Control L4 meninges and ventricles Flashcards
How many layers of the meninges surround the CNS?
3
What is the function of the meninges?
To protect the CNS
What is the outer layer of the meninges called?
The dura mater
What is the middle layer of the meninges?
Arachnoid mater
What is the inner layer of the meninges called?
The pia mater
What is the toughest layer of meninges?
The dura mater
What artery is in the dura mater?
The middle meningeal artery
What injury is caused by a bleed from the middle meningeal artery?
An extradural haemorrhage
What properties does the dura mater have?
Tough, fibrous, protective
What are the properties of the arachnoid mater?
Thin, delicate and spider web like
What is the most vascular layer of the meninges?
The arachnoid layer
What are the properties of the pia mater?
Microscopically thin and follows the gyri and sulci
How many layers of cranial dura /is the dura mater split into?
2
What are the two layers of the dura mater callled?
Periosteal and meningeal dura mater
Between which layers are the arachnoid villi/granulations located?
The periosteal dura and meningeal dura
What is the space between the arachnoid mater and pia mater called?
The subarachnoid space
Which layers of the skull/brain are fused in real life?
The skin, skull and dura and arachnoid mater
What fills the subarachnoid space?
Arteries and veins and cerebral spinal fluid (CSF)
What forms the double layers dural fold/septa?
The separation of the inner and outer dural layer. The inner dural layers fuse together producing a fold
Where is the main dural fold?
Separating the hemispheres of the brain
What is contained in the space between the inner and outer dural layers at the dural fold?
Dural venous sinus containing venous blood
What are the three dural folds? Where are they found?
The falx cerebri - in sagittal plane -separating two cerebral hemispheres = crescent shape
The tentorium cerebelli - in horizontal plane - separates the cerebrum and cerebellum
The flax cerebelli- in sagittal plane - separates the cerebellum hemispheres
What bone does the falx cerebri attach to?
The crysta galli of the ethmoid bone and the internal occipital tuberance of the occipital bone
What is the name of the dural venous sinus at the falx cerebri?
The superior sagittal sinus
What is the name of the dural venous sinus at the tentorium cerebelli?
The transverse sinus
How many transverse sinuses are there?
2 - one on each side of the head
What causes dural venous sinuses in the brain?
Separation of the dural layer
What is different about the meningeal layers in the spine compared to the brain?
Only one layer of dura mater - meningeal dura only
There is a layer of fat between the dura and the vertebrae
What is the spinal cord enclosed in?
A dural sac
Spinal nerve roots are ensheathed in dura. True or false?
True
What is the space with layer of fat in the dura sac in the spine called?
The epidural sac
Both the brain and spinal cord have a subarachnoid space containing CSF. True or false?
True
What is the name of the ligaments in the dural sac?
Denticulate ligaments
What layer are the denticulate ligaments from?
The pia mater
Where on a cadaver are denticulate ligaments?
Between each spinal nerve
The dura mater is not attached to the arachnoid mater in the spinal cord of a healthy person. True or false?
False
What are potential/pathological areas of space in the meninges?
The epidural space in the cranial cavity and the subdural space in both the brain and spinal cord
What are real areas of space in the minges?
The epidural space in the spinal cord and the subarachnoid space in both the brain and spinal cord
In what part of the meninges does an extradural haemorrhage?
In the epidural space of the brain/skull
Where does CSF come from?
A filtrate from blood produced in ventricles by specialised areas of the ventricular lining called the choroid plexus
What are the properties of CSF?
Clear and colourless fluid
Contains glucose and inorganic salts
Has little proteins and few cells
What is the function of CSF?
Provides physical protection and chemical stability for the CNS
How many vesicles are in the brain?
4
What are the two ‘canals’ in the ventricular system of the brain?
The cerebral aqueduct and the central canal
Why do the cerebral hemispheres adopt a c-shape?
Due to the folding of the telencephalon over the diencephalon during development
What does the ventricular system look like from the side?
Like a hand grabbing a dragon or an alien in a space ship
What are the largest ventricles in the brain?
The lateral ventricles
How many lateral ventricles are there?
2 - one in each hemisphere
Where in the brain are the lateral ventricles found?
In all lobes of the cerebral hemisphere
Where in the brain is the 3rd ventricle located?
Below the thalamus
Where in the brain is the 4th ventricle located?
Posterior to the brainstem on the inferior aspect of the pons and superior aspect of the medulla oblongata, anteriorly to the cerebellum
What are the five main areas of the lateral ventricle?
The anterior horn
The body
The antrum
The posterior horn
The inferior horn
Where is the intra ventricular foramen?
Between the anterior horn and the 3rd ventricle
What connects the 3rd ventricle to the 4th ventricle?
The cerebral aqueduct
How does the CSF leave the ventricles into the subarachnoid space?
Out of the Luschka foramina/lateral apertures and the Magendie foramen/the medial aperture of the 4th ventricle
Where are the chorid plexuses found?
In the ventricles of the brain
What is the function of the choroid plexus?
To filter the blood and produce CSF
Where is CSF reabsorbed?
At the arachnoid granulations/villi into the venous circulation at the superior sagittal sinus
What are cisterns?
Expansions of the subarachnoid space
What is the most important cistern in the brain?
The lumbar cistern
Where is a CSF sample usually take from?
The lumbar cistern
Why is CSF sample usually taken from the lumbar cistern?
As the spinal cord has usually ended (between T12-L3) so less risk of puncturing the spinal cord
What vein does CSF usually end up in?
The IJV
What causes hydrocephalus?
Accumulation of CSF in the brain due to a blockage in the draining system.
