The document summarizes the dural venous sinuses and cavernous sinus. It describes that the dura mater contains venous sinuses that drain blood from the brain. The cavernous sinus is located at the base of the skull and contains several cranial nerves. It communicates with other sinuses and veins to drain blood from the brain into the internal jugular vein. The document provides details on the locations and contents of the various dural venous sinuses, including the superior sagittal sinus and cavernous sinus.

1. Dural Venous Sinuses and
Cavernous sinus
Dr. Vishwajit Deshmukh

4. Coverings of Brain

5. • Three concentric membranes, the meninges, envelop the brain and spinal cord. They
provide support and protection for the delicate tissues they surround.
• The individual layers, in order from outside to inside, are the dura mater
(pachymeninx), arachnoid mater and pia mater (Leptomeninx).
• The dura is an opaque, tough, fibrous coat which incompletely divides the cranial cavity
into compartments and accommodates the dural venous sinuses.
• The arachnoid is much thinner than the dura and is mostly translucent. It surrounds the
brain loosely, spanning over depressions and concavities.
• The pia mater is a transparent, microscopically thin, membrane which follows the
contours of the brain and is closely adherent to its surface.
Coverings of Brain

6. • The dura is separated from the arachnoid by a narrow subdural space.
• The arachnoid is separated from the pia by the subarachnoid space, which varies
greatly in depth; the larger expanses are termed subarachnoid cisterns.
• The subarachnoid space contains cerebrospinal fluid, CSF, which is secreted by the
choroid plexuses of the cerebroventricular system.
• CSF circulates within the subarachnoid space and is reabsorbed into the venous
system through arachnoid villi and granulations associated with the dural venous
sinuses.
Meninges of Brain

7. Subdural And Subarachnoid Space

8. Arachnoid Granulations

9. • Dura mater is thick, dense and fibrous. It is predominantly acellular, and consists
mainly of densely packed fascicles of collagen fibres arranged in laminae.
• The cranial dura, which lines the cranial cavity, differs from the spinal dura mainly in its
relationship to the surrounding bones.
• It has an inner, or meningeal, layer and an outer, or endosteal, layer.
• These layers are united except where they separate to enclose the venous sinuses that
drain blood from the brain.
• There is little histological difference between the endosteal and meningeal layers. Both
contain fibroblasts, and the endosteal layer also contains osteoblasts.
• The dura mater adheres to the internal surfaces of the cranial bones, particularly at the
sutures, the cranial base and around the foramen magnum
Duramater

11. • The endosteal layer of the dura is continuous with the pericranium through the cranial
sutures and foramina and with the orbital periosteum through the superior orbital
fissure.
• The meningeal layer provides tubular sheaths for the cranial nerves as they pass out
through the cranial foramina, and these sheaths fuse with the epineurium as the
nerves emerge from the skull.
• The dural sheath of the optic nerve is continuous with the ocular sclera.
• The dura fuses with the adventitia of major vessels, such as the internal carotid and
vertebral arteries, at sites where they pierce it to enter the cranial cavity.
• An extradural haematoma therefore acts as a rapidly expanding intracranial mass
lesion: it is a classic medical emergency that requires immediate diagnosis and
surgery.
Extensions of Duramater

13. Extradural Hematoma

14. Dural Partitions
• The meningeal layer of the dura is reflected inwards to form four septa, namely the falx
cerebri, falx cerebelli, diaphragma sellae and tentorium cerebelli that partially divide the
cranial cavity into compartments.
• Falx cerebri
The falx cerebri is a strong, crescent-shaped sheet that lies in the sagittal plane and
occupies the longitudinal fissure between the two cerebral hemispheres
• Falx Cerebelli
The falx cerebelli is a small midline fold of dura mater that lies below the tentorium
cerebelli and projects forward into the posterior cerebellar notch between the
cerebellar hemispheres
• Diaphramatic Sella
The diaphragma sellae is a small, circular, horizontal sheet of dura mater.
It forms a roof over the sella turcica and often almost completely covers the pituitary
gland.
The infundibulum and pituitary stalk pass into the pituitary fossa through a central
opening in the diaphragma.

17. Tentorium Cerebelli

18. • Dural venous sinuses form a complex network of venous channels which drain blood
from the brain and cranial bones
• They lie between the endosteal and meningeal layers of dura mater, are lined by
endothelium, have no valves, and their walls are devoid of muscular tissue.
Dural Venous Sinuses

19. Dural Venous Sinuses
Unpaired sinuses
• Superior Sagittal Sinus
• Inferior sagittal sinus
• Straight sinus
• Occipital Sinus
• Anterior cavernous sinus
• Posterior cavernous sinus
Paired Sinuses
• Sphenoparietal sinus
• Cavernous sinus
• Superior petrosal sinus
• Inferior petrosal sinus
• Transverse sinus
• Sigmoid Sinus

21. • The superior sagittal sinus runs in the
attached convex margin of the falx cerebri.
• It grooves the internal surface of the
frontal bone, the adjacent margins of the
two parietal bones and the squamous part
of the occipital bone.
• It begins near the crista galli, a few
millimetres posterior to the foramen
caecum, and receives primary tributaries
from cortical veins of the frontal lobes, the
ascending frontal veins
Superior Sagittal Sinus

26. Cavernous Sinuses
• The extension is from the superior orbital fissure to the apex of the petrous temporal
bone, with an average length of 2 cm and width of 1 cm

27. Cavernous Sinuses Contents
• The abducens nerve pierces the dura close to the upper border of the apex of the petrous
part of the temporal bone and enters the cavernous sinus by passing below the
petrosphenoid ligament within a dural tunnel (Dorello's canal)

28. Relations of cavernous sinuses
Medially: Pituitary gland, body of sphenoid containing sphenoidal air sinuses
Laterally: Trigeminal Ganglia and Uncus of Temporal lobe
Superiorly: U-Shape loop of Internal Carotid artery forming Siphon
Inferiorly: Greater wing of Sphenoid

29. Communications of the cavernous Sinus:
• Facial Vein : Superior opthalmic and angular veins
• Superior Sagittal Sinus : Superficial Middle cerebral veins
• Pterygoid venous plexus: Emissary veins
• Transverse Sinus: Superior petrosal sinus
• Internal Jugular vein: Inferior Petrosal Sinus
• Opposite Cavernous sinus: Anterior and posterior
• intercavernous sinus

30. Carotico-cavernous fistula

32. THANKS