Cerebrospinal Fluid and Vascular System Flashcards
Differentiate between Contralateral and Ipsilateral in relation to lesions of nerves.
Contralateral: Lesion is on RIGHT and deficit on LEFT
Ipslateral: Lesion AND deficit on RIGHT
How much does the brain weigh?
How much does the head weigh?
3 pounds
14 pounds
Define:
- Funiculus
- Fasciculus
- Tract
- Lemniscus
- Funiculus
- Fasciculus: Bundle of White Fibers
- Tract: Bundle of Fibers that have a common origin, destination and function
- Lemniscus: Bundle of crossed, secondary nerve fibers in a conscious sensory pathway (it will result in CONTRALATERAL deficits).
Explain the different Meninges and Spaces within the brain.
- Epidural Space
- Dura Mater
- Subdural Space
- Arachnoid Membrane
- Subarachnoid Space
- Pia Mater
What is the significance of the Tentorial Notch?
Where the brainstem pass through SUPRAtentorial to INFRAtentorial
Describe the different different types of Herniations.
- Falx herniation: “Midline Shift”, may not present with any symptoms
- Tentorial (uncal) Herniation: When the brain starts going down towards the midbrain (NOT good)
- Tonsillar Herniation: Can push the Tonsil of the Cerebellum through the Foramen Magnum
Explain Subdural Hematomas.
Between the Dura Mater and Arachnoid Membrane
*** Head trauma may cause these cerebral (bridging) veins to rupture as they cross the subdural space.
- Appear as a Cresent Shape Radio Opacity on CT
**** Present as the WORST HEADACHE you have ever had in your life!
Explain Epidural Hematomas.
How does it present?
Which artery is involved?
Which boney structure does this artery pass through?
Between ENDOcranium and Dura Mater
*** Confined by the Sutures (Where the Dura Mater is MOST closely attached to the Skull)
Classic presentation of a “lucid interval” of immediate unconsciousness post-trauma followed with rapid mental decline as there is increased pressure and herniation on the brain.
- Middle Meningeal Artery
- Passes through the Foramen Spinosum
What is Papilledema?
Increased intracranial Pressure may result in swelling of the OPTIC DISC
- Decreased venous drainage because there are small veins to the Optic Disc that are going to be compressed
Explain Subarachnoid Hemorrhage.
All of the major blood vessels supplying the CNS pass through or course in the subarachnoid space.
Rupture of one of these vessels in this space is called a subarachnoid hemorrhage, and is indicated by the presence of ERYTHROCYTES in the CSF
*** CSF is usually sampled by inserting a needle into either the cerebellomedullary or lumbar cisterns
What can happen if you have trauma to the midbrain?
Severe blows to the head may cause the sharp edge of the INCISURA (tentorial notch of Tentorium Cerebelli) to lacerate or contuse the brainstem.
Describe the drainage of the Dural Venous Sinuses that you would usually see in 2/3 of patients.
Differentiate between Thrombosis of the posterior portion of the superior sagittal venous/right transverse venous sinus AND posterior portion of the straight venous sinus/left transverse venous sinus.
Superior Sagittal Sinus –> Right Transverse Sinus
Straight Sinus –> Left Transverse Sinus
Describe the Ventricular System in the Brain. What is it called when you have an accumulation of CSF? What happens if you have a blockage in the Cerebral Aqueduct?
Lateral Ventricle –> Interventricular foramen of Monroe–> 3rd Ventricle –> Cerebral Aqueduct –> 4th Ventricle –> Exits via the Lateral and Median Apertures
*** Hydrocephalus
*** You will have a buildup of CSF in the Lateral and 3rd Ventricles
Describe the different types of External Hydrocephalus.
Accumulation of CSF in the SUBARACHNOID space
*** Supratentorial Hydrocephalous is associated with Alzheimer’s Disease!
Describe Internal Hydrocephalus.
Blockage from Lateral Ventricles to Medial/Lateral Foramina!