Audio Qbank – Q130 – A 33F undergoing parathyroid surgery

 

A 33-year-old woman undergoes an operation after a diagnosis of hyperparathyroidism is made. Intraoperatively, the left inferior parathyroid gland does not appear in its expected location. Which of the following embryologic events is most likely the cause of the findings in this patient?

 

  Abnormal migration of endoderm from the third pharyngeal pouch
  Absence of inductive factors in the third pharyngeal arch 
  Failure of neural crest migration through the fourth pharyngeal arch
  Incomplete formation of the fourth pharyngeal pouch
  Normal anatomic variant, albeit in a patient with hyperparathyroidism

 

Cut-to-the-chase Answer (0:39):
HY USMLE Answer (3:25):