a view about brain covering and their classification , function , location as well as spinal cord ,,

1. Meninges of Brain and
Spinal Cord
DR: aasim billal

2. Dura mater
• It is the outermost of the three
layers of the meninges
surrounding the brain and spinal
cord
• It is derived from mesoderm
• The name dura mater is derived
from Latin "tough mother", a loan
translation of Arabic ‫الدماغ‬ ‫أم‬
‫الصفيقة‬umm al-dimāgh aṣ-
ṣafīqah), literally thick mother of
the brain

3. Dura mater
• It surrounds and supports
the dural sinuses
• Dura mater has two layers:
• The superficial layer, which
serves as the skull's inner
periosteum; (periosteal
layer)
• The deep layer; (meningeal
layer)

4. Dura mater Modifications
• Falx cerebri
• Falx cerebelli
• Tentorium cerebelli
• Diaphragma sellae

5. Dura mater: Falx cerebri
• Sickle shaped double layer of dura
mater, lying between cerebral
hemispheres
• Attached anteriorly to crista galli
• Attached posteriorly to tentorium
cerebelli
• Has a free inferior concave border
that contains inferior sagittal sinus
• Upper convex margin encloses
superior sagittal sinus

6. Dura mater: Falx cerebelli
• Small sickle shaped
projection between the
cerebellar hemispheres
• Attached to posterior
parts of tentorium
cerebelli

7. Tentorium cerebelli
• Crescentic fold of dura
mater
• Supports occipital lobes
of cerebrum and covers
cerebellum
• External convex border
encloses transverse sinus
posteriorly and superior
petrosal sinus anteriorly

8. Diaphragma sellae
• Circular, horizontal fold
of dura mater that
forms the roof of sella
turcica, covering the
pituitary gland
• Has a central aperture
for the hypophysial
stalk

9. Arachnoid Mater
• It forms a loose investment for the brain
• Connected by delicate connective tissue with both
the dura and pia mater
• It surrounds the nerves, forming tubular sheaths for
them as far as their points of exit from the skull.
• It is continued downward over the spinal cord
• CSF flows in the sub arachnoid space .

10. Subarachnoid space
• Space between arachnoid and pia
mater
• Occupied by spongy tissue
consisting of trabeculae (delicate
connective tissue filaments that
extend from the arachnoid mater
and blend into the pia mater) and
intercommunicating channels in
which the cerebrospinal fluid is
contained

11. Subarachnoid space

12. Pia Mater
• The thin membrane is composed of fibrous
tissue, which is covered by a sheet of flat cells
impermeable to fluid on its outer surface
• A network of blood vessels travels to the brain
and spinal cord by interlacing through the pia
membrane
• These capillaries are responsible for nourishing
the brain

13. Dura Mater of Spinal Cord
• The spinal cord, like the brain, is surrounded by
the three meninges
• The dura is attached to the foramen magnum
and the periosteium covering the uppemost
cervical vertebrae and their ligaments
• Through the remainder of the vertebral canal,
the dura is not attached to the vertebrae, being
separated by the epidural (or peridural or
extradural) space, which contains fat and the
internal vertebral venous plexus

14. Arachnoid Mater of Spinal Cord
• The arachnoid invests the spinal cord loosely
• Continuous with the cerebral arachnoid above, it traverses the
foramen magnum and descends to about the S2 vertebral level
• The subarachnoid space, which contains cerebrospinal fluid (C.S.F.),
is a wide interval between the arachnoid and pia
• Because the spinal cord ends at about the level of the L2 vertebra,
whereas the subarachnoid space continues to S2, access can be
gained to the C.S.F. by inserting a needle between the vertebral
lamina below the end of the cord, a procedure termed lumbar
puncture
• By this means, the pressure of C.S.F. can be measured, the fluid can
be analyzed, a spinal anesthetic can be introduced, or fluid can be
replaced by a contrast medium for radiography (myelography)

15. Pia Mater of Spinal Cord
• The pia mater invests the spinal cord closely,
ensheathes the anterior spinal artery (as linea
splendens), and enters the anterior median fissure
• Laterally, the pia forms a discontinuous longitudinal
septum, the denticulate ligament, which sends about
21 tooth-like processes laterally to fuse with the
arachnoid and dura on each side
• The ligament is a surgical landmark in that it is
attached to the spinal cord about midway between
the attachments of dorsal and ventral roots

16. Meninges of Spinal Cord

17. Meninges of Spinal Cord

18. Any Question ???