Facial, Skull, & Sockets

Question 1

Neurocranium Components and origins

Answer 1

Membranous neurocranium (flat bones)
Cartilaginous neurocranium (base of skull)
Partly from NCC (ectoderm) and somitomeres (mesoderm)

Question 2

Viscerocranium forms…

Answer 2

Neural crest cells make up facial bones:

maxilla, mandible, zygomatic, vomer, palatine, lacrimal, nasal

Question 3

Brachycephaly

Answer 3

Coronal suture fails

Stout skull

Question 4

Frontonasal Prominence Development

Answer 4

Optic placode and Auricular hillicks formed ( 3 hillocks from arch 1 & 2)
Rapid brain development

Question 5

Fontanelles

Answer 5

Newborn has ~44 skull bones

6 fontanelles

Question 6

Lateral Brain Development

Answer 6

Optic placode moves anteriorly

Auricular hillocks and external auditory meatus migrate to otic placode

Question 7

Cloverleaf

Answer 7

Most cranial sutures

Question 8

Chondrocranium Bones

Answer 8

Cranial base: occipital, ethmoid, sphenois, temporal petrosal, nasal
Cartilage development begins at midline

Question 9

Neurocranium forms…

Answer 9

Neural crest cells make: Temporal squamos, sphenoid, ethmoid, frontal
Mesoderm forms: Temporal petrosal, occipital, parietal

Question 10

Plagiocephaly

Answer 10

Unilateral coronal and lamboid suture fail

Asymmetric flattening of the side of the skull

Question 11

List all the structures formed by the Medial prominence

Answer 11

Philtrum, medial maxilla, primary palate, medial nasal

Question 12

Endochondral Ossification

Answer 12

Cartilage model precursor:
Hyaline cartilage used as template
Mesenchymal osteoblasts form 2 ossification centers –> Osteoid deposited in place of cartilage model
Begins in 2nd trimester–> ends early adulthood
Depends on prescence of epiphyseal cartilage

Question 13

Scaphocephaly

Answer 13

Sagittal suture fails

Long and narrow

Question 14

Upper lip formation

Answer 14

Medial nasal and maxilla prominence

Question 15

Craniosynostosis

Answer 15

Premature closure of sutures
1:25000
Many due to mutations in FGFRs

Question 16

Nasolacrimal/Nasooptic groove formation

Answer 16

Medial migration of frontalnasal process

Question 17

Bones formed by Intramembranous Ossification

Answer 17

Flat bones of face, mandible, clavicle

Question 18

Cranishisis

Answer 18

Cranial vault fails to form

Question 19

Bones formed by Endochondral Ossification

Answer 19

Long bones, bones of extremeties, vertebral, ethmoid, sphenoid

Question 20

All bones are Mesoderm except…

Answer 20

Viscerocranium

Temporal squamos, sphenoid, ethmoid, frontal boanes, hyoids

Question 21

NCC come from

Answer 21

NCC form from developing neural tube and migrate posterior neural tube to anterior

Question 22

Intramembranous Ossification

Answer 22

Absence of cartilage model
Mesenchymal cells aggregate and proliferate –> differentiate into osteoblasts and secrete osteoid at multiple centers of ossification –> Osteoid is mineralized

Question 23

Philtrum formation

Answer 23

Medial and frontonasal prominence