Chapter 6: Head and Neck (continued) Flashcards
What are the major tributaries that drain into the dural venous sinuses?
cerebral and cerebelli veins
Emissary
diploic veins
Arachnoid granulations
Meningeal veins
Where do the cerebral and cerebelli veins drain? Where are they located?
pass across the subdural space and drain into the sinuses
Describe the emissary veins. Where they course and what their function is?
veins are valveless channels that course through bones of skull and allow dural sinuses to communicate with extracranial veins
Diploic veins drain into what area of the body?
drain the spongy (diploe) core of flat bones
What is the purpose of arachnoid granulations?
where CSF returns to the venous circulation
Dural venous sinus picture
Superior sagittal sinus location?
midsagittal plane superior aspect of falx cerebri
Inferior sagittal sinus location?
midsagittal plane near inferior margin of falx cerebri
Straight sinus is formed by union of what what structures?
formed by union of inferior sagittal sinus and great cerebral vein
Where is the occipital sinus located?
small sinus found in the posterior border of tentorium cerebelli
Confluence of sinuses is formed by what union?
union of superior sagittal, straight, and occipital sinuses posteriorly at the occipital bone
Where are the transverse sinuses located?
paired sinuses in the tentorium cerebelli and attached to the occipital bone
Where are the sigmoid sinuses located ?
paired and form a S-shaped channel in the floor of the posterior cranial fossa
Where are the cavernous sinuses located?
On either side of the body of the sphenoid bone
Each cavernous sinus receives blood primarily from which veins?
orbit (ophthalmic veins)
and via emissary veins from the deep face (pterygoid venous plexus)
Why are the cavernous sinuses the most clinically significant dural sinuses?
because of their relationship to a number of cranial nerves CN III and CN IV and the ophthalmic and maxillary divisions of the trigeminal nerve are located in lateral wall of the sinus.
CN VI and internal carotid artery are located centrally in the sinus
Coronal Section Through Pituitary Gland and Cavernous Sinus
Cavernous Sinus Thrombosis.
Infection can spread from the superficial and deep face into the cavernous sinus, producing a thromobosis that may result in swelling of sinus and damage the cranial nerves that are related to the cavernous sinus
What does an epidural hematoma result from?
trauma to the lateral aspect of the skull which lacerates the middle meningeal artery
Epidural hemorrhage forms what shape?
forms a lens-shaped (biconvex) hematoma at the lateral hemisphere
Symptoms of epidural hematoma?
associated with a momentary loss of consiousness followed by a lucid (asymptomatic) period of up to 48 hours; then a rapid loss of consciousness once again
elevated ICP
What does a subdural hematoma result from?
a head trauma that tears superficial (bridging) cerebral veins at the point where they enter the superior sagittal sinus
What shape does a subdural hematoma form?
crescent-shaped hematoma at the lateral hemisphere
Symptoms of subdural hematoma?
signs of elevated ICP or headache and nausea
A subarachnoid hemorrhage results from what?
rupture of a berry aneurysm at the circle of Willis
What is the most common site of a rupture of the berry aneurysm?
anterior part of the circle of Willis at the branch point of the anterior cerebral and anterior communicating arteries.
What is the only muscle innervated by CN IV?
The trochlear nerve innervates the superior oblique muscle
What is the only muscle innervated by CNVI?
The abducens nerve innervates the lateral rectus
What are the extraocular muscles innervated by CN III?
4 of the 6
superior, inferior, and medial rectus, and the inferior oblique plus the levator palpebrae superioris
The smooth muscle of the levator palpebrae is innervated by what nerves? What is the name of this smooth muscle?
superior tarsal muscle
sympathetic fibers
Muscles of the eye.
