CEREBROVASCULAR - URR HHS

(rt) innominate artery/brachiocephalic artery(trunk)

1st major branch of AO arch, branches into rt CCA and rt subclavian artery

rt CCA originates from

innominate artery

lt CCA originates from

AO arch (2nd branch)

baroreceptors

nerve endings in the CCA bulb

where does the CCA bifurcate

the level of the upper border of the thyroid cartilage

what is the most common location of atherosclerosis

CCA bifurcation due to the flow disturbances

CCA bifurcates on which side lower

right

CCA demonstrates what kind of waveform

low resistance with mild diastolic clow

majority of the CCA blood enters where

ICA due to low resistance vascular bed distally

in most patients the ECA is located where

anterior medial to the CCA

what is the most common ECA/ICA variant

ECA posterior lateral to ICA

ECA branches supply

neck, thyroid, face, scalp

the ECA terminates at

superficial temporal artery

superior thyroidal artery

first branch courses inferior to thyroid, visible in most patients

lingual artery

anterior branch, supplies mouth/tounge

ascending pharyngeal artery

posterior branch, supplies pharynx

facial artery

anterior branch, supplies facial muscles, gives off numerous small branches before it terminates into angular artery

occipital artery

posterior branch, branches connect to the branches of the distal vertebral artery

posterior auricular artery

posterior branch, supplies the auricle and the scalp

superficial temporal artery

terminal branch of the ECA, gives rise to the maxillary artery, anterior and posterior branches

ECA collateral branches - superficial temporal artery

connects to small branches of the ophthalmic artery

ECA collateral branches - facial and maxillary artery

connects to small branches of the orbital artery

ECA collateral branches - ascending pharyngeal

connects to small branches of the vertebral artery

which artery demonstrated oscillations during diastolic flow using the temporal tap

superficial temporal artery (part of the ECA)

what kind of flow does the ECA have

high resistance, pulsatile, with mild antegrade diastolic flow

the ICA courses

cephalad to enter the cranium

which of the following is larger? the ECA or ICA

ECA

siphon area

distal ICA courses anterior then medial then posterior forming an "S" shape

tortuosity

S - shaped curve

kinking

takes a sharp turn, associated with symptomatic cerebral ischemia

what kind of course is most commonly associated with symptomatic cerebral ischemia

kinking

coiling

vessels form a circle during its course

ICA branches supply

eyes, nose, forehead, corpus callosum, frontal/parietal lobes

ophthalmic artery

first branch from siphon area inside cranium, not visible on carotid evaluation, branches into nasal, frontal, and supraorbital arteries

what are the other two main intracranial branches of the distal ICA

anterior choroidal artery and posterior communicating artery

ICA terminates

bifurcation of ACA and MCA at circle of willis

ICA supplies about how much arterial blood to the brain

75%

ICA has what kind of bloodflow

low resistance with slow acceleration and deceleration

periorbital arteries include

supraorbital arteries, frontal arteries, lacrimal arteries

supraorbital arteries

originate from the ophthalmic artery and joins the superficial temporal artery (branch of ECA)

frontal artery/supratrochlear artery

originates from ophthalmic artery, supplies nose with nasal artery

lacrimal artery

originates from the ophthalmic artery

vertebral arteries only supply how much blood to cerebrum

10-25%, 25% to the brain

the vertebral arteries course through which vertebrae's

C6 through C1

which vertebral artery is usually larger

left

the left and right vertebral arteries originate from which arteries

ipsilateral proximal subclavian artery

what is the normal velocity for the vertebral arteries

<50cm/s, similar to pattern of ICA

aberrant right subclavian artery/retroesophageal subclavian artery

where the subclavian artery can be a direct branch of the distal AO to lt subclavian, originates from dilated proximal desc AO

kommerell diverticulum

aberrant rt subclavian artery originating from a dilated segment of the proximal desc AO

aberrant right subclavian artery/retroesophageal subclavian artery can cause

dysphagia due to compression of the esophagus, can be associated with ortner syndrome

ortner syndrome

palsy of the recurrent laryngeal nerve

the subclavian arteries become the axillary artery at what level

first rib

branches of the subclavian artery

vertebral artery, internal mammary (internal thoracic artery), thyrocervical/costcocervical trunks

what kind of waveform does the subclavian artery have

triphasic, high resistance

obstruction waveform in the subclavian artery will present with

biphasic or monophasic

basilar artery supplies

superior cerebellum and portions of the brain stem

basilar artery bifurcates at

circle of willis to form both posterior cerebral arteries

circle of willis

only complete in 50% of patients

anterior cerebral artery

supplies frontal and parietal lobes, corpus callosum, and cavum septum pellucidum (CSP)

middle cerebral artery

supplies frontal, parietal, and temporal lobes

posterior cerebral artery

supplies temporal and occipital lobes

cerebral circulation

superficial branches spread over the surface of the brain, intracranial venous sinuses are located between the dura mater and periosteum drain cerebral blood into the internal jugular vein

most common type of stroke

ischemic stroke

what is the #1 cause of vascular disease

atherosclerosis, usually at CCA bifurcation

what can present the highest risk of TIA/stroke

ICA stenosis

embolization of atherosclerotic material break off and can

lodge into distal artery leading to cerebral ischemia

what is the strongest risk factor for a stroke

HTN, treated with medication

polycythemia vera

thickening of the blood reduced flow and may lead to ischemia distally; increased risk of thrombus/embolus formation

atherosclerosis can form

within and beneath the intima, at CCA bif (#1) or CCA origin (#2)

what is the main risk factor for a stroke

hypertension, usually treated with medication

risk factors for strokes

HTN, diabetes, hyperlipidemia, smoking, inactivity, obesity, poor nutrition

gender risk factors for strokes

more common in men, more women die

which race is at risk for strokes

African americans

transient ischemic attack (TIA)

symptoms last <24 hrs

cerebrovascular accident (CVA)

symptoms/damages last longer than 24 hours

brain infarction

insufficient blood supply to the brain due to stenosis or occlusion

subarachnoid hemorrhage

rupture of the intracranial vessels

hemispheric symptoms

specific symptoms related to right or left brain with loss of functionality

right brain controls the left side of the body

Rt ICA stenosis = LT paresis, paresthesia

left brain controls right side of the body

Lt ICA stenosis = RT paresis, paresthesia

what is the fourth leading cause of death in the US

strokes

85% of strokes are caused by

ischemia

what is the most common cause of an embolic stroke

atheroma, cardiac emboli (#2)

examination of the cranial nerves

evaluates smell, sight, muscle movement in the face, speech, hearing

motor system evaluation

body positioning, involuntary movements, muscle tone and strength

sensory exam

pain sensation (pin prick), light touch sensation (brush), position sense, stereognosis (depth perception), graphesthesia (ability to recognize numbers/letters written on skin), extinction

reflex exam

reflex hammer used to assess deep tendon reflexes

palpation

most arteries are palpated by placing two dingers over the artery

auscultation

stethoscope over at level of carotid bif to identify a bruit, can be missed if cardiac output is low. stenosis can cause a bruit

aortic valve stenosis, low hematocrit and increased cardiac output can cause

bilateral bruits

>90% stenosis does not usually cause a bruit due to

significant reduction in flow

a bruit can be missed if

cardiac output is low

blood pressure in arms should not differ more than

20mmHg or subclavian stenosis is suspected

what is the most commonly assessed artery for the presence of a bruit

carotid artery

bilateral bruits heard proximally can indicate

aortic valve stenosis

carotid sinus massage

massaged at the level of the cricoid cartilage for 5-10 seconds

carotid sinus massage will lead to

bradycardia and hypotension if carotid sinus hypersensitivity is present

carotid sinus massage should NOT be performed on patients with

an occluded carotid or recent TIA/CVA

paresthesia

tingling of skin

hemiparesis

weakness