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Meninges covering the brain include three layers from outside in:
  1. Dura mater (pachymeninx),
  2. Arachnoid mater, and
  3. Pia mater. Arachnoid and pia maters together are known as leptomeninges.

Dura mater (pachymeninx)


Dura mater is the tough test and thickest membrane covering the brain. It is divisible into outer endosteal layer or endocranium (covering inner surface of skull bones) and inner meningeal layer. Inner meningeal layer is folded on itself at places dividing the cranial cavity into intercommunicating compartments which lodge different parts of brain

  1. Falx cerebri: It is a large sickle shaped fold projecting into median longitudinal fissure between two cerebral hemisphere. It contains superior saggital sinus (along lower concave free margin), and straight sinus (along line of attachment of falx cerebri to tentorium cerebelli).
  2. Tentorium cerebelli: It roofs the posterior cranial fossa separating cerebellum from occipital lobes of cerebrum. It divides the cranial cavity into supratentorial and infratentorial spaces. Trigeminal (Meckel's) cave is a recess of dura mater which is formed by evagination of inferior layer of tentorium over trigeminal impression on the petrous temporal bone. It contains trigeminal ganglion. Tentorium cerebelli encloses transverse sinus and superior petrosal sinuses.
  3. Falx cerebelli: It is small sickles shaped fold projecting forwards in between two cerebellar hemispheres. It encloses occipital sinus.
  4. Diaphragma sellae: It roofs the sella turcica which lodges the pituitary gland. It encloses anterior and posterior intercavernous sinus.


Nerve supply of Dura mater:-

  1. Anterior cranial fossa:
    1. Anterior and posterior ethmoidal nerves, branches of ophthalmic division, of trigeminal (V) nerve, are main supply;
    2. Nerves meningus medius, which is a meningeal branch of maxillary nerve;
    3. Nervus spinosus, which is a meningeal branch of mandibular nerve.
  2. Middle cranial fossa:
    1. Maxillary nerve (nerves meningus medius) in anterior half;
    2. Mandibular nerve (nervus spinosus) and trigeminal ganglion in posterior half.  
  3. Posterior cranial fossa :
    1. Upper three (C1-C3) spinal nerves;
    2. Vagus and hypoglossal through hypoglossal) nerves; and possibly
    3. From facial and glossopharyngeal nerves.

Arterial supply is as follows:-

  1. The anterior cranial fossa and the dural lining are supplied by meningeal branches of the anterior ethmoidal, posterior ethmoidal and ophthalmic arteries.
  2. The middle cranial fossa is supplied by the middle meningeal, accessory meningeal, and internal carotid and by meningeal branches of the ascending pharyngeal artery.
  3. The posterior cranial fossa is supplied by meningeal branches of the vertebral, occipital and ascending pharyng arteries.

Arachnoid mater


It is a thin nonvascular membrane loosely covering brain and bridging the various irregularities on its surface as arachnoid mater surrounds the brain without dipping into sulci.


Pia meter


It is a delicate highly vascular membrane closely investing brain, dipping into various sulci and other irregularities of its surface. It provides sheaths for cranial nerve (merging with epineurium around them) and perivascular sheaths for blood vessels penetrating the brain. In ventricles of brain, the pia mater encloses tufts of capillaries to form tela choroidae. Such pia mater lined by secretary ependyma forms choroid plexus.


Subarachnoid cisterns


Subarachnoid space containing CSF is dilated in certain locations to form cisterns.







1. Cerebellomedullary cistern (cisterna magna used for cisternal puncture)

Between caudal surface of cerebellum and dorsal surface of medulla (largest).

Receives CSF from IV ventricle through foramen Magendie and communicates with spinal subarachnoid space

2. Cisterna pontis

Anterior to pons and medulla (upper part).

Basilar and vertebral artery

3. Cisterna basalis or interpeduncularis

Overlies interpeduncular fossa

Arterial circle of Willis.

4. Cerebellopontine cistern

Lateral to pons, anterior to cerebellum

V, VI, & VII nerves, labyrinthine branch of basilar artery.

5. Cisterna ambiens

Between splenium of corpus callosum and tectum (midbrain).

Great cerebral vein of Galen

6. Chiasmatic cistern

Below and in front of optic chiasma


7. Cisterna Sylvius

Within lateral sulcus

Middle cerebral artery, superficial and deep middle cerebral vein.

8. Peri callosal cistern

Above corpus callosum

Anterior cerebral artery.


Parts of brain


Brain is divided into three parts:

  1. Forebrain (prosencephalon),
  2. Midbrain (mesencephalon) and
  3. Hindbrain (rhombencephalon).

Parts of Brain




1. Forebrain (prosencephalon)

A. Telencephalon (cerebrum), made up to two cerebral hemispheres and the median part in front of the interventricular foramen.

B. Diencephalon (thalamencephalon), hidden by the cerebrum, consists of :

i) Thalamus

ii) Hypothalamus

iii) Metathalamus, including the medial and lateral geniculate bodies, 

iv) Epithalamus, including the pineal body, habenular trigone posterior commissure

v) Subthalamus

Lateral ventricle





2. Midbrain (mesencephalon)

Crus cerebri, substantia nigra, tegmentum, tectum, from before backwards.

Cerebral aqueduct


3. Hindbrain (rhombencephalon)

A. Metencephalon made up of pons and cerebellum.

B. Myelencephalon or medulla oblongata.



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