Neuroanatomy: Ventricles Flashcards
Identify the following:
Lateral Ventricle:
- Anterior (frontal) horn
- Body
- Posterior (occiptal) horn
- Inferior (temporal) horn
- Atrium
Third Ventricle
Fourth Ventricle
Interventricular Foramen (Monroe)
Cerebral Aqueduct
Where is the Choroid Plexus and CSF contained?
Choroid Plexus: The floor of the Lateral ventricles, going throug the intraventricular foramen into the roof of the third ventricle, and the fourth ventricle
CSF: All ventricles, subarachnoid space, within the spinal canal
How many openings are there in the Fourth ventricle?
There are four openings
- Cerebral Aqueduct: Transfers CSF from 3rd ventricle to the 4th ventricle
- Two lateral foramens (foramen of Luschka): CSF drains leaves the fourth ventricle to the subarachnoid space through this.
- Median foramen (Foramen of Magendie): CSF drains from the 4th ventricle into the spinal cord.
What cistern sits under the 3rd ventricle?
Is the CSF in this area considered inside the brain or outside?
The Suprasellar Cistern sits under the third ventricle
This is considered outside the brain because by this point it is in the subarachnoid space (just about to go into the surrounding subarachnoid space.
The brain is just bathing in this.
Where isn’t the Choroid plexus found in the lateral ventricles?
The Anterior and Posterior horns (frontal and occipital)
What are the constituents of the CSF?
- Fluid is clear and colorless
- Very few cells in the CSF (1-8 cells/ml of lymphocytes/monocytes)
- Protein: 15-45 mg/dl
- Glucose: 60-80 mg/dl
- Opening Pressure (lumbar): Lateral recumbent position (50-200 mm H2O); Sitting position (200-300 mm H2O)
- We make ~ 500-700 ml/24 hours
- We renew our supply 3-5 times/day
What is the general route of CSF for leaving the ventricles and in the subarachnoid space?
It begins going through the ventricals and leaves the fourth ventricle through
- Median Foramen (Magendie)
- Lateral Foramen (Luschka)
After it enters the subarachnoid space it circulates around the spinal cord and brain stem where it then goes through the Tentorial Incisure –> arachnoid villi and the sinuses
What three forces push the CSF out of the subarachnoid space into the venous blood of the dural venous sinus?
- The CSF in the subarachnoid space has a higher hydrostatic pressure than venous blood in the dural sinuses
- Higher osmotic pressure pushing CSF into the blood (blood has more proteins, ions, etc.)
- Active transport of CSF by cells in the arachnoid villi
