to the periosteal layer except in specific areas where the two layers separate to form large, blood-filled spaces called dural venous sinuses
Which mater lies immediately internal to the dura mater?
Arachnoid mater
What are arachnoid trabeculae?
Delicate web of collagen and elastic fibers that partially compose the arachnoid mater
Where is the subdural space?
Between the arachnoid and the overlying dura mater
Where is the subarachnoid space?
Immediately deep to the arachnoid
Which mater is the innermost of the cranial meninges?
Pia mater which is a thin layer of CT that tightly adheres to the brain and follows every contour of the brain surface
What is dural septa?
Extensions of the dura mater that are flat partitions (septa) going deep into the cranial cavity at 4 locations
What are the four membranous partitions that separate specific parts of the brain and provide additional stabilization and support to the entire brain?
Falx cerebri, tentorium cerebelli, falx cerebelli and diaphragm sellae
What is located within the cranial dural septa?
Dural venous sinuses such as the superior and inferior sagittal sinuses, the straight sinus, sigmoid sinus and transverse sinus
Which structures are located within the cavernous sinus?
Internal carotid artery, pituitary gland, CN V1-3, CN IV (Trochlear), III (oculomotor) and VI (abducens)
Which structure within the cavernous sinus is the only one that sits freely within it and is not within the wall?
Abducens nerve (CN VI)
Which part of the internal carotid artery is within the cavernous sinus?
Cavernous part
What is a cavernous sinus thrombosis?
A blood clot within the cavernous sinus usually caused by an infection that spreads from the paranasal sinuses
What are the clinical signs of a cavernous sinus thrombosis?
High fever, periorbital edema and chemosis (conjunctival edema), CN palsies (most commonly CN VI with lateral gaze), decreased visual acuity
How is a cavernous sinus thrombosis diagnosed?
CT or MRI scans
What is the treatment for a cavernous sinus thrombosis?
IV abx, heparin (blood thinner), surgery
What causes the spread of infection leading to a cavernous sinus thrombosis?
Due to the anastomosis between the facial vein and superior opthalamic veins
What do all dural venous sinuses drain into?
Internal jugular vein
The straight, superior and inferior sagittal sinuses are all found in the falx cerebri and converge at the what?
Confluence of sinuses
The straight sinus is a continuation of what?
The great cerebal vein and inferior sagittal sinus
From the confluence of sinuses, the transverse sinus continues bilaterally and curves into what?
The sigmoid sinus to meet the opening of the internal jugular vein
What does the cavernous sinus drain?
The opthalamic veins and from blood returns to the IJV via the superior or inferior petrosal sinuses
