1. Meninges
• The spinal cord and brain are surrounded by three membranes,
the meninges. Named from the outside inward they are the
dura mater, arachnoid, and pia mater.
2.
3.
4. Dura mater
Characters
• A thick and dense inelastic membrane that composed of two layers, an inner or
meningeal and outer or periosteal.
• It is in loose contact with calvaria, and most strongly adherent to base of skull.
Periosteal layer:
• Like ordinary periosteum layer.
• Covers inner surface of skull.
• Doesn't extend through foramen magnum to become continuous with spinal
duramater.
5. Meningeal layer:
• Inner fibrous layer, closer to brain.
• Continuous with spinal duramater.
• Provides tubular sheath for cranial nerves.
• It sends inward four septa that divide cranial
cavity into freely communicating spaces.
Both layers are closely related except w/n they
make venous sinuses.
6.
7. Septa
Falx cerebri:
• the largest, sickle-shaped.
• Midline fold of dura mater extending between two cerebral hemispheres.
• Narrow end infront attached with crista galli.
• Broad posterior part blends in mid line with upper surface of tentorium
cerebelli.
• Superior sagittal sinus runs in its upper fixed margin.
• Inferior sag. Sinus runs in lower concave free margin.
• Straight sinus runs along its attachment to tentorium cerebelli.
8.
9. Tentorium cerebelli:
• Crescent shape.
• Dural fold located between cerebellum and
occipital lobes of cerebral hemispheres.
Falx cerebelli:
• Small sickle shape fold.
• Dural fold between two cerebellar hemispheres.
• Its posterior fixed margin contains Occipital sinus.
10. Diaphragma sellae:
• Small circular folds.
• Dural fold over hypophyseal fossa (pituitary).
• completely roofs the fossa hypophyseus of
the sella turcica a part of the sphenoid bone.
14. Dural venous sinuses
1. Superior sagittal sinus:
Lies along superior margin of falx cerebri.
2. Inferior sagittal sinus:
Lies along inferior margin of falx cerebri.
3. Straight sinus:
Lies at intersection of falx cerebri and tentorium cerebelli.
15. 4. Confluence of sinuses:
Common confluence of superior sagittal sinus and straight sinus.
5. Transverse sinus: (Paired)
Begins at confluence of sinuses.
Extends along edges of tentorium cerebelli.
Right receives blood from superior sagittal sinus.
Left receives blood from straight sinus.
6. Sigmoid sinus:
Continuation of straight sinus.
“S”-shaped.
Ends at jugular foramen:
Joins internal jugular vein.
16. 7. Cavernous sinus: (Paired)
lies on each side of sella turcica
8. Occipital sinus:
Lie in posterior fixed margin of falx cerebelli.
9. Superior & Inferior petrosal sinus: (Paired)
Small & situated on the sup & inf borders of
petrous part of temporal bone.
17. The flowing of the blood in dural sinus
Sup. sagittal sinus
Inf. sagittal sinus Straight sinus Confluence of sinus Transverse sinus
Cavernous sinus
Sup. petrosal sinus
Inf. petrosal sinus Internal jugular vein
Sigmoid sinus
18. Subdural space
Potential space between dura and arachnoid
mater.
Cranial Meningeal Spaces
Epidural space
Potential space superior to dura.
Subarachnoid space
Filled with CSF
Contains the blood vessels supplying brain.
19. Arachnoid mater
• Characters: a delicate membrane covering brain loosely, passing over
sulci and entering only cerebral longitudinal and transverse fissures.
• Subarachnoid cisternae
– Cerebellomedullary cistern (b/w inferior surface of cerebellum & roof of 4th
ventricle)
– Interpeduncular cistern (b/w two cerebral peduncles).
• Arachnoid projects into venous sinus as Arachnoid villi most numerous
in superior sagittal sinus.
20. • Aggregation of these are called Arachnoid
granulations w/c serve as sites where cerebrospinal
fluid diffuses into bloodstream.
• Structures passing to & from brain or its foramina
must pass through S.A.S.
21. 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.
• Fuses with the epineurium.
• pia invaginates into ventricles to take part in
the formation of choroids plexus
22. Cerebrospinal fluid (CSF)
• Cerebrospinal fluid is a clear colorless fluid,
which acts as a transport medium for nutrients
and waste products and provides a protective
fluid cushion for the central nervous system.
• Production: produced by the choroids plexuses
within the lateral, third and fourth ventricles
23. Circulation of cerebrospinal fluid
CSF drains from lateral ventricle interventricular foramina third ventricle
mesencephalic aqueduct
fourth ventricle median and two lateral apertures
subarachnoid space arachnoid granulations superior sagittal sinus vein
28. • Basilar artery:
Formed by union of 2 vertebral arteries
ascending in a groove on anterior surface of
pons.
• Branches:
1. Pontine artery
2. Anterior inferior cerebellar artery
3. superior cerebellar artery
4. posterior cerebellar artery
29. Cerebral arterial circle ( circle of Willis )
• Formation: formed by
anterior communicating
artery, anterior cerebral
arteries, internal carotid
arteries, posterior
communicating arteries,
and posterior cerebral
arteries
Position:
• lies in interpeduncular
fossa.
34. • The cranial nerves are a set of 12 paired nerves that arise
directly from the brain.
• The first two nerves (olfactory and optic) arise from
the cerebrum, whereas the remaining ten emerge from the
brainstem.
• The names of the cranial nerves relate to their function and they
are numerically identified in roman numerals (I-XII).
35. • They can arise from a specific part of the brainstem (midbrain, pons
or medulla), or from a junction between two parts:
• Midbrain – the trochlear nerve (IV) comes from the posterior side
of the midbrain. It has the longest intracranial length of all the
cranial nerves.
• Midbrain-pontine junction – oculomotor (III).
• Pons – trigeminal (V).
• Pontine-medulla junction – abducens, facial, vestibulocochlear
(VI-VIII).
• Medulla oblongata
– Posterior to the olive: glossopharyngeal, vagus, accessory (IX-XI).
– Anterior to the olive: hypoglossal (XII).
36. Name & Function
1. Olfactory nerve: Sense of smell.
2. Optic nerve: Ability to see.
3. Oculomotor nerve: Ability to move and blink your eyes.
4. Trochlear nerve: Ability to move your eyes up and down or back and forth.
5. Trigeminal nerve: Sensations in your face and cheeks, taste and jaw movements.
6. Abducens nerve: Ability to move your eyes.
7. Facial nerve: Facial expressions and sense of taste.
8. Auditory/vestibular nerve: Sense of hearing and balance.
9. Glossopharyngeal nerve: Ability to taste and swallow.
10. Vagus nerve: Digestion and heart rate.
11. Accessory nerve (or spinal accessory nerve): Shoulder and neck muscle movement.
12. Hypoglossal nerve: Ability to move your tongue.
37. • Cranial nerves I, II, and VIII are pure sensory nerves.
• Cranial nerves III, IV, VI, XI, and XII are pure motor
nerves.
• Cranial nerves V, VII, IX, and X are mixed sensory and
motor nerves.
