Dural Folds

🧠 1. Superior Sagittal Sinus

Q: Where is the superior sagittal sinus located?

A: Upper fixed border of the falx cerebri.

Q: Where does it begin?

A: At the foramen caecum.

Q: Where does it terminate?

A: Confluence of sinuses, usually → right transverse sinus.

Q: What does it receive?

A: Superior cerebral veins + CSF through arachnoid villi/granulations.

🧠 2. Inferior Sagittal Sinus

Q: Where is it located?

A: Free lower margin of the falx cerebri.

Q: How does it terminate?

A: Joins the great cerebral vein → forms the straight sinus.

Q: What does it receive?

A: Cerebral veins from the medial cerebral hemispheres + veins of falx cerebri.

🧠 3. Straight Sinus

Q: Where is it located?

A: Junction of falx cerebri + tentorium cerebelli.

Q: How is it formed?

A: Inferior sagittal sinus + great cerebral vein.

Q: Where does it terminate?

A: Confluence of sinuses, usually → left transverse sinus.

⭐ Remember:

Inferior sagittal + Great cerebral vein = Straight sinus

🧠 4. Transverse Sinuses

Q: Where are they located?

A: Along the posterior and lateral attachments of the tentorium cerebelli.

Q: Where do they begin?

A: At the internal occipital protuberance / confluence of sinuses.

Q: Right transverse sinus is usually continuous with?

A: Superior sagittal sinus.

Q: Left transverse sinus is usually continuous with?

A: Straight sinus.

Q: Where do they terminate?

A: Continue as the sigmoid sinuses.

Q: What do they receive?

A: Superior petrosal sinus + cerebral veins + cerebellar veins.

🧠 5. Sigmoid Sinuses

Q: What are sigmoid sinuses continuations of?

A: Transverse sinuses.

Q: Where are they located?

A: In grooves of the parietal, temporal, and occipital bones.

Q: Where do they terminate?

A: Pass through the jugular foramen → become the internal jugular veins.

⭐ Flow:

Transverse sinus → Sigmoid sinus → Internal jugular vein

🧠 6. Cavernous Sinuses

Q: Where are the cavernous sinuses located?

A: On either side of the sella turcica, lateral to the body of the sphenoid.

Q: What do they receive?

A:

Cerebral veins

Ophthalmic veins

Emissary veins from pterygoid plexus

Q: What structures pass THROUGH the cavernous sinus?

A: Internal carotid artery + CN VI (Abducent).

Q: What nerves are in its lateral wall from superior → inferior?

A: III → IV → V1 → V2

⭐ Very important:

Inside: ICA + VI

Lateral wall: III, IV, V1, V2

Q: Why is the cavernous sinus clinically important?

A: Infection can spread from extracranial → intracranial sites and damage the nerves passing through/within its walls.

🧠 7. Superior Petrosal Sinus

Q: Where is it located?

A: Superior margin of the petrous temporal bone.

Q: Where does it begin?

A: Posterior end of the cavernous sinus.

Q: Where does it terminate?

A: Transverse sinus.

Q: What does it receive?

A: Cerebral + cerebellar veins.

⭐ Flow:

Cavernous → Superior petrosal → Transverse

🧠 8. Inferior Petrosal Sinus

Q: Where is it located?

A: Groove between the petrous temporal bone + occipital bone.

Q: Where does it begin?

A: Posterior end of the cavernous sinus.

Q: Where does it terminate?

A: Internal jugular vein.

Q: What does it receive?

A: Veins from the cerebellum, internal ear, and brainstem.

⭐ Flow:

Cavernous → Inferior petrosal → Internal jugular vein

🧠 9. Basilar Sinus

Q: Where is the basilar sinus located?

A: On the clivus, posterior to the sella turcica.

Q: What does it connect?

A: Connects the right and left inferior petrosal sinuses and communicates with the vertebral venous plexus.

🧠 10. Occipital Sinus

Q: Is it paired or single?

A: Single.

Q: Where is it located?

A: In the falx cerebelli, against the occipital bone.

Q: Where does it begin?

A: Near the foramen magnum.

Q: What does it communicate with?

A: Vertebral veins.

Q: Where does it drain?

A: Confluence of sinuses.

🧠 11. Sphenoparietal Sinuses

Q: Are they paired or single?

A: Paired.

Q: Where are they located?

A: Inferior surface of the lesser wings of the sphenoid.

Q: Where do they drain?

A: Into the anterior ends of the cavernous sinuses.

اهم مسارات للحفظ

Superior sagittal → Confluence → Right transverse → Sigmoid → Internal jugular

Inferior sagittal + Great cerebral vein → Straight → Confluence → Left transverse → Sigmoid → Internal jugular

Cavernous → Superior petrosal → Transverse

Cavernous → Inferior petrosal → Internal jugular