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!
Describe Communicating Hydrocephalus.
Obstruction at the TENTORIAL NOTCH in the Subarachnoid Space (External Hydrocephalus) will cause hypertrophy of the Ventricles (Internal Hydrocephalus)
- Choroid Plexus
- Arachnoid Villi
- External Hydrocephalus
- Hypertrophy of the Lateral and 3rd Ventricles
- Hydrocephalus of the Lateral Ventricles
- Communicating Hydrocephalus
- Medial and Lateral Foramina
- Arachnoid Villus; Secondary (Chemical) Meningitis
Relate Regional Cerebral Blood Flow with different problems in the brain. Which two regions are prone to injury?
Certain areas of the brain (distal branches of the cerebral arteries) and particular neuronal populations (pyramidal cells of the hippocampus especially the CA1 or Sommer’s sector) are consistently damaged in severe ischemic injury.
Where are the terminations of the Internal Carotid Artery and Vertebral Arteries located within?
Subarachnoid Space
*** As these branches penetrate into the substance of the brain, they are progressively surrounded by the tapered perivascular space (Virchow-Robin space) and the pia mater or blood-brain barrier.
Cortical branches of the Anterior Cerebral Artery will supply which region?
Anterior 2/3 of the medial side and supero-lateral portion of the hemisphere.
*** Branches of the ACA frequently supply the paracentral lobule region, and, therefore, occlusions may result in contralateral paresis and/or paraesthesia of the leg and foot.
Where is the most common spot for hemmorhage?
Around the Basal Ganglia and INTERNAL CAPSULE (80%)
*** Thalamostriate of the Middle Cerebral Artery
Which artery has the HIGHEST incidence of Cerebral Aneurysms?
Anterior Cerebral Artery (35%)
Describe the distribution of the Middle Cerebral Arteries.
Supplies the LATERAL sides of the brain
Thrombosis can result in Broca’s aphasia: Inability to formulate SPEECH
Thrombosis can result in Wernicke’s Aphasia: Inability to INTERPRET something that another person says
Can result in Motor and Sensory defects in the Contralateral UPPER LIMB and Head!
What are the 3 main arteries for Posterior Circulation of the Brain? List the arteries that will arise from these two.
- Vertebral: Anterior Spinal, Posterior Spinal, Posterior Inferior Cerebellar
- Basilar: Anterior Inferior Cerebellar, Superior Cerebellar
- Posterior Cerebral
