Embryology

Question 1

What does the 1st aortic arch give rise to?

Answer 1

External carotid and maxillary as.

Question 2

What does the 2nd aortic arch give rise to?

Answer 2

Stapedial a.

Question 3

What does the 3rd aortic arch give rise to?

Answer 3

Common and internal carotid as.

Question 4

What does the aortic sac give rise to?

Answer 4

Base of aortic arch and brachiocephalic a.

Question 5

What does the 4th aortic arch give rise to?

Answer 5

L. = medial aortic arch
R. = proximal R. subclavian a.

Question 6

What does the 5th aortic arch give rise to?

Answer 6

Nothing, completely degenerates

Question 7

What does the 6th aortic arch give rise to?

Answer 7

Pulmonary as.
L. = distal ductus arteriosus
R. = degenerates

Question 8

What does the 7th aortic arch give rise to?

Answer 8

Intersegmental as.
L. = entire subclavian a.
R. = distal R. subclavian a.

Question 9

What does the dorsal aorta give rise to?

Answer 9

L. = descending aorta
R. = portion of R. subclavian

Question 10

What does the sinus venosus give rise to?

Answer 10

L. horn = coronary sinus

R. horn = crista terminalis and sunus venosus of R. atrium

Question 11

What are the segments of the IVC and what do they come from?

Answer 11

Hepatic segment = R. vitelline/Hepatic vs.
Prerenal segment = R. subcardinal vs.
Renal segment = Subcardinal/Supracardinal vs.
Postrenal segment = R. supracardinal vs.

Question 12

What do the anterior cardinal veins become?

Answer 12

R. = internal jugular and SVC
L. = L. brachiocephalic v.

Question 13

What do the posterior cardinal veins become?

Answer 13

All degenerate except for root of azygos v.

Question 14

What does the vitelline veins become?

Answer 14

R. = hepatic v.

R. and L. = portal v.

Question 15

What do the umbilical veins become?

Answer 15

R. = degenerates
L. = ductus venosus/attachment to placenta