The three meninges that surround and protect the brain and spinal cord are the dura mater, arachnoid mater, and pia mater. The dura mater is the outermost layer and is a thick, fibrous membrane that divides the cranial cavity into compartments. It contains venous sinuses that drain blood from the brain. The arachnoid mater is the intermediate layer separated from the pia mater by the subarachnoid space, which contains cerebrospinal fluid. The pia mater is the innermost layer that is closely applied to the surface of the brain.

1. MENINGES
Rabbia Yousaf
(Pharm-D)
Rashid Latif College of
Pharmacy

2. THE MENINGES
• Three concentric membranes that entirely
envelope the brain and spinal cord and
provide support and protection.

4. 1. Dura mater
2. Arachnoid mater
3. Pia mater

6. Dura mater
• Outermost layer
• An opaque, tough, fibrous coat.
• Incompletely divides the cranial cavity into
compartments and accommodates the dural
venous sinuses.
• Separated from the arachnoid by a narrow
subdural space.

7. • Cranial dura matter is composed of two layers:
1.THE ENDOSTEAL LAYER (Outer)
2.THE MENINGEAL LAYER (Inner)
They are united except where they separate to
enclose the venous sinuses that drain blood
from the brain.

8. THE ENDOSTEAL LAYER
• The periosteum covering the inner surface of
the skull bones.

9. THE MENINGEAL LAYER
• proper dura mater
• dense, strong fibrous membrane
• Provides tubular sheaths for the cranial nerves
as they exit skull.

11. Dural Venous Sinuses
• A complex of venous channels that lie
between the two layers of dura mater,
draining blood from the brain and cranial
bones.
• They are lined by endothelium and have no
valves; their walls are devoid of muscular
tissue.

12. • Sends inward 4 septa, which divide the cranial
cavity into freely communicating spaces that
lodge the subdivisions of the brain.
• These septa restrict the displacement of the
brain associated with acceleration and
deceleration, when the head is moved.

14. • FALX CEREBRI
• Sickle-shaped fold of dura mater
• Lies in the midline between the two cerebral
hemispheres.
1.The superior sagittal sinus runs in its upper fixed
margin,
2.The inferior sagittal sinus runs in its lower
concave free margin
3.The straight sinus runs along its attachment to
the tentorium cerebelli.

15. THE FALX CEREBELLI
• small, sickle-shaped fold of dura mater
• projects forward between the two cerebellar
hemispheres.
• Its posterior fixed margin contains the
occipital sinus.

16. THE TENTORIUM CEREBELLI
• Crescent-shaped fold of dura mater
• roofs over the posterior cranial fossa.
• It covers the upper surface of the cerebellum
and supports the occipital lobes of the
cerebral hemispheres.
• In the anterior edge there is a gap, the
tentorial notch, for the passage of the
midbrain.

17. • The falx cerebri and the falx cerebelli are
attached to the upper and lower surfaces of
the tentorium, respectively.
• THE STRAIGHT SINUS runs along its
attachment to the falx cerebri,
• THE SUPERIOR PETROSAL SINUS runs along its
attachment to the petrous bone.
• THE TRANSVERSE SINUS runs along its
attachment to the occipital bone.

18. THE DIAPHRAGMA SELLAE
• a small, circular fold of dura mater that forms
the roof for the sella turcica.
• A small opening in its center allows passage of
the stalk of the hypophysis cerebri.

19. • Dural Venous Sinuses
• Situated between the layers of the dura mater.
• Their Main function is to receive BLOOD and
CSF.
• Blood from the brain through the cerebral
veins
• CSF from the subarachnoid space through the
arachnoid villi.

20. • Blood in the dural sinuses ultimately drains
into the internal jugular veins in the neck.
• They have no valves.

21. • DURAL NERVE SUPPLY
• Branches of the 5th ,10th and the 1st 3 cervical
spinal nerves and branches from the
sympathetic trunk pass to the dura.

22. • DURAL BLOOD SUPPLY
• Numerous arteries supply the dura mater
from the internal carotid, maxillary,
ascending pharyngeal, occipital, and
vertebral arteries.
• Clinically the most important is the middle
meningeal artery, which can be damaged in
head injuries.

24. Pia Mater
• Innermost layer.
• Closely applied to surface of brain.
• Dips into fissures and sulci.
• Forms sheath around blood vessels as they
penetrate surface of brain.

26. Arachnoid
• Intermediate layer.
• Attached to dura mater and pia mater:
Separated from pia mater via:
Subarachnoid space:
Contains cerebrospinal fluid
• With many arachnoid villi:
For reabsorption of cerebrospinal fluid.
Arachnoid granulations may pit
surrounding bone:
Fovea granulares.