Lecture 50 Embryology of the Face

Question 1

Describe the five anatomical regions of the human face.

Answer 1

Forehead, eyes/orbit, nose/nasal complex, “cheeks”, and mouth

Question 2

Which organisms have a face?

Answer 2

most vertebrates

Question 3

What bone comprises a majority of the forehead?

Answer 3

frontal bone

Question 4

Name the seven bones that form the orbital area.

Answer 4

Frontal, Maxillary, Zygomatic, Sphenoid, Ethmoid, Lacrimal, and Palatine

Question 5

Two nasal bones, the frontal process of the maxilla (externally) and the ethmoid and superior concha (internally) form which anatomical region of the human face?

Answer 5

Nose and nasal complex

Question 6

What bones form the “cheek” area?

Answer 6

largely, the maxillae and zygoma (laterally) and the mandible (inferiorly)

Question 7

The mandible (lower jaw) and maxilla (upper jaw) form what anatomical region of the human face?

Answer 7

Mouth region

Question 8

Describe the osteology of the human face.

Answer 8

Bones are formed via endochondral ossification (largely basicranial bones) and via intramembranous ossification (mostly facial and vault bones)

Question 9

Major innervation of the face comprises sensory, mostly from CN _____ and motor from CN _____ and CN ____ for masticatory muscles.

Answer 9

V
VII
V

Question 10

Name the six major facial muscles

Answer 10

Orbicularis oris, Orbicularis oculi, buccinators, platysma, fronto-occipitalis, zygomaticus major

Question 11

Which two branchial arches are mostly concerned with the embryological formation of the face?

Answer 11

branchial arches 1 and 2

Question 12

Name the five embryological facial prominences.

Answer 12

unpaired frontonasal prominence, paired maxillary prominences, paired mandibular prominences

Question 13

What is the primordium of the mandible?

Answer 13

Meckel’s cartilage, which is replaced by membranous bone

Question 14

What are the four functions of the human face?

Answer 14

Focal point for cranial senses, air intake, food intake, and crucial emotional signaling

Question 15

The trigeminal nerve (CN V) via its three divisions (____, ____, and _____) carries the majority of ____ sensation from the face. The _____ (ventral rami ____, ____) carries sensation from the region of the angle of the jaw.

Answer 15

Opthalmic (V1), Maxillary (V2), Mandibular (V3)
GSA
Great auricular nerve
C2,C3

Question 16

Muscles of the face are mostly innervated by SVE fibers in what nerve? What are the exceptions of this statement?

Answer 16

Facial Nerve (CN VII)
The levator palpebrae superioris is innervated by CN III (GSE) and the masticatory muscles, including the mylohyoid and anterior belly of the digastric by SVE fibers of CN V

Question 17

Name the role of the muscles of the face.

Answer 17

controlling orifices and apertures for communication

Question 18

What is the primary function of of the orbicularis oculi and what nerve is it innervated by?

Answer 18

closes the eyes

CN VII

Question 19

The five prominences appear around what structure and by when?

Answer 19

the prominences appear by early week four by mesenchymal proliferation and appear around the stomodeium (primitive mouth)

Question 20

Name the derivatives of the frontonasal prominence.

Answer 20

formation of the nostrils/nose

Question 21

What prominence will derive the maxilla, upper cheeks, upper lip, philtrum, and primary and secondary palates?

Answer 21

paired maxillary prominences

Question 22

Name the derivatives of the paired mandibular prominences.

Answer 22

Lower cheek, lower lip, and mandible

Question 23

Abnormal development of the primary and secondary palates can lead to what?

Answer 23

Cleft lip (CL), cleft palate (CP), or combinations (CLP)

Question 24

Lip/palate development occurs sequentially, with lips first at ____ weeks and then primary palate by week _____ with secondary palate later at _____ weeks.

Answer 24

4-8
6
6-12

Question 25

CLP, CP, and CL arise from failure of what processes to occur?

Answer 25

Failure of the medial or lateral nasal processes to fuse with the medial aspects of the maxillary processes and/or failure of the primary palate to fuse with aspects of the secondary palate and/or failure of the right and left portions of the secondary palate to close

Question 26

The causes of Cl, CP, and CLP are described as what?

Answer 26

both syndromic and non-syndromic forms; causes are multifactorial and involve genetics, environmental factors, and teratogens

Question 27

What are the physical effects of CL, CP, and CLP in children?

Answer 27

difficulty with eating and swallowing

vanity concerns