The brain and spinal cord have three coverings or meninges - the dura mater, arachnoid mater, and pia mater. The dura mater forms the outermost and toughest covering. Between the arachnoid mater and pia mater lies the subarachnoid space, which contains cerebrospinal fluid. The cerebrospinal fluid circulates through the ventricles and central canal before entering the subarachnoid space through openings at the base of the brain. It is then reabsorbed into the venous system through arachnoid villi. The meninges provide protection to the brain and spinal cord and allow for circulation of cerebrospinal fluid.

1. LECTURE NOTES IN ANATOMY OF
THE BRAIN

2. CHAPTER 1
COVERINGS OF THE BRAIN AND
SPINAL CORD

3. CHAPTER 1- MENINGES OF THE BRAIN AND SPINAL CORD
Brain is situated with in the cranial cavitIts coverings are Duramater, Arachnoid mater and Pia
mater. Dura mater of the brain is made up of two layers- outer endosteal and inner meningeal
layer. Dural venous sinuses are enclosed with in two layers of duramater.Duramater sends
processes to support the brain.
While dura ensheaths the brain, it is lined on its inner surface by a flimsy .delicate covering
called Arachnoid maQer. The innermost covering is the piamater which closely lines the surface
of the brain. Blood vessels lie on the surface of the piamater . The subarachnoid space is
between Arachnoid and Pia mater. Over the irregular surfaces of the brain the pia and arachnoi
are widely separated from each other and these spaces are known as subarachnoid cisterns

4. CHAPTER 1- MENINGES OF THE BRAIN AND SPINAL CORD
Cerebro spinal fluid circulates in the subarachnoid space. It is formed by the chroid plexesus ( arterial end) present within
the ventricles. It circulates in the central canal of the spinal cord and comes to the subarachoid space of brain and spinal
cord through three small openings-central foramen of Magendie and two lateral foraminae of Luschka.CSF is poured back
into the venous system by arachnoi vlli which protrude into the venous sinuses , It is a conVnuous process
Subdural space—capillary interval between dura & arachnoid
Subdural hematoma—pressure symptoms start immediately.-
more common. Superior cerebral vein rupture and bleed& lead
to this Subdural hematoma –Pressure symptoms start immediately
Epidural space –
Brain- Meningeal vessels
Spinal cord –Dural sac, spinal nerve roots , plexus of veins, spinal arteries ,lymphaVcs and fat. Local anestheVc which
exerts its effect on the spinal nerve root may be injected into this space.Epidural hematoma –Lucid internal .First face is
involved .Pressure symptoms delayed

5. APPLIED ANATOMY-Hydrocephalus
• Abnormal raise in volume of C.S.F
• Blockage of Foraminae,Congenital septum ,Adhesions due to meningiVs
displacement due to tumour (ependymomas)cardiac irregulariVes, Tachycardia,
Irregular respiraVon, Vasomotor disturbance
CHAPTER 1- MENINGES OF THE BRAIN AND SPINAL CORD