Arch derivatives

Question 1

1st aortic arch

Answer 1

Part of maxillary artery (branch of external carotid)

Question 2

2nd aortic arch

Answer 2

Stapedial artery and hyoid artery

Question 3

3rd aortic arch

Answer 3

Common carotid artery

Proximal part of internal carotid artery

Question 4

4th aortic arch

Answer 4

On L aortic arch, on right- proximal part of R subclavian artery

Question 5

6th aortic arch

Answer 5

Proximal part of pulmonary arteries and (on left only) ductus arteriosus)

Question 6

Branchial clefts

Answer 6

Derived from ectoderm. Also called branchial grooves

Question 7

Branchial arches

Answer 7

Derived from mesoderm (muscles, arteries) and neural crest (bones, cartilage)

Question 8

Branchial pouches

Answer 8

Derived from endoderm

Question 9

1st branchial cleft

Answer 9

External auditory meatus

Question 10

2nd-4th branchial clefts

Answer 10

Temporary cervical sinuses that are then obliterated

Question 11

Persistent cervical sinus

Answer 11

Branchial cleft cyst within lateral neck, anterior to SCM. Immobile during swallowing.

Question 12

1st branchial arch cartillage

Answer 12

Maxillary process (Maxilla, zygomatic bone)
Mandibular process (Meckel cartilage--> mandible, malleus and incus, sphenomandibular ligament)

Question 13

1st branchial arch muscles

Answer 13

Muscles of mastication (temporalis, masseter, lateral and medial pterygoids), mylohyoid, anterior belly of digastric, tensor tympani, tensor veli palatini

Question 14

1st branchial arch nerves

Answer 14

CN V2 and V3 (maxillary and mandibular)

Question 15

Pierre Robin sequence

Answer 15

Micrognathia, glossoptosis, cleft palate, airway obstruction. 1st branchial arch dysfunction.

Question 16

Treacher Collins syndrome

Answer 16

Neural crest dysfunction–> mandibular hypoplasia, facial abnormalities. 1st branchial arch dysfunction.

Question 17

2nd branchial arch cartilage

Answer 17

Reichert cartilage: stapes, styloid process, lesser horn of hyoid, stylohyoid ligament.

Question 18

2nd branchial arch muscles

Answer 18

Muscles of facial expression, stapedius, stylohyoid, platysma, posterior belly of digastric

Question 19

2nd branchial arch nerves

Answer 19

CN VII

Question 20

3rd branchial arch cartilage

Answer 20

Greater horn of hyoid

Question 21

3rd branchial arch muscles

Answer 21

Stylopharyngeus

Question 22

3rd branchial arch nerves

Answer 22

CN IX

Question 23

4th-6th arches (cartilage)

Answer 23

Arytenoids, cricoid, corniculate, cuneiform, thyroid (Used to sing and ACCCT)

Question 24

4th branchial arch muscles

Answer 24

Most pharyngeal constrictors, cricothyroid, levator veli palatini

Question 25

6th branchial arch muscles

Answer 25

All intrinsic muscles of larynx except cricothyroid

Question 26

4th branchial arch nerves

Answer 26

CN X (superior laryngeal branch)

Question 27

6th branchial arch nerves

Answer 27

CN X (recurrent laryngeal branch)

Question 28

What forms posterior 1/3 of tongue?

Answer 28

Arches 3 and 4

Question 29

1st branchial pouch

Answer 29

Middle ear cavity, eustachian tube, mastoid air cells. Contributes to endoderm-lined structures of ear

Question 30

2nd branchial pouch

Answer 30

Epithelial lining of palatine tonsil

Question 31

3rd branchial pouch

Answer 31

• -Dorsal wings–> Inferior parathyroid

- -Ventral wings–> thymus

Question 32

4th branchial pouch

Answer 32

• -Dorsal wings–>superior parathyroids

- -Ventral wings–> ultimobranchial body–> parafollicular (C) cells of thyroid