1. Meninges
D.Nimer D.Rania Gabr
D.Safaa D.Elsherbiny

2. Objectives
Describe the arrangement of the meninges and their relationship to brain and spinal cord.
Explain the occurrence of epidural, subdural and subarachnoid spaces.
Locate the principal subarachnoid cisterns, and arachnoid granulations.
Describe the ventricles of brain and importance of their choroids plexus.
Summarize the pathway of cerebrospinal fluid (CSF) circulation
Identify brain ventricles in CT scan, MRI .

3. MENINGES The brain and spinal cord are surrounded by three membranes:
1. Dura mater: it is the outermost layer.
2. The arachnoid mater: the middle one.
3. The pia mater: the inner one.

6. Cranial Meningeal Spaces
Epidural space
Potential space superior to dura (between bone and dura). Normally closed since the dura is
attached to the periosteum
which is attached to the
inner surface of the skull. In the spinal cord it contains adipose CT
Subdural space
Potential space between dura and arachnoid mater. Contains dural veins.
Subarachnoid space
Filled with CSF
Contains the cerebral arteries supplying brain.

7. Cranial Meningeal Spaces Cerebral arteries & CSF
Epidural space
Meningeal arteries
Subdural space
Dural veins
subarachnoid space
Cerebral arteries & CSF
Brain

8. Epidural hematoma

11. DURA MATER
The cranial dura is a two layered tough, fibrous membrane that surrounds the brain.
It is formed of two layers:
The periosteal layer: is attached to the skull.
The meningeal layer: it covers the brain is folded
These are closely united except along certain lines, where they separate to form venous sinuses.

12. DURAL Folds The meningeal layer sends inward five septa: Falx cerebri
Falx cerebelli
Tentorium cerebelli
Diaphragma sellae
Cavum trigeminal

14. Falx cerebri Def: Is a sickle-shaped fold of dura mater
Site: between the two cerebral hemispheres
Shape: sickle shape
Attachments:
1. Apex: attached to the frontal crest and the crista galli.
2. Base: with the upper surface of the tentorium cerebelli.
3. Upper border: to superior sagittal suture.
4. Lower border: free, above corpus callosum

15. Falx cerebri Sinus contents:
The superior sagittal sinus  in the upper border.
The inferior sagittal sinus  in the lower border (posterior 2/3).
The straight sinus  at the base, between the falx cerebri and the tentorium cerebelli in the median plane. 1 2 3

16. Tentorium cerebelli
Def: reduplication of inner layer of dura over the posterior cranial fossa.
Shape: tent-shaped fold
Site: between the cerebrum & the cerebellum.
Tentorium cerebelli

17. Tentorium cerebelli
Superior surface  gives attachment to the falx cerebri
Inferior surface  gives attachment to the falx cerebelli
Anterior border (free)  surrounds the midbrain (tentorial notch)
Posterior border (attached)  attached to the upper border of the petrous part of the temporal bone and the lips of the groove for the transverse sinus.

18. Tentorium cerebelli Sinus contents:
The superior petrosal sinus: in the posterior border
The transverse sinus: in the posterior border
The straight sinus: at the junction between the flax cerebri and the tentorium cerebelli in the median plane. 3 2

19. Falx cerebelli
Def: reduplication of inner layer of dura between the 2 cerebellar hemispheres.
Shape: triangular in shape
Site: between the 2 cerebellar hemispheres..

20. Falx cerebelli Sinus contents: The occipital sinus
Base attached to inferior surface of tentorium cerebelli
Apex at posterior part of foramen magnum
Anterior border (free)  related to vermis
Posterior border (attached)  attached to internal occipital crest
Sinus contents: The occipital sinus

21. Diaphragma sellae
Def: reduplication of inner layer of dura that covers pituitary gland
Shape: It is a small circular fold. It has a central hole which transmit the infundibulum of the pituitary gland.
Site: covering sella turcica
Attachment:
Anterior  attached to tuberculum sellae
Posterior border attached to dorsum sellae
Sinus content: The anterior and posterior intercavernous sinuses.

23. Arachnoid Mater& Pia Mater
The arachnoid mater is a soft, impermeable , translucent membrane loosely envelops the brain.
The pia mater is the innermost, thin, delicate & highly vascular membrane that is closely adherent to the gyri and fitted into the sulci.

24. Blood supply of the dura mater Nerve supply of the dura mater
In the anterior cranial fossa:
ophthalmic, anterior and posterior ethmoidal arteries.
In the middle cranial fossa
Middle meningeal, accessory meningeal arteries.
internal carotid arteries and ascending pharyngeal arteries.
In the posterior cranial fossa:
Meningeal branches of the occipital, vertebral arteries.
Nerve supply of the dura mater
Trigeminal, facial, glossopharyngeal and vagus nerves
Upper 3 cervical nerves