Pharyngeal Arch/Pouch/Cleft Derivatives:

Question 1

1st cleft:

Answer 1

Hearing first

- external auditory meatus

Question 2

2nd - 4th clefts:

Answer 2

Temporary cervical sinus (can persist as cyst)

Question 3

1st Pouch:

Answer 3

Hearing 1st

• eustachian tubes
• middle ear
• mastoid air cells

Question 4

2nd pouch:

Answer 4

epithelial lining of tonsils

Question 5

3rd pouch:

Answer 5

inferior parathyroid glands

thymus

Question 6

4th pouch:

Answer 6

superior parathyroid glands

Question 7

what is the defect in DiGeorge Syndrome?

Answer 7

Defective formation of 3rd and 4th pharyngeal pouches (absent thymus and parathyroids)
d/t microchromosomal deletion 11q22

Question 8

1st Arch:

Answer 8

M’s and T’s
Cartilage: meckel’s- mandibular ligament, mandible, and malleus and incus

mm- mm of mastication: lateral and Medial pterygoid, Masseter, temporalis; Mylohyoid, Tensor tympani, Tensor veli palatini, anterior 2/3 tongue

Nerve- mandibular and maxillary branches CN V

Question 9

2nd arch:

Answer 9

“S”
Cartilage: stapes, styloid process and ligament, leSSer horn of hyoid

mm: stylohyoid, stapedius, mm of facial (sounds like S) expression
nerve: CN VII (Seven)

Question 10

3rd arch:

Answer 10

“Pharyngeal”
mm- stylopharyngeous

nerve- glossopharyngeal (CN IX)

Question 11

4th and 6th arches:

Answer 11

“Cricothryoid and Larynx”
Cartilage: cartilages of larynx, cricoid and thyroid cartilages

mm: 4- pharyngeal mm and cricothyroid mm
6- rest of laryngeal mm

Nerves: CN X (4+6= X)