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Folds of Dura Mater brain neuroscience science and technology and references
- 1. Folds of DuraMater Dr.Yogeshwar N. Deshpande Assistant Professor Rachana Sharir RT Ayurved Mahavidyalaya,Akola
- 2. Objectives - Learnerswill able to explain following points- Dura Mater Falx Cerebri Falx cerebelli Tentorium Cerebelli Diaphragma sellae Attachments & related sinuses within the above folds
- 3. Dura Mater Outermostthickest & toughest membrane covering the brain There are 2 layers of Dura mater, Outer endosteal layer/endocranium Inner layer is meningeal layer- which surrounds the brain
- 4. Endocranium Continuous with theperiosteum lining outside the skull, through suture & Foramina , & also with the periosteal lining of orbit through the superior orbital fissure. (The periosteum is a membrane that covers the outer surface of all bones, except at the articular surfaces in the joint.)
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- 7. More about endocraniumis It provides the sheath for cranial nerves Its outer surface is adherent with the inner surface of cranial bones.
- 8. Meningeal layer It isinner layer of dura mater. It folds on it self to form partitions which divide the cranial cavity into different compartments, which lodge different parts of brain
- 9. Folds of Duramater Falx cerebri Falx cerebelli Tentorium Cerebelli Diaphragma sellae
- 11. Falx Cerebri It islarge sickle shaped fold of dura mater occupying the median longitudinal fissure between 2 cerebral hemispheres.
- 12. Anterior end isnarrow & attached to crista gelli, Posterior end is broad & attached along the median plane to upper surface of tentorium cerebelii
- 13. The crista galliis the upper part of the perpendicular plate of the ethmoid bone, which rises above the cribriform plate.
- 14. Margins & surfacesof falx cerebri Falx cerebri has 2 margins Upper margin is convex & attached to lips of the sagittal sulcus. Lower margin is concave & free It has 2 surfaces i.e. Right & left surface Each is joined to medial surface of corresponding cerebral hemisphere
- 15. Margins of falxcerebri
- 16. Venous Sinuses ofFalx cerebri What are venous sinuses Dural venous sinuses are venous channels located intracranially between the two layers of the dura mater (endosteal layer and meningeal layer).
- 17. 3 venous sinusesare present in relation to this fold. Superior sagittal sinus – lies along the upper margin Inferior sagittal sinus –lies along the lower margin & straight sinus- which lies along the line of attachment of falx to tentorium cerebelii.
- 18. Tentorium cerebelii Tentshape fold of Dura mater forms roof of posterior cranial fossa. Separates cerebellum from occipital lobes of cerebrum & divides the cranial cavity into supra tentorial & infra tentorial compartments. Posterior cranial fossa contains hind brain & lower part of mid brain
- 19. Margins of tentoriumcerebelii- 2 margins. Free margin & attached margin.
- 20. Free margin isU shaped & attached to anterior clinod process Anterior Clinoid Process-The posterior border of small wing of sphenoid, is smooth and rounded , the medial end of this border forms the anterior clinoid process
- 22. U Shaped freemargin bounds the tentorial notch which is occupied by mid brain & anterior part of superior vermis
- 23. Outer or attachedmargin is convex, posterolaterally is attached to lips of the transverse sulci on occipital bone. Antrolaterally- it is attached to superior border of petrous temporal bone & to the posterior clinoid process. Superior border of petrous temporal bone Anterior clinoid process Posterior clinoid process
- 24. Along with theattached margin, there are transverse sinus & superior petrosal venous sinuses
- 25. Free & attachedmargins cross each other near apex of petrous temporal bone .Anterior to the point of crossing there is trangular area which forms posterior part of roof of cavernous sinus
- 26. Surfaces of tentoriumcerebelii 2 surfaces are present Superior surface- convex & has slops on either sides To this surface falx cerebri is attached, in midline The straight sinus lies along the line of this attachmnet. It is attached to occipital lobe of cerebrum
- 28. Inferior surface oftentorium cerebelii It is concave & fits the convex superior surface of cerebellum Falx cerebelii is attached to its posterior part
- 29. Falx cerebelli Itis small sickle shaped fold of dura mater projecting forward into posterior cerebellar notch Base of this structure is attached to posterior part of inferior surface of tentorium cerebelii. Apex is divided into 2 parts which are lost on the sides of foramen magnum Anterior margin is concave & free
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- 31. The posterior marginis convex & attached to the internal occipital crest & encloses occipital sinus Internal occipital crest
- 32. Diaphragma sellae It issmall circular horizontal fold of dura mater forming roof of hypophyseal fossa
- 33. Anterior it attachedto tuberculum sellae Posteriorly it is attached to dorsum sellae On each side it is continuous with the dura mater of middle cranial fossa
- 34. It has centralaperture through which the stalk of the hypophysis cerebri passes Central aperture
- 35. Blood supply 1.Middle meningeal A. 2. Anterior ethmoidal, Posterior ethmoidal & opthalmic arteries 3. accessory meningeal & internal carotid 4. Meningeal branches of vertebral, occipital & ascending pharyngeal arteries.
- 36. Nerve supply Mostlyfrom opthalmic division of trigeminal nerve Anterior ethmoidal nerve Maxillary nerve Mandibular nerve Recurrent branches from 1st,2nd, 3rd cranial spinal nerves Meningeal branches of 9th & 10th cranial nerves.