24 - pharyngeal arches derivatives

1. the muscular derivatives of the first pharyngeal arch are?

1. the muscles of mastication
2. masseter
3. temporalis
4. pterygoids
5. mylohyoid
6. tensor tympani
7. tensor veli palatini
8. anterior belly of digastric

answer: all of them are true . masseter , temporalis and pterygoids include the muscles of mastication . all these muscles have a single nerve supply by the mandibular branch of the trigeminal nerve .

2. the skeletal derivatives of the first pharyngeal arch are?

1. meckel’s cartilage
2. part of malleus
3. part of incus
4. anterior malleolar ligament
5. sphenomandibular ligament

answer: all of them are true . all of the above mentioned are skeletal derivatives of the first pharyngeal arch .

3. the muscular derivatives of the second pharyngeal arch are?

1. platysma
2. stylohyoid
3. posterior belly of digastric
4. muscles of facial expression
5. auricular muscles
6. stapedius
7. occipito frontalis

answer: all of them are true . all the above mentioned are infact the muscular derivatives of the second pharyngeal arch . facial nerve supplies all these muscles and so is the main nerve which supplies the second pharyngeal arch .

4. the skeletal derivatives of the second pharyngeal arch are?

1. part of malleus
2. part of incus
3. stapes
4. stylohyoid ligament
5. styloid process
6. lesser cornu of the hyoid
7. upper body of hyoid bone

answer: all the above .

5. which of the following statements are true about the third pharyngeal arch ?

1. the muscular derivative of the third pharyngeal arch is the stylopharyngeus
2. the main nerve supply of the third pharyngeal arch is the glossopharyngeal nerve
3. the skeletal derivative of the third pharyngeal arch is the greater cornu of the hyoid and the lower body of the hyoid bone .
4. all are true

answer: d . all are true .

6. which of the following statements are true ?

1. the fourth arch forms the cricothyroid muscle with components of the fifth arch
2. the nerve supply of the cricothyroid muscle is the superior or external laryngeal nerve .
3. superior laryngeal nerve is a branch of the vagus nerve
4. the sixth pharyngeal arch forms all the intrinsic muscles of the larynx except the cricothyroid

answer : all are true .

7. find the true statements ?

5. the nerve of the sixth pharyngeal arch is the recurrent laryngeal nerve
6. recurrent laryngeal nerve is also a branch of the vagus nerve
7. the skeletal derivative of the fourth pharyngeal arch is thyroid cartilatge
8. the skeletal derivative of the sixth pharyngeal arch is the arytenoids cartilage
9. the fifth pharyngeal arch combines with the fourth arch to form various structures but as such is less significant .

answer: all are true .