Meninges Part 2

Question 1

Special features of pia matter??

Answer 1

Contain 21- denticulate ligament projections
Pia matter ends at L2 forming cona medullaris giving a structure a string known as filum terminalis till S2
While arachnoid and dura extend down also contain CSF in sub arachnoid space
Lumber puncture should done at L4-L5

Question 2

What are the folds of dura matter?

Answer 2

1- falx cerebri:
Divide vertically into right and left half
Start from Crista galli passes through the fissures of hemispheres backward and ends at the top of tentorium cerebelli
2- tentorium cerebelli :
Divide horizontally into upper and lower portion
Divide cranial cavity into supra(cerebral hemispheres) and infra( cerebellum, pons, medulla) tentorial area
Form the notch attached to clinoid process then progressively attached to both side of temporal bone and from back to occipital bone
3- diaphragma sellae
This fold is present between hypothalamus and pituitary gland
The hole in this fold allow the pituitary stalk to move down.

Question 3

Function of the folds of dura matter?

Answer 3

Mainly prevent the excessive movement of the brain within the cranial cavity

Question 4

Special features of dura matter?

Answer 4

It is pain sensitive
However brain is not ( no pain receptors)

Question 5

Nerve supply of dura matter?

Answer 5

Supra tentorial dura matter is supplied by the branches of opthalmic division and maxillary division of trigeminal systems.
So when there will be lesions in supra tentorial region of cranial cavity and involve the dura matter of anterior cranial fossa and middle cranial fossa - person will have pain in the forehead and maxillary region.

Infra tentorial region or dura matter of posterior cranial fossa have branch from vagus 10th nerve or has meningial branch from C1,C2,C3
If lesions like tumors are present in posterior cranial fossa the pain will be on back of head and neck.

Question 6

What are the spaces of CSF filled cavity?

Answer 6

1- Cranial epidural space ( potential space
2- vertebral epidural space ( real space) have loose areolar tissue, lymphatics, venous

Question 7

What are sub arachnoid cisterns??

Answer 7

CSF filled enlarged cavities known as cisterns
The CSF coming from foramen magendie into sub arachnoid space known as *cerebellomedullary cistern
The other foramen on the lateral side ( foramen luschka) leak into *cerebellopontine cistern
*Interpeduncular cistern
(Anterior part of midbrain known as cerebral peduncle divided into right and left peduncles, in between there is a gap known as interpeduncular cistern)
Back of the midbrain have CSF filled area known as *superior cistern
And both superior and interpeduncular cistern are connected with *ambient cistern