14-A Cranial Cavity Flashcards
Subarachnoid space contains _____ (liquid).
CSF
Is there a epidural space in the cranium?
no, just a potential space
Describe the path of CSF through the ventricular system.
it begins in the lateral ventricles then travels through the intervetnricular foramen to the third ventricle, from there, the cerebral aqueduct carries the CSF to the forth ventricle to the central canal of the spinal cord, at the base of the spinal cord, CSF primarily leaves throughout eh median or two lateral apertures to fill the cavity surrounding the brain
What specialized structure produces cerebrospinal fluid?
choroid plexus which features a special relationship between the capillaries embedded in the pia mater and the specialized ependymal cells NOTE exchange across the blood-CSF barrier is tightly regulated
What are the function(s) of CSF?
metabolic functions (delivers nutrients, removes waste and maintains fluid balance)
How does CSF get returned to venous circulation from the subarachonid space?
through arachnoid grandulations/ arachnoid villi
Which space is the cistern magna included in?
the subarachnoid space
What is hydrocephalus?
enlarging of ventricular system management via shunt to peritoneum
What layer is reflected to create venous sinuses?
meningeal dura reflections
Name the three dural reflections.
falx cerebri, tentorium cerebelli, and falx cerebelli
What is the portion of the dural reflection that curves around the area filled by the brainstem?
tentorial notch
Which two sinuses run with the falx cerebri
the superior sagittal sinus, the inferior sagittal sinus
What sinus joins the inferior sagittla sinus and the transfers sinus?
straight sinus
What sinus joins the tranverse sinus to the internal jugular?
sigmoid sinus
Which sinuses form the confluence of sinuses?
superior sagittal sinus, straight sinus and transverse sinus
All dural venous sinuses drain in ?
internal jugular veins
T/F the dural sinuses communicate with vein
true, via emissary veins
Where is the cavernous sinus located, between which two layers
between the 2 layers of dura at the base of the brain
What are the three routes that the cavernous sinus can drain?
superior ophthalmic v, the pterygoid plexus and the superior and inferior petrosal sinuses
Which cranial nerves run through the cavernous sinus?
CN III, IV, V1, V2 against the wall and CNVI inside the sinus… also the internal carotid
When might you get bulging eyes due to a circulation issue?
if the carotid artery is damaged within the cavernous sinus, cause the area to fill with blood
Which space contains the arterial blood supply vs the venous supply?
epidural space (potential) contains the arterial blood supply to the dura mater and the subdural space (potential) contains the veins
What artery supplies blood to the dura?
the middle meningeal artery, branch of the maxillary artery, enters the infra temporal fossa, runs in epidural space from the foramen spinosum
What is the pterion?
very thin area of bone where the frontal, parietal, temporal and the sphenoid bone meet
What is the potential cause of a epidural hematoma?
often the result of a middle menial artery rupture, blood accumulates in the skull and the dura with a rapid increase in intracranial pressure
What is the potential cause of a subdural hematoma?
result of a blow to the head, shearing damages cerebral veins where they penetrate the dura, blood accumulates between dura and arachnoid space
Where is a subarachnoid hematoma?
rupture of cerebral artery or vein where the blood accumulates in the subarachnoid space, leads to meningeal irritation
What do you call the bones that protect the brain from above and below?
Neurocranium: calvarium and the cranial base (facial skeleton in front)
What are the three fossa of the cranium
anterior, middle, posterior cranial fossae
Which bones make up the anterior cranial fossa?
frontal sphenoid, ethmoid and parietal
What bones make up the middle cranial fossa?
sphenoid, temporal, parietal
What bones make up the cranial fossa?
temporal occipital, sphenoid, parietal aaand the tentorium cerebelli underneath
CN II-XII exit the brainstem ___ to the tentorium crebelli
inferior
Which CN travel intra or epidurally from PCF to MCF to exit skull?
CN III to VI
Which CN exit dura mater and skull in the PCF
CN VII to XII
What are the features of the anterior cranial fossa
only the cribriform place superiorly
What are the features of the middle cranial fossa?
optic canal, superior orbital fissure, the foramen rotundum, the foramen oval, the foramen spinosum, the foramen lacernum and the carotid canal (only from below)
What is the function of the orbital fissure?
passage from middle cranial fossa to orbit containing oculomotor, trochlear, opthalmic division of V, abducens
The carotid canal passes (over/ through) the foramen lacerum.
over (foramen lacerum is covered by fibrocartilage)
What are the features of the posterior cranial fossa?
the internal acoustic meatus, jugular foramen, hypoglossal canals, foramen magnum, petrotympanic fissure, stylomastoid foramen, and the condylar canal
What to major arteries supply the circle of willis
vertebral and interal carotid arteries (ascend through the neck without branching
Why is it important to recognize the relationship between arteries and cranial nerves?
they are interdigitate, vascular incidents can lead to CN syndromes
