Pharyngeal Apparatus

Question 1

Branchial clefts: aka and derived from

Answer 1

aka “branchial grooves”

Derived from ECTODERM

Question 2

Branchial arches: gives rise to and derived from

Answer 2

Derived from MESODERM

Muscles, arteries, bones, and cartilage

Question 3

Branchial pouches: derived from

Answer 3

Derived from ENDODERM

Question 4

1st Cleft (1)

Answer 4

Forms external auditory meatus

Question 5

2nd through 4th clefts

Answer 5

Forms temporary cervical sinuses…eventually obliterated

Question 6

Pathology I care about that is associated with 2nd-4th clefts

When is it noticed/becomes problematic?
Tx?

Answer 6

Persistent Cervical Sinus –> branchial cleft cyst within lateral neck.
May contain lymphoid infiltrate with prominent germinal centers that are difficult to drain. May increase in size after and URI or recent illness.
Tx: surgical excision which is difficult due to proximity to jugular veins and carotid arteries

Question 7

1st Pharyngeal Pouch: (3)

Answer 7

1. Middle ear cavity
2. Eustachian tubes
3. Mastoid air cells

Question 8

2nd Pharyngeal pouch: (1)

Answer 8

Epithelial lining of tonsils

Question 9

3rd pharyngeal pouch (2)

Answer 9

1. INFERIOR parathyroid glands

2. Thymus

Question 10

4th pharyngeal pouch (1)

Answer 10

Superior parathyroid glands