Neuroanatomy-Organization of the Brain Flashcards
What are cranial meninges?
Cranial meninges are coverings of the brain that lie immediately internal to the calvarium (skull)
What are the functions of the cranial meninges? (3)
- Protect the brain
- Form supporting framework for arteries, veins and venous sinuses
- Enclose the subarachnoid space (filled with CSF) which is vital to the normal function of the brain.
What are the 3 membranous connective tissue layers? Name their characteristics.
- Dura Mater (dura)- thick, external layer
- Arachnoid Mater (arachnoid)- thin, middle layer
- Pia Mater (pia)- delicate internal vascular layer that is adherent to the surface of the brain
What does CSF do? (2)
- Helps maintain the balance of extracellular fluid in the brain
- provides nutrients to the brain in part (but has less protein and different concentrations of sodium, potassium and calcium than blood)
What are the Leptomeninges composed of?
The leptomeninges are composed of arachnoid and pia layers.
What separates the arachnoid and pia layers?
The arachnoid layer is separated from the pia layer by the subarachnoid space which contains CSF.
Dura mater is also called?
Pachymeninges
Name the 2 layers of membranes that make up the dura mater.
- External Periosteal Layer- adherent to the inner table of the skull
- Internal Meningeal Layer
Name the infoldings of the dura mater and their overall function.
- Falx Cerebri
- Tentorium Cerebelli
- Falx Cerebelli
- Sellar Diaphragm
Inholdings of the dura mater separate regions to help stabilize the position of the brain.
Falx Cerebi
Separates the right and left hemispheres and runs along the interhemispheric fissure
Tentorium Cerebelli
Separates occipital lobes from the cerebellum
Falx Cerebelli
Vertical fold that separates the cerebellar hemispheres
Sellar Diaphragm
Smallest dural infolding which covers the pituitary gland and allows the infundibulum of the pituitary to pass through it.
Dura mater forms _______ between the _________ and _______ layers of the dura.
Dura mater forms the DURAL VENOUS SINUSES between the PERIOSTEAL and MENINGEAL layers of the dura
What is the function of the dural venous sinuses?
The dural venous sinuses provide the venous drainage for the brain and brainstem.
Name the dural venous sinuses. (6)
- Superior sagittal sinus
- Inferior sagittal sinus
- Straight sinus
- Confluence of sinuses (torculum)
- Transverse Sinuses
- Sigmoid Sinuses
Characteristics of Vasculature of the Dura (2)
- most dural branch arteries supply more blood to the calvarium the the dura.
- the largest is the middle meningeal artery (branch of the maxillary artery) which enters the middle cranial fossa via foramen spinosum
Venous drainage
-drainage of the dura via dural emissary veins, which travel alongside the meningeal arteries and drain into the dural venous sinuses.
Nerve supply to the dura is by which nerve(s)?
From the meningeal branches of all 3 divisions of the trigeminal nerve (CN V) - ophthalmic (V1), Maxillary (V2) and Mandibular (V3).
Space between the cranium and the periosteal layer of the dura.
Space between the cranium and the periosteal layer of the dura.
Epidural Hematoma
Epidural hematoma is the filling of blood in the epidural space following head trauma most often associated with the tearing of the meningeal arteries.
Subdural Hematoma
Subdural Hematoma is the filling of blood wishing the subdural space following head trauma most often associated with the tearing of the emissary (bridging) veins
Space between the arachnoid and pia layers
Subarachnoid Space
Most common problems involving the subarachnoid space
Free blood within secondary to trauma or a ruptured aneurysm
Spaces considered to be a “potential space” meaning the space only becomes a space pathologically
- Epidural Space
- Subdural Space
Space considered a “real space” meaning it contains CSF, arteries and veins
Subarachnoid space
