Cranial Cavity and Meninges Flashcards
why can fractures of the pterion be life threatening?
b/c it overlies the frontal branches of the middle meningeal vessels
what does an untreated middle meningeal vessel hemorrhage cause?
death in a few hours
how can an infection of the face spread to the cavernous sinus and pterygoid venous plexus?
b/c facial v. -> superior ophthalmic v. -> cavernous sinus
also facial v. -> inferior ophthalmic v. + deep facial v. -> pterygoid venous plexus
what is thrombophlebitis of the facial vein?
inflammation of the facial vein with secondary thrombus (clot) formation
thrombophlebitis of the cavernous sinus
if pieces of an infected clot extend into the intracranial venous system
what is the danger triangle of the face? why is it called this?
the triangular area from the upper lip to the bridge of the nose - b/c infection of facial veins can spread to dural venous sinuses
what can fractures of the cranial base cause?
tears in the dura with resulting leakage of CSF
clinical significance of the dural border cell layer
flattened fibroblasts that are separated by large extracellular spaces - constitutes a plane of structural weakness at the dura-arachnoid jxn
what do space-occupying lesions in the supratentorial compartment cause?
increased intracranial pressure
what happens with tentorial herniation?
- temporal lobe may be lacerated by the tough tentorium
- oculomotor nerve may be stretched/compressed
what do pituitary tumors cause?
stretching/bulging of diaphragma sellae, producing disturbances in endocrine fxn
what can cause occlusion of cerebral veins and dural venous sinuses?
- thrombi
- thrombophlebitis
- tumors
which dural venous sinuses are most frequently thrombosed?
- transverse
- cavernous
- superior sagittal
what usually causes cavernous sinus thrombosis?
-infections in orbit, nasal sinuses, superior part of face (danger triangle)
what can acute meningitis cause in the cavernous sinus?
septic thrombosis
what is an arteriovenous fistula in the cavernous sinus?
arterial blood rushing into cavernous sinus, enlarging it and forcing retrograde blood flow into venous tributaries, especially ophthalmic veins -> causes pulsating exophthalmos and chemosis
what is chemosis?
engorged conjunctiva
what is pulsating exophthalmus?
protruding eyeball that pulsates in synchrony w/ radial pulse
what can distention of the scalp or meningeal vessels cause and why?
headache - b/c dura is sensitive to pain
what is leptomeningitis?
inflammation of the leptomeninges (arachnoid and pia) from pathogenic microbes
with leptomeningitis, where is the infection usually confined to?
subarachnoid space, arachnoid and pia
what is septicemia?
blood poisoning
what can cause acute purulent meningitis?
infection w/ almost any pathogenic bacteria
what is extradural/epidural hemorrhage?
- ARTERIAL blood from torn branches of middle meningeal artery
- collects b/w external periosteal layer of dura and calvaria
- strips dura from cranium
- forms epidural hematoma
