embryology

Question 1

1st branchial cleft

Answer 1

external auditory meatus

Question 2

2nd-4th branchial clefts

Answer 2

temporary cervical sinuses
(obliterated by proliferation of 2nd arch mesenchyme)

persistent cervical sinus –> branchial cleft cyst w/in lateral neck, does not move w/ swallowing

Question 3

1st branchial arch

Answer 3

meckel cartilage: mandible, malleus, incus, spheno-mandibular ligament

muscles of mastication - temporalis, masseter, lateral & medial ptyerogoids. mylohyoid. anterior belly digastric. tensor tympani. tensor veli palatini. ant 2/3 tongue

CN V2 & V3

Question 4

2nd branchial arch

Answer 4

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

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

CN VII

Question 5

3rd branchial arch

Answer 5

cartilage: greater horn of hyoid

stylopharyngeus

CN IX

Question 6

4th-6th branchial arches

Answer 6

cartilages: thyroid, cricoid, arytenoids, corniculate, cuneiform

4th: most pharyngeal constrictors, cricothyroid, levator veli palatini
6th: all intrinsic mm. of larynx (except cricothyroid)

4th: CN X (superior laryngeal branch)
6th: CN X (recurrent laryngeal branch)

Question 7

1st aortic arch

Answer 7

part of maxillary artery (branch of external carotid)

Question 8

2nd aortic arch

Answer 8

stapedial artery

hyoid artery

Question 9

3rd aortic arch

Answer 9

common carotid

proximal internal carotid

Question 10

4th aortic arch

Answer 10

L: aortic arch
R: proximal R subclavian

Question 11

6th aortic arch

Answer 11

proximal pulmonary arteries

ductus arteriosus