Fetal Face and Neck

Question 1

What are the three facial prominences that begin to evolve by 6 menstrual weeks?

Answer 1

Frontonasal, Maxillary, Mandibular

Question 2

What structures develop from the pharyngeal pouches?

Answer 2

• Pharyngotympanic tube
• Middle ear cavity
• Palatine tonsil
• Thymus
• Four parathyroid glands
• Ultimobranchial bodies of the thyroid gland

Question 3

What do pharyngeal arches produce?

Answer 3

• Cartilage
• Bone
• Nerves
• Muscles
• Glands
• Connective tissue of the face and neck

Question 4

At what menstrual weeks does the bony structure of the face begin to form?

Answer 4

6-7 menstrual weeks

Question 5

When does ossification of the mandible, maxilla, and orbits begin?

Answer 5

8-9 menstrual weeks

Question 6

At what stage can sonographically see the bony structures of the face?

Answer 6

11-12 menstrual weeks

Question 7

By what menstrual weeks is the face well defined?

Answer 7

14-16 menstrual weeks

Question 8

What structures develop by the 12th menstrual week?

Answer 8

• Pharyngeal arches and grooves into face, nasal cavities, mouth, tongue, larynx, pharynx, neck fascia
• Salivary and thyroid glands
• Skeletal, neural, muscular and vascular neck structures
• Somites into muscle, cartilage, tendons endothelial cells, dermis

Question 9

What can be consistently identified from 12 weeks of gestation during a sono exam?

Answer 9

• Forehead
• Orbits
• Nose
• Lips
• Ears

Question 10

What planes are useful for evaluating normal and abnormal anatomy in a sono exam?

Answer 10

• Sagittal
• Transverse
• Coronal

Question 11

What is the primary palate?

Answer 11

Formed as the prominences fuse and becomes the premaxillary portion of the maxilla which holds the incisors

Question 12

What is the secondary palate?

Answer 12

Forms the hard and soft plates. Grow horizontally to form the roof of the oral cavity

Question 13

What is formed by the merging of the nasal prominences?

Answer 13

Philtrum

Question 14

What marks the completion of full facial development?

Answer 14

Palate development is complete by the end of the first trimester

Question 15

What is the difference between the soft and hard palate?

Answer 15

The soft palate is at the back while the hard palate is the bony part closer to the teeth. Functions of soft palate include aiding speech, swallowing, and breathing.

The soft palate and hard palate form the roof of the mouth.

Question 16

What does the term facial cleft refer to?

Answer 16

A wide spectrum of clefting defects usually involving the upper lip, the palate, or both

Question 17

What are the prevalence statistics for facial clefts?

Answer 17

• 1 in 700 births
• 50% both lip and palate affected
• 25% only lip affected
• 25% only palate affected
• Unilateral in 75% of cases
• Craniofacial anomalies have constituted approximately 1/3 of all congenital defects

Question 18

What are the anterior cleft palate anomalies?

Answer 18

• Upper lip with premaxillary cleft
• Complete unilateral cleft lip
• Complete bilateral cleft lip

Question 19

What are the posterior cleft palate anomalies?

Answer 19

• Simple cleft palate
• Unilateral cleft lip and palate
• Complete (bilateral) cleft palate extending to the incisive fossa

Question 20

How are normal orbits characterized in imaging?

Answer 20

Reasonable size and equal distance

• Binocular distance is always measured outer canthi of the eyes.
• Interorbital distance is measurement between the orbits.

Question 21

What is microphthalmia?

Answer 21

Decreased size of the eyeball

Microphthalmia / anophthalmia, which is either unilateral or bilateral, is usually associated with one of about 25 genetic syndromes

Question 22

What is anophthalmia?

Answer 22

Absence of the eye, including optic nerves, chiasma, and tracts

Microphthalmia / anophthalmia, which is either unilateral or bilateral, is usually associated with one of about 25 genetic syndromes

Question 23

What is hypotelorism?

Answer 23

Decreased interorbital distance, often associated with severe anomalies

Question 24

What is holoprosencephaly?

Answer 24

Abnormality of brain development where the brain doesn’t properly divide into hemispheres

Question 25

What defines hypertelorism?

Answer 25

Orbits placed far apart with inter- and biocular distance at or above the 95th percentile

Question 26

What is cyclopia?

Answer 26

*** Single palpebral fissure & single midline orbit** * Rare congenital abnormality * Severe embryologic defect *Commonly associated with:* * Alobar holoprosencephaly * **Proboscis** (soft tissue appendage projecting from just below the forehead) * Median facial clefting * Trisomy 13, Meckel-Gruber, CHARGE Caused by genetic or environmental factors

Question 27

What is micrognathia?

Answer 27

Mandibular hypoplasia causing a receding chin * prevalence: about 1 in 1,000 births * Associated with **methotrexate** a teratogenic drug * Diagnosed: receding chin and short mandible in mid-sagittal facial view

Question 28

Which syndromes are commonly associated with micrognathia?

Answer 28

Treacher-Collins, Robin, and Robert syndromes.

Question 29

Which chromosomal abnormalities are linked to micrognathia?

Answer 29

Trisomy 18 and triploidy

Question 30

What is otocephaly?

Answer 30

A rare, lethal condition with severe mandibular hypoplasia and midline defects like holoprosencephaly and cyclopia

Question 31

What complication is associated with severe micrognathia and why?

Answer 31

Polyhydramnios, due to glossoptosis preventing fetal swallowing.

Question 32

What characterizes macroglossia?

Answer 32

Abnormally large tongue extending beyond the lips; tongue remains out regardless of fetal swallowing * **US findings:** tongue persistently or repeatedly protrudes beyond fetal lips * **Complication:** Polyhydramnios due to impaired swallowing ***Associated disorders:*** * Beckwith-Wiedemann syndrome * Acromegaly * Primary amyloidosis * Congenital hypothyroidism * Down syndrome * Apert syndrome

Question 33

What are the two types of neck cysts?

Answer 33

* **Branchial Cleft cysts:** occur laterally between the sternocleidomastoid muscle and pharynx * **Thyroglossal Duct cysts:** located midline around the hyoid bone

Question 34

What are neck teratomas?

Answer 34

Encapsulated tumors containing tissue from all three embryonic germ cell layers * **Appearance:** Complex cystic/solid tumor * **May contain:** Calcifications * **Possible finding:** Polyhydramnios ***Type matters:*** * **Immature** = more suspicious * **Mature** = likely benign

Question 35

What is epignathus teratoma?

Answer 35

Rare tumor arising from the oral cavity or pharynx, can cause airway obstruction * Can fill oral/nasal cavity and invade intracranial space * May contain complex components (like other teratomas) * Risk of **airway obstruction** → postnatal asphyxia * **Ultrasound:** Complex mass from fetal mouth/neck * **Polyhydramnios** may be present

Question 36

What is cystic hygroma?

Answer 36

Benign lymphatic anomaly characterized by cystic areas within the neck's soft tissues * **Associated with:** Chromosomal abnormalities * **Ultrasound:** Cystic mass near chest wall or behind fetal head/neck * May also see **ascites, edema, placentomegaly**