Lecture 9 : Pharyngeal Arches

Question 1

The pharyngeal apparatus is made up of 4 components:

Answer 1

1. arches
2. grooves/clefts
3. membranes
4. pouches

Question 2

Each arch is lined externally by….

Answer 2

ectoderm

Question 3

Each arch is lined internally by…

Answer 3

endoderm

Question 4

The first arch forms a … and … process

Answer 4

maxillary and mandibular

Question 5

The maxillary process from arch 1 forms: (3)

Answer 5

Maxillary bones
Zygomatic bones
Vomer

Question 6

The mandibular process from arch 1 forms the… and…

Answer 6

mandible and squamous portion of temporal bone

Question 7

Skeletal elements of arch 1

Answer 7

1. anterior ligament of malleus
2. malleus and incus
3. sphenomandibular ligament
4. Meckel cartilage

Question 8

Skeletal elements of arch 2

Answer 8

1. stapes
2. styloid process
3. stylohyoid ligaments
4. lesser cornu of hyoid bone
5. Reichert cartilage

Question 9

Skeletal elements of arch 3

Answer 9

1. body of hyoid bone

2. greater cornu (horn) of hyoid bone

Question 10

Skeletal elements of 4th and 6th arch

Answer 10

1. Thyroid cartilage

2. cricoid cartilage

Question 11

1st arch muscles

Answer 11

1. MOM (temporalis, masseter lateral and medial pterygoid)
2. Mylohyoid
3. anterior belly os digastric
4. Tensor tympani and veli palatini

Question 12

1st arch muscles are all innervated by…

Answer 12

CNV (trigeminal, V2 and V3)

Question 13

2nd arch muscles

Answer 13

1. Facial expression
2. Stapedius
3. Posterior belly of digastric
4. Stylohyoid

Question 14

2nd arch muscles are all innervated by…

Answer 14

CNVII (facial)

Question 15

3rd arch muscle

Answer 15

Stylopharyngeus m.

Question 16

The 3rd arch muscle, stylopharyngeus m. is innervated by

Answer 16

CNIX (glossopharyngeal)

Question 17

4th arch muscles

Answer 17

1. pharyngeal constrictor mm.
2. Levator veli palatini m.
3. Cricothyroid m.

Question 18

4th and 6th arch muscles are innervated by

Answer 18

CNX (Vagus)

Question 19

6th arch muscle

Answer 19

intrinsic mm. of larynx

Question 20

Anterior 2/3 of tongue (from 1st arch) is innervated by

Answer 20

CNV-trigeminal, V3 sensory

CNVII-facial- taste

Question 21

Posterior 1/3 (mostly from 3rd arch) is innervated by

Answer 21

CNIX-glossopharyngeal- sensory and taste

Question 22

The epiglottis is innervated by

Answer 22

CNX-vagus-sensory and taste

Question 23

Pouch 3 derivatives- dorsal buds become… and ventral buds become…

Answer 23

dorsal buds- inferior parathyroid glands

ventral buds- fuse together at midline forming thymus

Question 24

Pouch 4 derivatives- dorsal buds become… and ventral buds become…

Answer 24

dorsal buds- superior parathyroid glands

ventral buds- ultimopharyngeal body

Question 25

The 1st pharyngeal groove/cleft becomes the

Answer 25

external acoustic meatus

Question 26

The 2nd-4th pharyngeal grooves/clefts become…

Answer 26

cervical sinus which becomes the cervial vesicle which eventually closes

Question 27

Remnants of a lateral cervical sinus/vesicle or 2nd groove can form a fluid filled cyst in the neck called

Answer 27

a cervical branchial cyst which often develops just below angle of mandible