Flashcards in Neuro - Anat & Phys (Dural venous sinuses, Ventricular system, & Hydrocephalus) Deck (18):
What are the dural venous sinuses?
Large venous channels that run through the dura
From where do dural venous sinuses drain? What do they drain into?
Drain blood from cerebral veins and receive CSF from arachnoid granulations. Empty into internal jugular vein.
Draw and label the Dural venous sinuses: (1) Confluence of the sinuses (2) Cavernous sinus (3) Great cerebral vein of Galen (4) Inferior sagittal sinus (5) Internal jugular vein (6) Jugular foramen (7) Sigmoid sinus (8) Sphenoparietal sinus (9) Superior saggital sinus (10) Superior ophthalmic vein (11) Straight sinus (12) Transverse sinus (13) Occipital sinus.
Pg. 463 in First Aid 2014 for image at bottom of page
What is the main location of CSF return via arachnoid granulations?
Superior sagittal sinus
Draw and label the ventricular system: (1) Anterior horn (2) Cerebral aqueduct (3) Foramen of Luschka (4) Foramen of Magendie (5) Foramen of Munro (6) Fourth ventricle (7) Lateral ventricles (8) Posterior horn (9) Third ventricle.
See p. 464 in First Aid 2014 for visual at top of page
What is the flow of CSF through the ventricular system?
Lateral ventricle --> 3rd ventricle via right and left interventricular foramina of Monro. 3rd ventricle --> 4th ventricle via cerebral aqueduct (of Sylvius). 4th ventricle --> subarachnoid space via: Foramina of Luschka = Lateral & Foramen of Magendie = Medial.
What makes versus reabsorbs CSF?
CSF is made by ependymal cells of choroid plexus; it is reabsorbed by arachnoid granulations and then drains into dural venous sinuses
How does CSF flow from lateral to third ventricles?
Lateral ventricle --> 3rd ventricle via right and left interventricular foramina of Munro
How does CSF flow from 3rd to 4th ventricles?
3rd ventricle --> 4th ventricle via cerebral aqueduct (of Sylvius)
How does CSF flow from 4th ventricle to subarachnoid space?
4th ventricle --> subarachnoid space via:
-Foramina of Luschka = Lateral
-Foramina of Magendie = Medial
What are the 2 major categories of Hydrocephalus?
(1) Communicating (nonobstructive) (2) Noncommunicating (obstructive)
What are 3 types of Communicating (nonobstructive) hydrocephalus?
(1) Communicating hydrocephalus (2) Normal pressure hydrocephalus (3) Hydrocephalus ex vacuo
What causes Communicating hydrocephalus? What are 3 consequences of it?
Decreased CSF absorption by arachnoid granulations, which can lead to increased intracranial pressure, papilledema, and herniation (e.g., arachnoid scarring post-meningitis).
What does not occur with Normal pressure hydrocephalus?
Does not result in increased subarachnoid space volume.
What are the 3 symptoms associated with Normal pressure hydrocephalus, and what causes them?
Expansion of ventricles distorts the fibers of the corona radiata and leads to the clinical triad of urinary incontinence, ataxia, and cognitive dysfunction (sometimes reversible); Think: "wet, wobbly, and wacky"
What characterizes Hydrocephalus ex vacuo? How is it distinguished from other communicating hydrocephalus & normal pressure hydrocephalus?
Appearance of increased CSF in atrophy (e.g., Alzheimer disease, advanced HIV, Pick disease); Intracranial pressure is normal; triad is not seen
What is observed on imaging in Hydrocephalus ex vacuo, and what causes this observation?
Apparent increase in CSF observed on imaging is actually result of decreased neural tissue due to neuronal atrophy