W2 and W4 - Paranasal Sinus, Brain Vasculature

BBB (Blood Brain Barrier)

• the brain capillary specialization that restricts the movement of certain molecules from the bloodstream into surrounding neural tissue

• therefore, a healthy BBB prevents a sig. amount of CM into brain tissues during CM studies

Main Vessels that Supply the Brain

• internal carotid arteries (ICA)

• vertebral arteries 

Venous System

SVC → Brachiocephalic vein → Subclavian vein → IJV, EJV, vertebral vein

Bifurcations from the Aortic Arch

• Brachiocephalic (RT)

  • RT subclavian → RT vertebral

  • RT common carotid → RT ICA and ECA

• LT common carotid → LT ICA and ECA

• LT subclavian → LT vertebral

pathway of the L/R vertebral arteries  

vertebral arch → transverse foramina → foramen magnum → L/R vertebral arteries unite to form the basilar artery

Anterior and Middle Vasculature is supplied by

ICA

common carotid artery bifurcation level

C4/5

external carotid artery supplies the

face, scalp, neck, tongue

main branches of the internal carotid artery

• L/R ophthalmic arteries

• L/R anterior cerebral arteries

• L/R middle cerebral arteries 

what structures does internal carotid artery supply

brain lobes, orbital structures 

Anterior CA supplies the

ant. frontal lobe, medial parietal lobe

Middle CA supplies the

• lateral surface of the cerebrum, insula, ant/lat temporal lobes, basal nuclei

• largest CA

posterior brain vasculature is supplied by the

basilar artery

pontine vessels 

• part of the post. brain vasculature

• small branches that supply the pons 

posterior brain vasculature main branches

• post/inf cerebellar artery

• ant/inf cerebellar artery

• sup cerebellar artery

• post cerebral artery

circle of willis (COW)

• formed by the ant/post CAs, ant/post communicating arteries, and ICA

• important collateral pathway allowing blood flow between the cerebral hems in the event of arterial blockage

dural sinuses

where all venous blood from the head drains into before getting emptied into the internal jugular veins

types of dural sinuses

• superior sagittal

• inferior sagittal

• straight

• transverse

• sigmoid

• cavernous

• petrosal sinus (sup, inf)

superior sagittal sinus drainage

confluence of sinus

inferior sagittal sinus pathway

joins with the great cerebral vein to form the straight sinus 

straight sinus drainage

transverse sinus

transverse sinus drainage

sigmoid sinus

sigmoid sinus pathway

joins the jugular bulbs, exits the skull thru the jugular foramina and descends down as the internal jugular veins

cavernous sinus

drains into sup and inf petrosal sinuses 

petrosal sinuses drainage

sigmoid

torcular herophili / confluence of sinuses

junction of the superior sagittal, straight, and transverse sinuses

cavernous sinus receives blood from

the superior and inferior ophthalmic veins

middle CA

27?

27 = basilar

32?

32 = posterior CA

29?

anterior CA