2. Embryology OF Ventricles Closure of neural tube by 28 days of gestation. Certain portions of central lumen expand to form basic pattern of ventricular sytem. forebrain midbrain hindbrain lateral 3rd cerebral aqueduct 4th

3. The fluid-filled cavities in the developing neural tube of the embryo form the ventricles of the mature brain.

4. Ventricles The ventricular surfaces are lined by a single layer of ependymal cells with tight junctions. Ventricles are filled with cerebrospinal fluid (CSF) produced by the choroid plexus. ant body in po

5. Ventricles Of Brain Lateral Ventricle lateral ventricles are the largest of the ventricles. They are irregular in shape. Each consists of a central part, with anterior, posterior and inferior horns.

6. Anterior Horn of Lateral Ventricle Anterior Horn Anterior Horn is anterior to the IVF. Roof and anterior border are formed by the corpus callosum, Medial wall is Formed by the by the septum pellucidum. The floor is formed by the head of the caudate nucleus

7. Body of lateral Ventricle Extends from the splenium of the corpus callosum to the IVF. Medial Wall is Formed by the posterior part of the septum pellucidum. Floor Is formed by the parts of the caudate nucleus, thalamus, choroid plexus and fornix.

8. Inferior Horn of Lateral ventricle It traverses the temporal lobe. Its roof is formed by the white substance of the cerebral hemisphere. Along the medial border is the striaterminalis and the tail of the caudate nucleus. The amygdaloid nucleus bulges into the terminal part of the inferior horn. The floor and the medial wall are formed by the fimbriae, the hippocampus and the collateral eminence.

9. Inferior Horn of Lateral ventricle

10. Third Ventricle The third Ventricle The third ventricle is a narrow cavity along the midline superior to the hypothalamus and between the right and left halves of the thalamus

11. The Third Ventricle It possesses a roof, a floor and four walls: anterior, posterior and two lateral. The roof is formed by the tela choroidea. The floor is made up of the optic chiasm, the tuber cinereum and the infundibulum, the mamilary bodies, the posterior perforated substance and the upermost part of the mesencephalic tegmentum. The anterior wall is the delicate lamina terminalis. The short posterior wall is formed by the stalk of the pineal gland and the habenular commissures. The lateral walls are formed mainly by the medial surfaces of the 2 thalami. The lower lateral wall and the floor of the ventricle are formed by the hypothalamus and subthalamus.

12. Fourth Ventricle The fourth ventricle is a cavity which lies posterior to the pons and upper half of the medulla oblongata and anterior to the cerebellum. It is continuous with the cerebral aqueduct (mesencephalic or Sylvius) above and the central canal of the spinal cord in the lower half of the medulla. On each size, a narrow prolongation, the lateral recess, projects around the brainstem; its lateral aperture (forame of Luschka) lies below the cerebellar flocculus.

13. Fourth Ventricle The fourth ventricle has lateral boundaries, a roof and a floor. The lateral boundaries are formed on each side by the superior cerebellar peduncle, the inferior cerebellar peduncle and the cuneate and gracile tubercles.

14. Fourth Ventricle Roof of the fourth ventricle - Formed by thin laminae of white matter. The lower has a median aperture (foramen of Magendie); cerebrospinal fluid escapes through this opening and lateral apertures into the subarachnoid space. Because these are the only communications between the ventricular and subarachnoid spaces, their blockage can produce one type of hydrocephalus. The floor of the fourth ventricle, also known as rhomboid fossa, is formed by the dorsal surfaces of the pons and medulla oblongata.

15. cerebrospinal fluid circulation clear & colorless water-like fluid formed by choroid plexus – mainly in lateral ventricles (& to lesser degree in 3rd & 4th ventricles) formation of CSF complex – includes both passive filtration & active secretary mechanisms

17. CSF circulation CSF produced in lateral ventricles – enters third ventricle through interventricular foramen flows through cerebral aqueduct – into fourth ventricle from fourth ventricle it reaches the subarachnoid space

19. CSF circulation CSF enters subarachnoid space via three openings: – median aperture (posterior medullary velum) – two lateral apertures (lateral recesses of fourth ventricle)

20. CSF circulation collections of microscopic arachnoid villi form macroscopic elevations (arachnoid granulations) that protrude into the lateral expansions of the superior sagittal sinus through openings in the dura flow of CSF is fairly rapid

22. CSF circulation total volume of CSF in the ventricular system & subarachnoid space is only about 125 ml but it is estimated that about four times that amount (~500 ml) is formed during a 24 hr period a small amount of CSF seeps down around the spinal cord

23. Normal Brain

24. Normal Ventricles

25. Hydrocephalus

27. Normal ventricles and hydrocephalus 26

28. Case presentation CC - A 9 month old infant is brought to his family physician because his parents are worried that the child’s head appears too large. HPI- The mother had an apparently uneventful pregnancy and delivery. At birth the child’s body weight and head circumference were at 65 th percentile (Normal)

29. Clinical Case cont.. PE- Lethargic and irritable; anterior fontanellae bulging; when pressed slightly it immediately pops back; head circumference enlarged. Lab-RPR( Rapid plasma reagin) in mother –ve (For syphilis).

30. Case Presentation 29 year old woman is 32 weeks pregnant She has complained of intermittent headache and nausea for the last 16 weeks Previous ER examinations have been normal She collapses outside ER after 3rd visit and is brought in comatose with extensor posturing and an dilated left pupil

31. HYDROCEPHALUS

32. DEFINITION: DIVERSE GROUP OF CONDITIONS WHICH RESULT FROM IMPAIRED CIRCULATION AND RESORPTION OF CSF.

33. CSF FORMATION CSF IS FORMED BY THE CHOROID PLEXUS. NORMAL CSF PRODUCTION: 20 ml/h.

34. TYPES OF HYDROCEPHALUS OBSTRUCTIVE OR NON-COMMUNICATING (OBSTRUCTION WITHIN THE VENTRICULAR SYSTEM) NON OBSTRUCTIVE OR COMMUNICATING (MALFUNCTION OF ARACHNOID VILLI)

35. CAUSES OF HYDROCEPHALUS LESIONS OR MALFORMATIONS OF THE POSTERIOR FOSSA – CHIARI MALFORMATION – DANDY- WALKER SYNDROME – TUMORS IVH MENINGITIS: PNEUMOCOCCAL, TB INTRAUTERINE INFECTIONS

36. PATHOLOGY AQUEDUCTAL STENOSIS: – ABNORMALLY NARROW AQUEDUCTUS OF SYLVIUS. AQUEDUCTAL GLIOSIS: – BRISK GLIAL RESPONSE OF EPENDIMAL LINING

37. CHIARI MALFORMATION TYPE I: – DISPLACEMENT OF CEREBELLAR TONSILS INTO THE CERVICAL CANAL. – GIVES SYMPTOMS IN ADOLESCENCE OR ADULT LIFE. (HEADACHE, NECK PAIN) – NO HYDROCEPHALUS.

38. CHIARI MALFORMATION TYPE II : – PROGRESSIVE HYDROCEPHALUS AND MYELOMENINGOCELE. – ELONGATION OF THE 4TH VENTRICLE. – DISPLACEMENT OF INFERIOR VERMIS, PONS, AND MEDULLA INTO CERVICAL CANAL

39. DANDY-WALKER SYNDROME CYSTIC EXPANSION OF THE 4TH VENTRICLE IN THE POSTERIOR FOSSA. DEVELOPMENTAL FAILURE OF ROOF OF 4TH VENTRICLE DURING EMBRYOGENESIS. 90 % HAVE HYDROCEPHALUS PROMINENT OCCIPUT

40. IVH DEFINITION: – BLEEDING IN SUBEPENDIMAL GERMINAL MATRIX WITH/WITHOUT EXTENSION INTO VENTRICLES AND BRAIN PARENCHYMA INCIDENCE: – IN PREMATURES 25 - 40 %

41. CLINICAL MANIFESTATIONS SYMPTOMS: – IRRITABILITY – POOR FEED – LETHARGY – VOMITING – IN OLDER PATIENTS: HEADACHE CHANGES IN PERSONALITY ACADEMIC DETERIORATION

42. CLINICAL MANIFESTATIONS SIGNS: – ANTERIOR FONTANEL WIDE OPEN AND BULGING, INCREASED HEAD CIRC. – DILATED SCALP VEINS – SETTING SUN SIGN – BRISK TENDON REFLEXES, SPASTICITY – CLONUS, BABINSKY – MACEWEN SIGN “CRACKED POT” – PROMINENT OCCIPUT (DANDY-WALKER)

43. IMAGING STUDIES X-RAY PLAIN FILMS: – SEPARATION OF SUTURES – EROSION OF POSTERIOR CLINOIDS – INCREASED CONVOLUTIONAL MARKINGS (BEATEN SILVER APPEAREANCE) ULTRASOUND CT SCAN MRI