Dural Venous Sinuses

Structure

Fig. 8.45 - Dural Venous Sinuses (Gray's Anatomy for Students)

Tributaries (What drains into them)

Individual Sinuses

Fig. 8.46 - All Dural Venous Sinuses (Gray's Anatomy for Students)

1. Superior Sagittal Sinus

• Runs in the superior border of the falx cerebri
• Begins anteriorly at the foramen cecum (may receive a small emissary vein from the nasal cavity)
• Ends posteriorly at the confluence of sinuses, usually bending right into the right transverse sinus
• Has lateral extensions called lateral lacunae containing arachnoid granulations
• Receives: superior cerebral veins, diploic veins, emissary veins, CSF

2. Inferior Sagittal Sinus

• Runs in the inferior (free) margin of the falx cerebri
• Receives a few cerebral veins and veins from the falx cerebri
• Ends at the anterior edge of the tentorium cerebelli, where it joins the great cerebral vein to form the straight sinus

3. Straight Sinus

• Runs along the junction of the falx cerebri and tentorium cerebelli
• Formed by the union of the inferior sagittal sinus + great cerebral vein (of Galen)
• Ends at the confluence of sinuses, usually bending left into the left transverse sinus
• Receives: posterior cerebral veins, superior cerebellar veins, falx veins

4. Confluence of Sinuses (Torcular Herophili)

• A dilated space at the internal occipital protuberance
• Receives the superior sagittal, straight, and occipital sinuses
• Drains into the right and left transverse sinuses

5. Transverse Sinuses (paired)

• Extend horizontally from the confluence of sinuses along the posterior and lateral attachments of the tentorium cerebelli
• Right transverse sinus usually drains the superior sagittal sinus; left drains the straight sinus
• Also receive the superior petrosal sinus, inferior cerebral and cerebellar veins, diploic and emissary veins

6. Sigmoid Sinuses (paired)

• Continuation of the transverse sinuses, turning inferiorly in an S-shaped course
• Groove the parietal, temporal, and occipital bones
• End at the jugular foramen where they become the internal jugular veins
• Receive cerebral, cerebellar, diploic, and emissary veins

7. Occipital Sinus

• Lies in the falx cerebelli against the occipital bone
• Begins at the foramen magnum (communicates with the marginal sinus and vertebral venous plexus)
• Drains into the confluence of sinuses

8. Cavernous Sinuses (paired) - Clinically Important

• Located on either side of the body of the sphenoid / sella turcica
• Receive blood from: cerebral veins, ophthalmic veins (from orbit), emissary veins (from pterygoid plexus)
• Connected to each other via intercavernous sinuses (anterior and posterior to the pituitary stalk)
• Drain via the superior petrosal sinus (to transverse sinus) and inferior petrosal sinus (to internal jugular vein)

• Running through the sinus: internal carotid artery (with sympathetic plexus), abducent nerve [CN VI]
• In the lateral wall (superior to inferior): CN III (oculomotor), CN IV (trochlear), CN V1 (ophthalmic), CN V2 (maxillary)

9. Sphenoparietal Sinuses

• Run along the inferior surface of the lesser wings of the sphenoid
• Drain into the anterior ends of the cavernous sinuses
• Receive diploic and meningeal veins

10. Superior Petrosal Sinuses (paired)

• Drain the cavernous sinuses posterolaterally along the superior margin of the petrous temporal bone
• Connect the cavernous sinus to the transverse/sigmoid sinus junction
• Also receive cerebral and cerebellar veins

11. Inferior Petrosal Sinuses (paired)

• Run posteroinferiorly in a groove between the petrous temporal bone and basal occipital bone
• Drain the cavernous sinuses directly into the internal jugular veins at the jugular foramen
• Receive cerebellar veins, veins of the internal ear and brainstem

12. Basilar Sinuses / Basilar Plexus

• A venous plexus lying on the clivus between the marginal and cavernous sinuses
• Connects the two inferior petrosal sinuses and communicates with the vertebral venous plexus

13. Marginal Sinus

• Encircles the foramen magnum
• Connects the dural sinuses with the vertebral venous plexuses

Final Drainage Pathway

• also → (via inferior petrosal sinus) → directly into internal jugular vein

Clinical Highlights

1. Emissary veins - valveless, bidirectional; provide a route for extracranial infections (e.g., scalp cellulitis, mastoiditis) to reach the dural sinuses, leading to septic thrombosis
2. Cavernous sinus thrombosis - can result from spread of facial infections (via ophthalmic veins); manifests with painful ophthalmoplegia (CN III, IV, VI) and chemosis
3. Lateral/sigmoid sinus thrombosis - a known intracranial complication of otitis media/mastoiditis (the sigmoid sinus lies close to the mastoid air cells)
4. Subdural hematoma - tearing of bridging cerebral veins as they cross the dura to enter the sinuses
5. Superior sagittal sinus thrombosis - presents with headache, seizures, venous infarcts; associated with prothrombotic states, pregnancy, dehydration

• Gray's Anatomy for Students, pp. 1024-1027
• Color Atlas of Human Anatomy Vol. 2 (Internal Organs), pp. 134-135