3) Development of Head & Neck (1)

Question 1

What are the pharyngeal (branchial) arches?

Answer 1

Sequence of ridges that from in the lateral walls of the embryonic pharynx (at cranial end of neural tube)

Question 2

What are the three regions in the adult pharynx?

Answer 2

Nasal - superior to soft palate
Oral - between soft palate and larynx
Laryngeal - posterior to larynx

Question 3

How many pharyngeal arches are there?

Answer 3

5, number 1-6

Question 4

What is superior to the pharyngeal arches?

Answer 4

Frontonasal prominence which is in front of the brain

Question 5

Describe how the arches are arranged (embryonic tissues):

Answer 5

Mesenchyme core with neural crest cells
Covered by ectoderm on external surface (between arches are clefts)
Covered by endoderm on internal surface (pharyngeal pouches)

Question 6

What does each arch have associated with it?

Answer 6

Artery, nerve and cartilage bar

Question 7

What are the three regions of primitive brain?

Answer 7

Forebrain - prosencephalon
Midbrain - mesencephalon
Hindbrain - rhombencephalon

Question 8

How many pairs of cranial nerves are there?

Answer 8

12

Question 9

How are the cranial nerves classified?

Answer 9

Function and embryological origin

Question 10

Where are the cranial nerves derived from?

Answer 10

Apart from I and II, mid or hind brain

Question 11

Which cranial nerves are associated with the pharyngeal arches?

Answer 11

V, VII, IX and X

Question 12

Which cranial nerves have a relationship with the pharyngeal arch system?
(not associated with an arch)

Answer 12

CN XI (cranial accessory) and CN XII

Question 13

What is the facial skeleton derived from?

Answer 13

Frontonasal prominence and 1st pharyngeal arch

Question 14

What nerve is associated with the 1st pharyngeal arch?

And what is the sensory supply?

Answer 14

CN V, trigeminal nerve

Skin of face

Question 15

What nerve is associated with the 2nd pharyngeal arch?

And what is the sensory supply?

Answer 15

CN VII, facial nerve

Anterior 2/3rd tongue, taste buds

Question 16

What nerve is associated with the 3rd pharyngeal arch?

And what is the sensory supply?

Answer 16

CN IX, glossopharyngeal nerve

Posterior 1/3rd tongue

Question 17

What nerve is associated with the 4th pharyngeal arch?

Answer 17

CN X, vagus nerve (superior laryngeal branch)

Question 18

What nerve is associated with the 6th pharyngeal arch?

Answer 18

CN X, vagus nerve (recurrent laryngeal branch)

Question 19

Which muscles are 1st arch derivatives?

Answer 19

Muscles of mastication

digastric, mylohyoid

Question 20

Which muscles are 2nd arch derivatives?

Answer 20

Muscles of facial expression

Question 21

Which muscle is a 3rd arch derivatives?

Answer 21

Stylopharyngeus

Question 22

Which muscles are 4th arch derivatives?

Answer 22

Pharyngeal muscles (constrictors)
Cricothyroid

Question 23

Which muscles are 6th arch derivatives?

Answer 23

Intrinsic muscles of the larynx

Question 24

What skeletal structures are derived from the 1st arch?

Answer 24

Meckel’s cartilage - template for mandible + malleus and incus
Maxillary and zygomatic bones

Question 25

What skeletal structures are derived from the 2nd arch?

Answer 25

Reichert's cartilage - stapes, upper body of hyoid and lesser horn, styloid process and stylohyoid ligament

Question 26

What skeletal structures are derived from the 3rd arch?

Answer 26

Lower body of hyoid and greater horn

Question 27

What skeletal structures are derived from the 4th arch?

Answer 27

Thyroid cartilage Cricoid cartilage Epiglottis (with 3rd)

Question 28

What skeletal structures are derived from the 6th arch?

Answer 28

Arytenoid cartilage

Question 29

Which arteries are associated with the 1st and 2nd arch?

Answer 29

Arteries disappear so none

Question 30

Which arteries are associated with the 3rd arch?

Answer 30

Internal carotid arteries

Question 31

Which arteries are associated with the 4th arch?

Answer 31

Arch of aorta (L) and brachiocephalic trunk (R)

Question 32

Which arteries are associated with the 6th arch?

Answer 32

Pulmonary arch

Question 33

What is derived from the 1st pharyngeal pouch?

Answer 33

Eustachian tube, tympanic cavity and middle ear cavity

Question 34

What is derived from the 2nd pharyngeal pouch?

Answer 34

Palatine tonsil

Question 35

What is derived from the 3rd pharyngeal pouch?

Answer 35

Inferior parathyroid and thymus

Question 36

What is derived from the 4th pharyngeal pouch?

Answer 36

Superior parathyroid and C cells of thyroid

Question 37

What happens to the pharyngeal clefts?

Answer 37

1st is all that remains as 2nd arch grows down to cover others

Question 38

What does the 1st pharyngeal cleft form?

Answer 38

External auditory meatus of ear

Question 39

What can occur if clefts or cervical sinus remains?

Answer 39

Branchial cysts or fistulae

Question 40

Where are cysts likely to form?

Answer 40

Anterior border of sternocleidomastoid