Head & Neck Embryology

Question 1

What embryological structure forms the mandible?

Answer 1

-1st pharyngeal arch (ventral)

Question 2

What embryological structure forms the maxilla, zygomatic, and parts of the temporal bones?

Answer 2

-1st pharyngeal arch (dorsal)

Question 3

What embryological structure forms the malleus and incus?

Answer 3

-Ventral 1st pharyngeal arch

Question 4

What embryological structure forms the stapes, styloid process, and upper part of the hyoid bone?

Answer 4

2nd pharyngeal arch

Question 5

Which pharyngeal arch does the trigeminal nerve develop in?

Answer 5

1st pharyngeal arch

Question 6

Which pharyngeal arch does the facial nerve develop in?

Answer 6

2nd pharyngeal arch

Question 7

Which pharyngeal arch does the Glossopharyngeal nerve develop in?

Answer 7

-3rd pharyngeal arch

Question 8

What embryological structure forms the middle ear and Eustachian tube?

Answer 8

1st pharyngeal POUCH

Question 9

What simplified structures do pharyngeal pouches 1-4 develop into?

Answer 9

1st = ear (middle eary, Eustachian tube)

2nd = Tonsil Fossa

3rd = inferior parathyroid and thymus

4th = Superior parathyroid and calcitonin cells

Question 10

What embryological structure forms the ear (auditory canal)?

Answer 10

1st Pharyngeal cleft

Question 11

What simplified structures do pharyngeal arches 1-4 develop into?

Answer 11

1st – JAW (maxilla, mandible, muscles of mastication, trigeminal nerve)

2nd –FACE (muscles of facial expression, facial nerve)

3rd – “TONGUE”– glossopharyngeal = taste from posterior 1/3 of tongue

4th and 6th:LARYNX (laryngeal branches of the vagus)

Question 12

What happens if there is an abnormal connection between a branchial cleft and pouch?

Answer 12

-Formation of a branchial cleft sinus (fistula)

***2nd cleft most common

Question 13

Describe the path of a 2nd branchial cleft sinus.

Answer 13

• orifice on anterior border of SCM

- travels through carotid bifurcation to tonsillar fossa

Question 14

What embryological structure develops into the mouth?

Answer 14

Stomodeum

Question 15

What are the two layers of the optic cup?

Answer 15

pigmented & Neural

Question 16

What ectodermal thickening develops into the eye?

Answer 16

-Optic placode

Question 17

What embryological structure forms the inner ear?

Answer 17

-Otic placode (ectoderm)

Question 18

Which portion of the otic placode forms the sacule and cochlear duct?

Answer 18

-Ventral

Question 19

Which portion of the otic placode forms the semicircular canals?

Answer 19

-Dorsal

Question 20

What embryological structure forms the nasolacrimal duct?

Answer 20

-nasolacrimal groove

Question 21

What embryological structure forms the protrusion of the nose?

Answer 21

-Medial growth of the maxillary prominence

Question 22

What happens if there is no fusion of the nasolacrimal groove?

Answer 22

-Facial clefts

Question 23

What embryological structure forms the upper lip?

Answer 23

-Medial nasal prominences and the maxillary prominence

Question 24

What embryological structure forms thesecondary palate?

Answer 24

-palatine shelves fuse in the midline and with primary palate (anterior)

Question 25

Which branchial arch forms the body of the tongue?

Answer 25

-1st arch

Question 26

Which branchial arch forms the root of the tongue?

Answer 26

-3rd

Question 27

Which branchial arch forms the epiglottis?

Answer 27

-4th

Question 28

Which nerve carries taste and sensory information from the epiglottis?

Answer 28

-Vagus

Question 29

What embryological structure forms the thyroid gland?

Answer 29

-Thyroid diverticulum at end of foramen cecum

Question 30

What forms in failure of obliteration of the thyroglossal duct?

Answer 30

-Thyroglossal duct cyst

Question 31

From where does the palatine tonsil drive embryologically?

Answer 31

-3rd pharyngeal arch

**tonsilar fossa is from 2nd pharyngeal POUCH