Neuro 7: meninges, ventricular system, CSF

subarachnoid space

where is CSF found?

1. periosteal layer (attached to inner surface of cranium)

2. meningeal layer (adheres to arachnoid mater)

what are the two layers of the dura mater in the cranium?

false (attached to the inner surface of the cranium but not attached to the spinal cord = epidural space)

T/F: the dura mater is always attached to bone

dural reflections/folds

projections of the dura mater that form septa to provide structure support

dural venous sinuses

venous channels between the two layers of the dura mater

internal jugular vein (IJV)

where do the dural venous sinuses drain?

falx cerebri

midline projection located in the longitudinal fissure that separates the left and right cerebral hemispheres; attaches to the crista galli anteriorly

tentorium cerebelli

transverse projection between the occipital lobes and the cerebellum; attaches anteriorly to the clinoid process and laterally to the petrous portion of temporal bone

1. falx cerebri

2. tentorium cerebelli

1. falx cerebri

2. tentorium cerebelli

falx cerebelli

median projection between the cerebellar hemispheres

diaphragma sella

projection that forms a roof over the pituitary fossa and has a opening in it for the infundibular stalk of the pituitary gland

diaphragma sella

black arrow

arachnoid trabeculae

thin CT septa on the inner surface of the arachnoid that attach to the pia mater

arachnoid granulations

mushroom-shaped structures that project through the dura into the dural venous sinuses; function as one-way valves to transfer CSF

arachnoid trabeculae

black arrows

arachnoid granulations

blue arrow

filum terminale externum

fibrous bands that connects the dura mater to the coccyx in the spinal cord

lumbar cistern

formed by the subarachnoid space from the conus medullaris to the second sacral vertebra; location of a spinal tap

denticulate ligaments

fibrous bands that attach from the pia mater to the arachnoid mater in the spinal cord

filum terminale internum

pia mater extension that attaches to the dural sac at the tip of the conus medullaris

middle meningeal

primary arterial supply to the meninges

1. meningeal branches from opthalmic artery

2. ethmoidal arteries

additional blood supply to the anterior cranial fossa besides the middle meningeal artery

1. ascending pharyngeal artery

2. occipital artery

3. vertebral artery

additional blood supply to the posterior cranial fossa besides the middle meningeal artery

all three branches of trigeminal nerve (ophthalmic, maxillary, mandibular)

what innervates the anterior and middle fossa?

dorsal roots of C2-C3

what innervates the posterior fossa?

tentorial nerve from ophthalmic CN V1

what innervates the tentorium cerebelli?

sympathetic from superior cervical ganglion (autonomic fibers)

what innervates the vessels of the dura

recurrent meningeal nerve

what innervates the spinal dura in every level?

ependymal cells

what cells line the ventricles?

choroid plexus

vascularized cuboidal epithelial cells with microvilli

anterior/frontal horn of lateral ventricles

1

body of lateral ventricles

2

atrium

3

posterior/occipital horn (occipital lobe)

4

inferior/temporal horn (temporal lobe)

5

2 interventricular foramens

red arrow

third ventricle (diencephalon)

6

cerebral aqueduct

black arrow

fourth ventricle (pons and medulla)

7

corpus callosum

1

septum pellucidum

2

fornix

4

lateral ventricles

3

caudate nucleus

5

thalamus

red arrow

third ventricle

green dot

corpus callosum

1

lateral ventricles

3

fornix

4

choroid plexus

12

one

how many third ventricles?

2

how many lateral ventricles

third ventricle

where is the largest choroid plexus?

1. lateral ventricles

2. interventricular foramen (foramen of munro)

3. third ventricle

4. cerebral aqueduct

5. fourth ventricle

6. subarachnoid space

describe the flow of CSF

tight junctions (active transport only)

what kind of junctions between the cells in the blood brain barrier

rupture of middle meningeal artery due to fracture of the temporal lobe

most common cause of epidural hematoma?

kids

epidural hematomas are more common in?

subdural

hematoma between the dura and arachnoid

rupture of bridging veins (as it leaves the subarachnoid space to enter the dura)

what is the most common cause of subdural hematomas?

elderly (brain atrophy from aging and alcohol)

subdural hematomas are more common in ?

1. head trauma

2. rupture of intracranial aneurysm (non-traumatic)

most common cause of subarachnoid hemorrhage

arachnoid villa cells

where do meningiomas usually start?

cranial cavity (90% vs. 9% in spinal cord)

where are meningiomas most commonly found?