Pharyngeal Apparatus: Arches

Question 1

Pharyngeal arches

Answer 1

6 curved cylindrical thickenings on each side of pharyngeal duct

Question 2

Components

Answer 2

Each consists of a mesodermal core covered on the outside by surface ectoderm and on inside by endoderm, each has its own nerve and atrial supply

Question 3

Course of arch contents

Answer 3

Paraxial and lateral plate mesoderm neural crest cells

Question 4

Time of appearance

Answer 4

1. Appear in 4th and 5th weeks of development
2. Cranial arches precede caudal ones in development and prominence

Question 5

Fate (derivatives)

Answer 5

1. Skeletal and Ligamentum derivates
2. Muscular derivatives
3. Nerve

Question 6

1st arch

Answer 6

1. Mandibular arch
2. Consists of maxillary and mandiblular processes

Question 7

2nd arch

Answer 7

Hyoid arch

Question 8

1st arch: skeletal and ligamentous derivatives

Answer 8

1. Maxillary process
2. Mandibular process
3. Ligaments

Question 9

Maxillary process

Answer 9

Gives
1. Maxilla
2. Zygomatic
3. Part of temporal bones

Question 10

Mandibular process

Answer 10

Gives:
Meckel’s cartilage
1. Dorsal end:
form malleus and incus
2. Ventral enemy
Forms mandible part
3. Cartilage rest degenerates
4. Most of mandible formed by membranous ossification

Question 11

1 arch ligaments

Answer 11

1. Sphenomandibular ligament
2. Malleus anterior ligament
   Both are formed from perichondrium of degenerated cartilage

Question 12

1st arch: muscular derivatives

Answer 12

1. Muscles of mastication
2. Mylohyoid
3. Anterior belly digastric
4. Tensor palati
5. Tensor tympani

Question 13

1 arch nerve

Answer 13

Trigeminal nerve

Question 14

2nd arch: skeletal and ligamentous derivatives

Answer 14

1. Reichert’s cartilage
2. Ligaments

Question 15

Reichert’s cartilage

Answer 15

1. Dorsal end:
   Form stapes and styloid process
2. Ventral end:
   Forms lesser horn and hyoid body upper part
3. Cartilage rest degenerates

Question 16

2nd arch ligaments

Answer 16

Stylohyoid ligament is formed from perichondrium of degenerated cartilage

Question 17

2nd arch: muscular derivatives

Answer 17

1. Muscles of face
2. Occipitofrontalis
3. Platysma
4. Stylohyoid
5. Posterior belly digastric
6. Stapedius

Question 18

2nd arch: nerve

Answer 18

Facial nerve

Question 19

3rd arch: skeletal and ligamentous derivatives

Answer 19

Greater horn and hyoid body lower part

Question 20

3rd arch: muscles

Answer 20

Stylopharyngeus

Question 21

3rd arch:nerve

Answer 21

Glossopharyngeal nerve

Question 22

4th arch: skeletal and ligamentous derivatives

Answer 22

Thyroid cartilage upper part

Question 23

4th arch: muscles

Answer 23

1. Extrinsic laryngeal muscles (cricothyroid)
2. Pharyngeal
3. Levator palati muscles

Question 24

4th arch: nerve

Answer 24

Superior laryngeal and pharyngeal branches of vagus nerve

Question 25

6th arch: skeletal and ligamentous derivatives

Answer 25

Thyroid cartilage lower part and laryngeal cartilages rest

Question 26

6th arch: muscles

Answer 26

Intrinsic laryngeal muscles

Question 27

6th arch: nerves

Answer 27

Recurrent laryngeal branch of vagus nerve

Question 28

5th arch

Answer 28

Either never forms in human or forms and rapidly regresses