Basic Embryology

Question 1

Buccopharyngeal (oropharyngeal) membrane

Answer 1

A membrane in an early embryo separating the head end of the gut from the stomodeum

Question 2

Stomodeum

Answer 2

Primitive mouth The anterior or oral portion of the alimentary canal of an embryo

Question 3

Frontonasal prominence

Answer 3

Embryonic facial swelling of tissues that cover the surface of the forebrain

Question 4

Maxillary prominence

Answer 4

The dorsal prominence formed by bifurcation of the mandibular (first pharyngeal) arch in the embryo which joins with the medial nasal prominence in the formation of portions of the upper lip, palatal shelves & upper jaw

Question 5

Mandibular prominence

Answer 5

The ventral prominence formed by bifurcation of the mandibular (first pharyngeal) arch in the embryo, which unites ventrally with its fellow to form the lower jaw

Question 6

Nasal placodes

Answer 6

Two thickenings that appear on the frontonasal process. They are precursors to the lateral and medial prominences and eventually the nose

Question 7

Nasal pits

Answer 7

A pair of depressions formed in the developing face giving rise to the nostrils

Question 8

Medial nasal prominence

Answer 8

An embryological structure that forms the nasal bridge

Question 9

Lateral nasal prominence

Answer 9

An embryological structure that gives rise to the ala of the nose

Question 10

Intermaxillary (globular) segment

Answer 10

The lower extension of the merged medial processes which will become the philtrum of the upper lip

Question 11

Philtrum

Answer 11

A long dimple or indentation that courses from the columella down to the upper lip and is bordered by the philtral ridges on each side

Question 12

Alveolar ridge

Answer 12

The portion of the maxilla and mandible that forms the base and the bony support for the teeth; also called the alveolus or simply the gum ridge

Question 13

Palatal shelves (palatine processes)

Answer 13

Outgrowths of the maxillary process that grow into the oronasal cavity, eventually fusing with the primary palate, each other and the nasal septum to form the embryo’s hard palate

Question 14

When does a child’s cleft lip happen?

Answer 14

4th-8th week of pregnancy

Question 15

When does a child’s cleft palate happen?

Answer 15

6th-12 week of pregnancy

Question 16

If the maxillary prominence does not fuse with the lateral nasal prominence what do you get?

Answer 16

Oblique facial cleft

Question 17

What do you get if the medial nasal processes do not fuse?

Answer 17

Median cleft

Question 18

What do you get if the intermaxillary globular segment and the maxillary prominence do not fuse?

Answer 18

Cleft lip

Question 19

What do you get if the palatal shelves don’t fuse?

Answer 19

Cleft Palate

Question 20

Which five primordia form the origin of the face and mouth in the 4th week?

Answer 20

frontonasal prominence, two maxillary prominences and the two mandibular prominences

Question 21

What do you get if the mandible does not grow forward?

Answer 21

Pierre Robin Sequence