Cranial meninges

Cranial meninges

1. Cranial meninges Rajasri Manimaran Group 2

2. Protection of the Brain The Skull Cranial meninges Cerebrospinal fluid Blood brain barrier

3. The Meninges

4. 1. Dura Mater - Composed of two layers: a) Periosteal – outer layer, attaches to bone. b) Meningeal – inner layer, closer to brain . Cranial Meninges - 3 layer protective membrane Two layers fused, except to enclose the dural sinuses 3. Pia Mater - delicate, follows convolutions. 2. Arachnoid Layer - ‘spider’ web like .

5. Coronal section of the upper part of the head Endosteal layer Meningeal layer They are closely united except along certain lines; they are separated to form venous sinuses Superior sagittal sinus (Dural venous sinus) Dura mater Subdural space

6. Sagittal section showing the duramater 1) Falx cerebri 2) Tentorium cerebelli 3) Falx cerebelli 4) Diaphragma sellae

7. Dural Nerve Supply Branches of the trigeminal, vagus , and first three cervical nerves and branches from the sympathetic system pass to the dura. The dura is sensitive to stretching, which produces the sensation of headache.

8. Dural blood supply The  middle meningeal artery  supplies most of the blood for the dura mater, though the meningeal branches of the  posterior  and  anterior ethmoidal artery  also contribute.

9. Arachnoid mater

10. 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.

11. Subaracnoid space Relatively narrow over the surface of cerebral hemisphere, but sometimes becomes much wider in areas at the base of the brain, the widest space is called subarachnoid cisterns .

12. Median sagittal section to show the subarachnoid cisterns & circulation of CSF Superior cistern Interpeduncular cistern Cerebellomedullary cistern Chiasmatic cistern Pontine cistern

13. Pia mater Pia mater functions to cover and protect the  central nervous system  (CNS), to protect the blood vessels and enclose the venous sinuses near the CNS, to contain the cerebrospinal fluid (CSF) and to form partitions with the skull. The CSF, pia mater, and other layers of the meninges work together as a protection device for the brain, with the CSF often referred to as the fourth layer of the meninges .

14. Pathology There are three types of  hemorrhage  involving the meninges : An  epidural hematoma  arise after an accident or spontaneously A  subdural hematoma  is a  hematoma  (collection of blood) located in a separation of the  arachnoid  from the  dura mater . The small veins that connect the  dura mater  and the  arachnoid  are torn, usually during an accident, and blood leaks into this area A  subarachnoid hemorrhage  is acute bleeding under the arachnoid ; it may occur spontaneously or as a result of trauma.

15. Other medical conditions that affect the meninges include  meningitis  (usually from  fungal ,  bacterial , or  viral   infection ) and  meningiomas  that arise from the meninges , or from  meningeal carcinomatoses  ( tumors ) that form elsewhere in the body and  metastasize  to the meninges .

16. Cranial venous sinuses The  dural venous sinuses  (also called  dural sinuses ,  cerebral sinuses , or  cranial sinuses ) are  venous channels found between layers of  dura mater  in the  brain . They receive  blood  from internal and external  veins  of the brain, receive  cerebrospinal fluid  (CSF) from the  subarachnoid space , and ultimately empty into the  internal jugular vein .

17. Name Drains to Inferior sagittal sinus Straight sinus Superior sagittal sinus Typically becomes right transverse sinus or confluence of sinuses Straight sinus Typically becomes left transverse sinus or confluence of sinuses Occipital sinus Confluence of sinuses Confluence of sinuses Right and Left transverse sinuses Sphenoparietal sinuses Cavernous sinuses Cavernous sinuses Superior and inferior petrosal sinuses Superior petrosal sinus Transverse sinuses Transverse sinuses Sigmoid sinus Inferior petrosal sinus Sigmoid sinus Sigmoid sinuses Internal jugular vein

18. ARTERIES to specific brain areas Corpus striatum Middle & lateral striate Anterior & Middle cerebral artery Internal capsule Thalamus PComA , basilar, PCA Midbrain PCA, supCerebellarA, basilar Pons Basilar, Ant, inf, supCerebellarA, Medulla oblongata Vertebral, ASA,PSA,PICA, basilar Cerebellum supCerebellar , AICA,PICA

19. Blood Supply of The Brain VERTEBRAL Basilar Posterior cerebral artery INTERNAL CAROTID Middle cerebral Anterior cerebral Anterior communicating artery Posterior communicating artery CIRCLE OF WILLIS

20. Subarachnoid hemorrhage

21. 6/8/2013 © 2009, American Heart Association. All rights reserved. Aneurysm

22. symptoms Headache (sudden onset, greater severity) Nausea and vomitting Loss or impairment of consciousness (may progress to coma and death) Confusion and irritability Meningial irritation and nuchal rigidity (stiff neck) Focal neurological deficits (may indicate site of lesions) .

23. Differential diagnosis Meningitis Migraine Intracerebral hemorrhage Ischemic stroke

24. Grade Signs and symptoms Survival 1 Asymptomatic  or minimal headache and slight neck stiffness 70% 2 Moderate to severe headache; neck stiffness; no  neurologic  deficit except  cranial nerve   plasy 60% 3 Drowsy ; minimal neurologic deficit 50% 4 Stuporous ; moderate to severe hemiparesis ; possibly early  decerebrate rigidity  and vegetative disturbances 20% 5 Deep coma;  decerebrate rigidity ;  moribund 10% Hunt and H ess classification

25. Treatment Stabilizing patient. Prevention of rebleeding by obliterating the bleeding source. prevention of a phenomenon known as  vasospasm and, prevention and treatment of complications.

26. Preventing Re-bleeding Up to 14% of SAH patients may experience re-bleeding within 2 hours of the initial hemorrhage Re-bleeding was more common in those with a systolic blood pressure >160mm Hg Anti- fibrinolytic therapy may reduce re-bleeding but has not been shown to improve outcomes 6/8/2013 © 2009, American Heart Association. All rights reserved.

27. Surgical and Endovascular Management of SAH Surgery – clip aneurysm base Endovascular – coiling Should be performed within 2 days of hemorrhage. 6/8/2013 © 2009, American Heart Association. All rights reserved.

28. 6/8/2013 © 2009, American Heart Association. All rights reserved. Clipping

29. Left image arrow - Angio with Large aneurysm Right image arrow – Angio showing aneurysm post clipping 6/8/2013 © 2009, American Heart Association. All rights reserved. Angio Image Courtsey : The University of Texas Health Science Center at San Antonio – Department of Neurosurgery

30. Surgical and Endovascular Management of SAH Combined morbidity and mortality was significantly greater in surgically treated patients than in those treated with endovascular techniques (30.9% vs. 23.5%; absolute risk reduction 7.4%) During the short follow-up period, the re-bleeding rate for coiling was 2.9% versus 0.9% for surgery There have been no randomized comparisons of coiling versus clipping for unruptured aneurysms 6/8/2013 © 2009, American Heart Association. All rights reserved.

31. 6/8/2013 © 2009, American Heart Association. All rights reserved. Coiling

32. Coil system embolization : immediate result 6/8/2013 © 2009, American Heart Association. All rights reserved. Angio showing large ICA aneurysm Same aneurysm - Post GDC Coiling Angio Image Courtsey : The University of Texas Health Science Center at San Antonio – Department of Neurosurgery

33. Preventing vasospasm The use of  calcium channel blockers , thought to be able to prevent the spasm of blood vessels by preventing  calcium  from entering smooth muscle cells, has been proposed for the prevention of vasospasm. The oral calcium channel blocker  nimodipine  improves outcome if administered between the fourth and twenty-first day after the hemorrhage .

34. Preventing other complications If medication don’t help, then   angiography may be attempted to identify the sites of vasospasms and administer vasodilator  medication (drugs that relax the blood vessel wall) directly into the artery.  Angioplasty  (opening the constricted area with a balloon) may also be performed .

35. Summary and Conclusions The current standard of practice calls for microsurgical clipping or endovascular coiling of the aneurysm neck whenever possible Treatment morbidity is determined by numerous factors, including patient , aneurysm , and institutional factors 6/8/2013 © 2009, American Heart Association. All rights reserved.

36. Summary and Conclusions Favorable outcomes are more likely in institutions that treat high volumes of patients with SAH, in institutions that offer endovascular services, and in selected patients whose aneurysms are coiled rather than clipped Optimal treatment requires availability of both experienced cerebrovascular surgeons and endovascular surgeons working in a collaborative effort to evaluate each case of SAH 6/8/2013 © 2009, American Heart Association. All rights reserved.