6. Embryology Pharyngeal Arches Clinical

Question 1

Describe a cervical cyst

Answer 1

Remnants of the cervical sinus and the 2nd groove Over time it can form a painless moveable cyst in the neck that is filled with fluid and cellular debris

Question 2

Describe a cervical sinus

Answer 2

The sinus is partially closed secondary to the second pharyngeal groove and cervical sinus to obliterate; typically occur bilaterally There is an increase in the discharge of mucus

Question 3

Which sinuses are cervical sinuses typically associated with?

Answer 3

Auricular sinuses

Question 4

What is a cervical fistula?

Answer 4

Canal that opens the tonsillar sinus to the external side of the neck due to the 2nd pharyngeal groove failing to obliterate mucus will leak onto the surface of the neck

Question 5

What is Treacher Collins syndrome?

Answer 5

autosomal dominant disorder that is secondary to a TCOF1 (Tracher Collins Franceschetti syndrome 1 gene) that encodes a protein, TREACLE in ribosome biogenesis TCOF1 is shortened in TCS which leads to the apoptosis of the cranial neural crest cells

Question 6

What is a first pharyngeal arch syndrome?

Answer 6

Insufficient migration of the neural crest cells which leads to malformation in various parts of the face

Question 7

Describe the inheritance of TCS (Treacher Collins Syndrome)

Answer 7

Autosomal dominant but it can be sporadic Typically people who have the syndrome who have children will make babies that have MORE severe deficits

Question 8

This is a first pharyngeal arch syndrome that is characterized by a small mandible, cleft palate, and defects in the eyes and ears. It occurs denovo in the patients

Answer 8

Pierre Robin sequence

Question 9

Describe the symptoms that occur in Pierre Robins sequence; what is the order?

Answer 9

Small jaw is the key symptom that inevitably causes a posterior displacement of the tongue The displacement of the tongue causes an obstruction of the full closure of the palate which results in a bilateral cleft palate

Question 10

Describe thyroid hemiagenesis. Which side is more commonly absent?

Answer 10

There is one side of the thyroid gland that is absent The left side is typically gone more often There is probably a mutation in the receptor for the thyroid stimulating hormone

Question 11

Describe DiGeorge Syndrome… What is it caused by? What does it cause physiologically? anatomically?

Answer 11

Digeorge syndrome is caused by a breakdown in the signaling of the pharyngeal arch to the endoderm in the neural crest cells causes hypoparathyroidism Patients have a shortened philtrum of the lip, low set and notched ears and cardiac abnormalities