Chapter 18 - Cerebrovascular anatomy

Question 1

Internal carotid artery branches

Answer 1

1) Caroticotympanic
2) ophthalmic
3) anterior choroidal
4) posterior communicating
5) MCA
6) ACA

Question 2

Percentage of blood from CCA that goes to ICA

Answer 2

70-80%

Question 3

External carotid artery branches

Answer 3

1) superior thyroid
2) ascending pharyngeal
3) lingual
4) facial
5) occipital
6) posterior auricular
7) superficial temporal
8) maxillary

Question 4

Which vertebral artery is usually bigger

Answer 4

Left

Question 5

Periorbital circulation contribution

Answer 5

1) Supraorbital artery
2) Frontal artery
3) Nasal artery

Question 6

Supraorbital artery track

Answer 6

Arises from ophthalmic artery
Travels anteriorly and superiorly to globe
Joins external carotid via superficial temporal artery

Question 7

Frontal artery track

Answer 7

arise from ophthalmic artery
exit orbit medially supply mid forehead
Joins superficial temporal artery

Question 8

Nasal artery track

Answer 8

Branches from frontal artery to supply the nose
Becomes angular artery
Descends along lateral border of nose
Joins facial artery

Question 9

Intracranial-extracranial anastomoses (pathways)

Answer 9

1) ICA-ECA: ophthalmic and orbital arteries, meningohypophyseal branches, caroticotympanic branches
2) occipital branch of ECA with atlantic branch of vert
3) deep cervical and ascending cervical of subclavian to vert and occipital branch of ECA
4) ECA left with right
5) dural arteries to arteries on brain surface
6) leptomeningeal collateral from meningeal border zone network to terminal cortical branches of cerebral arteries

Question 10

Bernoulli principle

Answer 10

Total fluid energy along streamline of fluid flow is constant
Velocity and pressure are inversely proportional

Question 11

Poisseuille’s law

Answer 11

Flow through a rigid tube is parabolic or laminar
Q = (P) pir^4 / 8nL

Q = flow
P = pressure
r = radius
L = length
n = viscosity of fluid

Question 12

Effect of stenosis on flow

Answer 12

1) blood change velocity resulting in Eddy currents, turbulence, vortices
2) energy loss (heat)
3) Increased frequency/velocity
4) spectral broadening