Head FINAL Flashcards
branches of the facial nerve
-temporal: Controls your forehead muscles.
-Zygomatic: Helps you close your eyes.
-Buccal: Allows you to move your nose, blink and raise your upper lip and corners of your mouth to make a smile (buccinator)
-Marginal mandibular: Draws your lower lip down (like a frown) and travels through your middle ear to help you respond to loud noises.
-Cervical: Controls movement in your chin and lower corners of your mouth.
Bells Palsy
-facial nerve
-viral infection- HSV1 - peripheral (in ex at least)
-parotid tumors- ipsilateral upper and lower
-central/cortical lesion- lower half of face weakness of contralateral side
-peripheral lesion- upper and lower weakness of ipsilateral side of face
tongue
-posterior 1/3- bitter -> glossopharyngeal (taste and general)
-lingual nerve is branch of V3 - 2/3 of tongue (sensation)
-facial nerve- anterior 2/3 tongue- taste
-hypoglossal- motor
facial arterial supply
-external carotid artery
-branches: facial, temporal, maxillary
-maxillary -> middle meningeal
-facial artery has submental, superior and inferior labial arteries
-superior labial artery- concern with upper vermillion border bleed -> if scabs and falls off it can exanguate
subaponeurotica (areolar) tissue
-permits venous blood flow from the dural sinuses to the venous vessels of scalp
-emissary veins- potential route for infection
-abscess, thrombosis of superior sagital sinus, infection, purulent
-laceration to scalp can cause acute blood loss anemia
-superior sagittal sinus bleed -> slow bleed -> subdural hematoma
subdural hematoma
-bleeding within meninges- below dura mater in the subarachnoid space
-superior sagittal sinus- slow bleed
-tears to bridging VEINS MC
-banana shape
-slow deterioration
-can cause cardiac arrhythmias -> medulla oblongata injury
-white shade on image - blood
-gray shade- a chronic bleed -> maybe an alcoholic who hit their head and dont remember -> hygroma -> CSF
-edema causes shift
-can drain in ER in an emergency bc its venous and lower pressure compared to epidural
fontanelles
-window to intracranial pressure
-depressed- hypovolemic, dehydrated, pancreatitis, blood loss, decrease IOP
-bulging- tumor, fluid overload
-sunset sign- iris/pupil is down at bottom of the eye -> hydrocephalus
-anterior, sphenoid, mastoid, posterior fontanelles
cribriform plate
-base
-can easily injury brain -> abrasion, contusion, laceration
-rhinorrhea -> CSF -> infection back up into brain
-no NG tube for basilar skull fracture or facial trauma -> you can put tube through cribriform plate and into the brain
-cribriform plate fracture -> ipsilateral olfactory loss
arachnoid mater
-suspends brain in cranial cavity
-collagen and elastin fibers
-subarachnoid space is beneath -> CSF that cushions brain
subarachnoid bleed
-wispy
-rupture of saccular aneurysm
-meningeal irritation, severe headache, stiff neck, often loss of consciousness
CSF
-water, protein, salts
-cushions CNS
-made in largest 2 ventricles of brain
-medium for nutrients and waste products to diffuse into and out of brain
-can drain to external passageway (can be pushed into spinal cord) if ICP is high -> eval target or halo sign
-8% of cranial space
cranium
-brain 80% -> cerebrum, cerebellum, brainstem
-brain receives 15% CO, 20% O2 -> unconscious within 10s and death in 4-6 mins without blood
-CSF 8%
-12% blood vessels and blood
cerebrum
-conscious though
-personality -> Frontal
-speech
-motor control
-visual
-auditory
-tactile perception
-parietal -> motor and sensory, memory and emotion
-occipital -> sight
-temporal -> long term memory, hearing, speech, taste, smell
splitting of the brain
-falx cerebri- divides cerebrum into right and left hemispheres
-central sulcus- fissure splitting it into right and left -> each hemisphere controls opposite side of body
-tentorium- fibrous sheet within occipital region
-brain stem perforates through incisura tentorium cerebelli
-oculomotor nerve travels along tentorium to front
-left hemi -> math and language interpretation (occipital) , writing (parietal), speech (frontal)
-right hemi -> non verbal imagery
basilar fracture
-fracture to bones forming base
-occipital around foramen magnum
-sphenoid
-temporal
-roof of orbit
-CSF rhinorrhea or otorrhea
-pterion fracture -> middle meningeal artery lies below in lateral calvaria -> epidural hematoma -> death
emissary veins
-loose connective tissue of scalp -> danger area
-infection can spread into cranial cavity via emissary veins -> meninges
-can cause black eyes -> spreads to eyes and nose
-cant spread to neck
occlusion of cerebral veins and dural venous sinuses
-from clots, venous inflammation, or tumor
-facial veins connect to cavernous sinus via superior ophthalmic veins
-thrombophlebitis of facial vein -> infected thrombus into cavernous sinus -> thrombophlebitis of cavernous sinus
fracture of cranial base
-cranial base fracture usually tears dura -> CSF leak
-internal carotid artery may be torn -> arteriovenous fistula within cavernous sinus
-arterial blood rushes into cavernous sinus -> overfloods into ophthalmic veins -> pulsating exophthalmos
-chemosis
-concern for oculomotor, trochlear, V1, V2, and abducens
epidural hemorrhage
-Bleeding between dura mater and skull
-Involves arteries- Middle meningeal artery most common
-Rapid bleeding and reduction of oxygen to tissues
-Herniates brain toward foramen magnum
-hematoma -> talking and fine -> all the sudden they arnt -> death
-football- self enhancing
-shift > 5mm -> problem
-loss of consciousness -> lucidness -> coma
brainstem
-central processing
-communication junction among - cerebrum, spinal cord, cranial nerves, cerebellum
-midbrain
-pons- communication between diff parts of brain, sleep
-medulla oblongata- breathing, cardiac, BP
midbrain
-Upper portion of brainstem
-Structures
-Hypothalamus- Endocrine function, vomiting reflex, hunger, thirst, Kidney function, body temperature, emotion
-Thalamus- Switching center between pons and cerebrum
-thalamus is Critical element in Ascending Reticular Activating System (A-RAS) -> ESTABLISHES CONSCIOUSNESS
-thalamus is Major pathways for optic and olfactory nerves
-Associated structures
CNS circulation
-arterial:
-4 major arteries- 2 internal carotid arteries from common carotid AND 2 vertebral arteries
-circle of willis- internal carotids and vertebral arteries -> encircle the base of brain
-venous:
-venous drainage occurs through bridging veins
-bridge dural sinuses
-drain into internal jugular veins
blood brain barrier
-less permeable than elsewhere in body
-DOES NOT allow flow of interstitial proteins
-Reduced lymphatic flow
-Very protected environment
-Blood acts as irritant resulting in cerebral edema
-NO highly charged, large, not lipid soluble can go through
-hepatic disease- fugal flow -> reverse flow ends up into systemic circulation before going through liver -> ammonia -> hepatic encephalopathy
-edema when blood brain barrier abnormal -> irritation of parenchyma -> high ICP
cerebral perfusion pressure
-ICP usually less than 10 mmHg
-MAP must be at least 50 mmHg to ensure adequate perfusion
-at least MAP 65 and higher than ICP
-ICP > 20 danger zone
-CPP- Pressure moving blood through the cranium
-CPP = MAP - ICP
-if ICP is higher than MAP -> we cant perfuse -> anoxia
-go up on MAP or go down on ICP -> better flow
-ex. raise the BP and catheter into ventricle to remove pressure
-rapid increase in ICP - herniation at 60
-pressure on the pons
