Aortic arches

Question 1

describe the fate of 1st, 2nd and 3rd pharyngeal arch arteries

Answer 1

• First: Maxillary artery
• Second: Hyoid and stapedia artery
• Third: Common carotid artery, external carotid and proximal part of internal carotid artery (distal part of internal carotid a. forms from dorsal aortae)

Question 2

describe the derivatives of the 4th and 6th

Answer 2

• 4th:
  
  • Left: part of the arch of aorta
  • Right: proximal part of the right subclavian artery
• 6th:
  
  • Proximal part
    
    • proximal part of pulmonary arteries
  • Distal part
    
    • left side: ductus arteriosus
    • right side: degenerates

Question 3

describe the development of the arch of the aorta

Answer 3

• aortic sac, left 4th pharyngeal arch artery

Question 4

describe a double aortic arch

Answer 4

• due to persistence of the distal part of the right dorsal artery
  
  • two arteries wrap around esophagus and trachea

Question 5

describe a right arch of aorta

Answer 5

• right arch of the aorta is due to a persistence of the right dorsal aorta while the distal part of the left dorsal aorta involutes
  
  • if there is a retroesophageal component the right arch of the aorta and the ligamentum arteriosum (from the DA) may form a constricting rign around esophagus and trachea

Question 6

describe the development of subclavian arteries

Answer 6

• Left:
  
  • left 7th cervical intersegmental artery
• Right:
  
  • right 4th pharyngeal arch artery, dorsal aorta and the right 7th cervical intersegmental artery

Question 7

describe an anomalous right subclavian artery

Answer 7

• abnormal involution of right 4th pharyngeal artery
• persistent distal part of right dorsal artery

Question 8

describe the right and left recurrent laryngeal nerves

Answer 8

• right recurrent laryngeal nerve loops around right subclavian artery
• left recurrent laryngeal nerve loops around aortic arch distal to ductus arteriosus

Question 9

describe the fate of the 4 shunts

Answer 9

• umbilican vein –> ligamentum teres
• ductus venosus –> ligamentum venosum
• oval foramen –> oval fossa
• ductus arteriosus –> ligamentum arteriosus

Question 10

describe PDA

Answer 10

• occurs more frequently in females than males
• most common birth defect associated with maternal rubella infection in early pregnancy
• other causes:
  
  • premature infants
  • high altitude
  • hypoxia

Question 11

name the types of coarctation of the aorta

Answer 11

• aortic constriction
• preductal: proximal to ductus arteriosus
• juxtaductal: entrance to ductus arteriosus (90%)
• postductal: distal to ductus arteriosus
• 15-20% of Turner syndrome patients

Question 12

describe the collateral circulation in coarctation of aorta

Answer 12

• subclavian –> internal thoracic –> anterior intercostal –> posterior intercostal –> descending aorta
• enlarged intercostal arteries
• weak lower limb pulse
  
  • babies have blue lower limbs
• rib notching of inferior 3rd-8th ribs