Venous sinuses

1. Venous sinuses Dr.Saeed M ustafa

2. Cranial Meninges

3. 3 Meninges of the Spinal Cord Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spinal cord Spinal cord Pia mater Arachnoid mater Dura mater Dorsal root Dorsal root Spinal nerve Epidural space (a) (b) Ventral root Dorsal root ganglion Thoracic vertebra Spinal nerve Dorsal root ganglion Subarachnoid space Dorsal branch (dorsal ramus) Ventral branch (ventral ramus) Ventral root Epidural space Body of vertebra

4. CRANIAL MENINGES Dura : an inner ( meningeal ) layer and outer ( periosteal ) layer Most of the dura’s venous sinuses lie between the dural layers Dural layers are generally fused, except where they separate to provide space for the venous sinuses and where the inner layer forms septa between the brain portions Outer layer firmly attached to inner surface of cranial bones; inner layer continuous with spinal dura

5. Meninges: Dura Mater Reflections: Falx cerebri: Midline fold of dura mater extending between two cerebral hemispheres. Tentorium cerebelli: Dural fold located between cerebellum and occipital lobes of cerebral hemispheres.

6. Meninges: Dura Mater Reflections: Falx cerebelli : Dural fold between two cerebellar hemispheres. Diaphragma sellae Dural fold over hypophyseal fossa .

7. CRANIAL MENINGES CRANIAL MENINGES Arachnoid : Delicate avascular membrane covers the subarachnoid space Between the arachnoid and dura mater lies the subdural space Arachnoid granulations project into the superior sagittal sinus

8. Arachnoid granulations － project into sinuses of dura mater, serve as sites where cerebrospinal fluid diffuses into bloodstream

9. Circulation of cerebrospinal fluid CSF drains from lateral ventricle interventricular foramina third ventricle mesencephalic aqueduct fourth ventricle median and two lateral apertures subarachnoid space arachnoid granulations superior sagittal sinus vein

10. CRANIAL MENINGES Pia : Thin connective tissue membrane that covers the brain surface and extends into sulci and fissures and around blood vessels throughout the brain Beyond the end of the spinal cord continues as the filum terminale

11. Dural Nerve Supply Branches of trigeminal,vagus and 1 st 3 cervical nerves Sensitive to streching which produces the sensation of headache

12. Dural arterial supply Int. carotid artery Maxillary Ascending pharyngeal Occipital Vertebral *Middle meningeal artery

13. Intra cranial hemorrhage 1.Extra dural (middle meningeal artery) 2.Subdural ( sup.cerebral vein) 3.Subarachnoid (the circle of willis ) Blood stained csf 4.Cerebral ( lenticulostriate artery)

14. VENOUS DRAINAGE Venous drainage of the brain and coverings includes veins of the brain itself, dural venous sinuses, dura’s meningeal veins, and diploic veins Eventual cerebral venous drainage is the internal jugular vein Cerebral veins contain no valves

15. Vasculature: Venous Sinuses

16. Dural venous sinuses : Superior sagittal sinus: Lies along superior margin of falx cerebri . receives in its course the sup.cerebral vein Inferior sagittal sinus: Lies along inferior margin of falx cerebri . joins great cerebral vein

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18. Meninges: Dura Mater Dural venous sinuses: Straight sinus: Lies at intersection of falx cerebri and tentorium cerebelli. Confluence of sinuses: Common confluence of superior sagittal sinus and straight sinus.

19. Venous sinuses

20. Meninges: Dura Mater Dural venous sinuses: Transverse: Begins at confluence of sinuses. Extends along edges of tentorium cerebelli . Right receives blood from superior sagittal sinus. Left receives blood from straight sinus . receives sup.petrosal sinus,inf.cerebral n cerebellar veins n diploic veins

21. Meninges: Dura Mater Dural venous sinuses: Sigmoid: Continuation of straight sinus. “S”-shaped. Ends at jugular foramen: Joins internal jugular vein.

22. Superior n inferior petrosal sinuses Petrous part of temporal bone Sup.petrosal sinus drains the cavernous sinus into transverse sinus Inf.petrosal sinus drains the cavernous sinus into IJV

23. Vasculature: Venus Sinuses

24. The flowing of the blood in dural sinus Sup. sagittal sinus Inf. sagittal sinus Straight sinus Confluence of sinus Transverse sinus Cavernous sinus Sup. petrosal sinus Inf. petrosal sinus Internal jugular vein Sigmoid sinus

25. Cavernous sinus Middle cranial fossa Extends from Sup.orbital fissure to petrous part of temporal bone Tributaries Sup.n inf.ophthalmic veins,cerebral veins,the sphenoparietal sinus n the central vein of retina Drains Posteriorly into sup n inf petrosal sinuses and inferiorly into pterygoid venous plexus

26. Cavernous sinus Position : lies on each side of sella turcica Relations of cavernous sinus: Internal carotid artery and abducent nerve run through the sinus Oculomotor and trochlear nerves and ophthalmic and maxillary divisions of trigeminal nerve lie in the lateral wall of the sinus

27. Veins of brain Superficial cerebral veins Drain blood from cortex and subcortical medullary substance and empty into adjacent sinuses of dura mater

28. Veins of brain Deep cerebral veins : drain deeper parts of hemispheres, basal nuclei, internal capsule, diencephalon and choroid plexus, ultimately form great cerebral vein which enter straight sinus

29. Thanku