Csf production,circulation & absorption

1. CSF PRODUCTION, CIRCULATION &ABSORPTION LECTURE BY DR. ANSARI CHAIRPERSON & PROF. OF ANATOMY RAK COLLEGE OF MEDICAL SCIENCES & RAK COLLEGE OF DENTAL SCIENCES Wednesday, May 15, 2013 1

2. A 9 year old boy was brought to his GP by his parents who noted that he was having difficulty with his balance and was complaining of head aches. He was referred to the neurosurgical unit and a CT scan was perform of his head region. This showed the presence of dilated lateral and III ventricles with a normal IV ventricle. There was effacement of the overlying cortical sulci in the brain and a diagnosis of Hydrocephalus was made. MRI showed the cerebral aqueduct was stenosed . The boy subsequently had a III ventriculostomy performed, and his symptoms resolved rapidly . Wednesday, May 15, 2013 2

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4. C.S.F Circulation involves Lateral ventricle. III ventricle. Cerebral aqueduct. IVventricle . Subarachnoid cisterns Subarachnoid spaces Wednesday, May 15, 2013 4

5. Sub arachnoid cisterns & spaces The major cisterns are:- 1) Cisterna interpeduncularis 2) Cisterna ambiens 3) Cisterna magna 4) Cistern of the lateral sulcus 5) Cisterna pontis 6 ) Subarachnoid spaces Wednesday, May 15, 2013 5

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8. The arachnoid villi & granulations Are the structures that drain the excess amount of CSF into the circulatory system/Dural venous sinuses. These are the safety valve that opens up and drain into the superior Sagittal sinus. From the ventricles the CSF comes out into the subarachnoid sinuses through 3 apertures, Foramen of Magendie & foramina of Lusaka Wednesday, May 15, 2013 8

9. Wednesday, May 15, 2013 9 The CSF is drained in to the superior sagittal sinus through the arachnoid villi and granulations

10. Humans produce 500 ml of CSF daily The total CSF volume is only 1/3 of the daily production . Most of the 500 ml of CSF is produced in the choroid plexuses in the four brain ventricles, and the remaining is produced across the blood-brain barrier. The CSF passes from the lateral ventricles (I and II) through the foramen of Monroe into the third ventricle (III), through the aqueduct of Sylvius, the fourth ventricle (IV), and out into the subarachnoid space through the foramina Lushka & Magendie . Wednesday, May 15, 2013 10

11. (18) foramina of L ushka Wednesday, May 15, 2013 11

12. Foramen of Monro/interventricular foramen (12) Wednesday, May 15, 2013 12

13. Cast of the ventricles of brain Anterior horn of lateral ventricle Body of lateral ventricle Posterior horn of lateral ventricle Inferior horn of lateral ventricle Third ventricle Fourth ventricle Interventricular foramen Cerebral aqueduct Wednesday, May 15, 2013 13

14. The lateral ventricles Situated in the cerebral hemispheres, it has a body, an anterior horn in the frontal pole, posterior horn in the occipital pole &inferior horn in the temporal pole. The two lateral ventricles are interconnected by interventricular foramen and it also communicates with the III ventricle. All ventricles are lined by ependyma. The choroid plexus are formed by a dual layer of ependyma invaded by bunch of capillaries. Wednesday, May 15, 2013 14

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16. Tela choroidea (7) is a double fold of Pia mater entering into the choroid fissure and forming the organs for CSF formation along with the choroid plexus Wednesday, May 15, 2013 16

17. Wednesday, May 15, 2013 17 Tela choroidea

18. The duct of Sylvius /Cerebral aqueduct forms the cavity of midbrain Wednesday, May 15, 2013 18

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20. Roof of IV ventricle formed by cerebellum and superior cerebellar peduncles and superior medullary velum Wednesday, May 15, 2013 20

21. The fifth ventricle & terminal ventricle The central canal expanding at the level of filum terminale, of conus medullaris, is the terminal ventricle. The fifth ventricle is the median cleft between the two laminae of the brain's septum pellucidum (cavum septum pellucidum ). The CSF is getting emptied / drained into the dural venous sinuses through the arachnoid villi and granulations. Wednesday, May 15, 2013 21

22. Cavum Septum pellucidum Wednesday, May 15, 2013 22

23. Wednesday, May 15, 2013 23 A sagittal section of the brain showing the ventricles

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25. III Ventricle It lies below the lateral ventricles. It is a cavity of the diencephalon. In the roof there is choroid plexus, that produce CSF. Superiorly it communicates with the two lateral ventricles through the interventricular foramen. Inferiorly it communicates with the IV ventricle through the cerebral aqueduct. The lateral wall is formed by thalamus and hypothalamus. The two thalami are annexed by interthalamic adhesion. Wednesday, May 15, 2013 25

26. Structures in the lateral wall of III ventricle Thalamus Hypothalamus Midbrain Pons Interthalamic adhesion Anterior commissure Optic chiasma Mammillary body Pineal body Tectum of midbrain Lamina terminalis Interventricular foramen Wednesday, May 15, 2013 26

27. IV Ventricle It is a cavity of the rhombencephalon. It has a roof and floor. The floor is formed by two parts, medullary & pontine part. Hypoglossal nucleus, vagal nucleus, trigeminal nucleus, glossopharyngeal nucleus, auditory nuclei and facial and abducent nuclei are located in the floor. Wednesday, May 15, 2013 27

28. Applied anatomy of ventricles of brain Hydrocephalus Anencephaly Spina bifida Meningitis Encephalitis Wednesday, May 15, 2013 28

29. Wednesday, May 15, 2013 29 Imaging study showing enlarged cavities of brain due to hydocephalous