Embryology

Question 1

what are the three components of the pharyngeal apparatus?

Answer 1

1. core pharyngeal arch (mesenchymal tissue)
2. external pharyngeal cleft (ectoderm)
3. internal pharyngeal pouch (endoderm)

Question 2

what separates arches?

Answer 2

clefts and pouches

Question 3

what is each arch associated with?

Answer 3

artery
nerve
vein

Question 4

what does the pharyngeal arch consist of?

Answer 4

mesenchyme
neural crest cells (skeletal components)
cranial nerve component
artery

Question 5

arch 1 cranial nerve

Answer 5

trigeminal nerve (CNV2 and V3)

Question 6

arch 2 cranial nerve

Answer 6

facial nerve (CNVII)

Question 7

arch 3 cranial nerve

Answer 7

glossopharyngeal nerve (CNIX)

Question 8

arch 4 and 6 cranial nerve

Answer 8

vagus CNX
4 is superior laryngeal branch
6 is recurrent laryngeal branch

Question 9

what causes cervical cysts and fistulas?

Answer 9

the 2nd-4th cleft should lose contact and form the cervical sinus which then disappears

Question 10

where are cervical cysts and fistulas seen?

Answer 10

anterior border of sternocleidomastoid

enlarge in childhood

Question 11

where does the nasolacrimal groove lie?

Answer 11

between maxillary and lateral nasal proinence

Question 12

define cleft lip

Answer 12

malunion between primary palate and upper limb

Question 13

define cleft palate

Answer 13

floating of the primary palate, potential for nasolacrimal celft