CSF Circulation Flashcards
What is CSF?
- Ultrafiltrate of blood
- Produced by the choroid plexus
found in the walls of the
ventricles - 150 ml
- 125 ml is intracranial
- The ventricles contain about 25
ml - 100 ml is located in the cranial
subarachnoid space - Secreted at a rate of 0.35–0.40
ml per minute
What are the key functions of CSF?
Functions of CSF:
Lubrication for the brain and spinal cord
Acts as a shock absorber
Transports nutrients, waste products, and hormones
Name the key ventricles of the brain
Lateral, Third, Forth ventricles
Describe the lateral ventricles and their relations
Location: Cerebral hemispheres
Parts: Body, Anterior horn, Posterior horn, Inferior horn
Relations:
Caudate nucleus: Lateral wall of Anterior horn and Body
Thalamus: Lateral wall of Body
Hippocampus: Floor of Inferior horn
Describe the third ventricle and their relations
Location: Cerebral hemispheres
Parts: Body, Anterior horn, Posterior horn, Inferior horn
Relations:
Caudate nucleus: Lateral wall of Anterior horn and Body
Thalamus: Lateral wall of Body
Hippocampus: Floor of Inferior horn
Describe the forth ventricles and their relations
Location: Posterior to Pons and Medulla; Anterior to Cerebellum
Recesses: 2 Lateral, 1 Median
Describe the flow of CSF through the ventricular system.
CSF Flow Pathway:
1️⃣ Lateral Ventricles → Interventricular Foramen of Monro
2️⃣ Third Ventricle → Cerebral Aqueduct
3️⃣ Fourth Ventricle → Subarachnoid space via:
Median Aperture (Foramen of Magendie)
Lateral Apertures (Foramina of Luschka)
How is CSF absorbed?
Absorption of CSF:
Occurs via arachnoid granulations
From the subarachnoid space → Into the dural venous sinuses
What is hydrocephalus, and what are its types?
Hydrocephalus:
Enlargement of the cranial cavity due to CSF accumulation
Types:
1️⃣ Obstructive Hydrocephalus: Blockage in ventricular system (e.g., tumor, aqueduct stenosis)
2️⃣ Non-obstructive Hydrocephalus: Impaired absorption of CSF (e.g., meningitis, trauma)
What are the major cisterns in the subarachnoid space?
🌊 Subarachnoid Cisterns:
1️⃣ Interpeduncular cistern
2️⃣ Pontine cistern
3️⃣ Cisterna Magna
Describe the location and function of the interpedunular cistern
Location:
Lies between the cerebral peduncles at the base of the brain (interpeduncular fossa).
Functions:
- Conduit for CSF flow: Facilitates CSF movement from the third ventricle to the surrounding spaces.
- Protects key neurovascular structures:
- Encases the oculomotor nerve (CN III) as it exits the midbrain.
- Accommodates parts of the circle of Willis and the basilar artery bifurcation, essential for blood supply to the brain.
Describe the location and functions of the Pontine Cistern
Location: Located anterior to the pons and the medulla oblongata, continuous with the interpeduncular cistern.
Functions:
CSF reservoir: Acts as a pool for CSF and helps in the distribution of CSF to other cisterns.
Protects cranial nerves:
Surrounds cranial nerves VI (Abducens), VII (Facial), and VIII (Vestibulocochlear).
Pathway for arteries: Accommodates the basilar artery and its branches, vital for brainstem perfusion.
Describe the location and function of the Cisterna Magna (Cerebellomedullary Cistern)
Location: Largest cistern, located posterior to the medulla oblongata and inferior to the cerebellum.
Functions:
Major CSF collection point: Collects CSF from the fourth ventricle via the median aperture (Foramen of Magendie).
Distribution hub: Distributes CSF to the subarachnoid spaces around the spinal cord and brain.
Cushioning effect: Provides additional protection to the brainstem and lower cerebellum by reducing mechanical shocks.
