Module 11: Fetal Face and Neck Flashcards
When does embryology start and when is it completed?
5 weeks LMP and 10 weeks LMP
What are the 5 main facial processes that move together and fuse?
- 1 nasal frontal process
- 2 maxillary prominences
- 2 mandibular prominences.
How does the nasal frontal process move?
Starts superior and moves inferiorly
What does the nasal frontal process form and what is the key piece?
Mid forehead, nose, central maxilla, anterior palate
Key: Central upper lip
What can sometimes be mistaken for a cleft lip?
The philtrum (cupids bow)
How do the maxillary and mandibular prominences move?
Medially
What do the maxillary prominences form and what it the key piece? (4)
Cheeks, maxilla, hard palate
Key = Lateral aspects of upper lip
What do the mandibular prominences move to form?
Move medially and fuse to form mandible
Where does the nose start and where does it move?
Starts as 2 nasal placodes above orbits that move med/inf
Where do the eyes start and move?
Start laterally and move inwards
Where do the ears start and move?
Start below the mandible and move out and up
Facial anomalies occur at what rate?
1/600 births
What condition occurs in conjunction with 60% of the facial anomalies and how often are non-facial anomalies also present?
Polyhydramnios occurs with 60 % of facial anomalies
50% of the time other non-facial anomalies also occur due to chromosomal abnormalities
What can affect the development of the face? (4)
Drugs such as:
Alcohol, codeine, valium, anti-epileptic drugs
In what view do you obtain binocular distance, orbital size, and presence of the hard palate?
Axial/trans view through the face
In what plane are you assessing the nose/lip?
Tangential coronal (intact upper lip and 2 nostrils seen)
In what plane are you assessing fetus profile?
Midline sagittal
What are limiting factors for our images? (2)
- Oligohydramnios
- High maternal BMI
What is OOD and IOD?
What should the IOD equal?
OOD = Outer Occular Distance (Distance between outer edges of eyes)
IOD = Inner Occular DIstance (Distance between Inner edges)
IOD should be about the distance of one orbital globe (eyeball)
What can be used to date the pregnancy when the BPD cannot be obtained due to a low head and what sgould the orbits be assessed for?
Outer to outer orbital distances
The lens should be seen in orbits to prove the presence of eyeballs
What is anophthalmia?
Congenital absence or severe hypoplasia of the eyes
What is anophthalmia associated with?
Trisomy 13
What is microphthalmia?
Small eyes
How do you measure to ensure you are assessing microphthalmia?
Interocular diameter (between eyes)
What is hyperteliorism?
Widely spread eyes (inner-ocular meas increased)
What is hyperteliorism most commonly due to?
Mass blocking anterior migration (ex: encephalocele)
What is hypoteliorism?
Eyes too closely positioned
What is hypoteliorism associated with?
Trisomy 13
What is cyclopia and what often develops?
Fusion of eyes into one
Nose as supraorbital proboscis develops
What is cyclopia associated with?
Trisomy 13
What is ethmocephaly?
2 closely spaced but separate eyes with a supraorbital proboscis
What is cebocephaly?
2 closely spaced but separate eyes with a centrally placed nose with only one blind ended nostril
What is a proboscis?
Instead of a normal nose, a tuft of tissue develops midline above the eyes
What is a median cleft face and what is another name?
Cleft in the middle of the nose (nasal and maxillary structures fail to fuse)
AKA: Cleft nose
What are the 5 lip anomaly patterns?
- Cleft lip alone
- Unilateral cleft lip and palate
- Bilateral cleft lip and palate
- Midline cleft lip and palate
- Facial defects associated with amniotic band syndrome
Clefting occurs in 40% of fetuses with which trisomy?
Trisomy 18
Clefting occurs in 60% of fetuses with which Trisomy?
Trisomy 13
The isolated cleft palate is more likely associated with what?
Additional anomalies
Why is polyhydramnios and a small stomach often seen with clefting?
Fetal swallowing can be disturbed
What is macroglossia and what is it associated with?
Abnormally large protruding tongue
Associated with T21
What are sonographic appearances of Beckwith-Wiedemann syndrome? (5)
- Macroglossia
- Macrosomia (abnormally large fetus)
- Omphalocele
- Renal hyperplasia or renal dysplasia
- Increased risk of developing a Wilm’s tumor and hepatoblastoma
What is micrognathia?
Abnormally receded chin
What is frontal bossing?
Abnormally bowed forehead
If the ears are places low or small, it can be associated with what?
Trisomy 21, 18, or 13
When does the fetal thyroid start to function?
12 weeks
How does fetal hyperthyroidism or hypothyroidism affect the thyroid and what disease may cause hyperthyroid?
Hyper/hypo-thyroidism both enlarge the fetal thyroid
Maternal Graves disease can cause hyperthyroid
What may you see on U/S with an enlarged fetal thyroid? (6) and how is it treated?
- Neck mass,
- Hyperextension of the neck
- IUGR
- Oligohydramnios
- Tachycardia
- Polyhydramnios if mass is obstructive
Treated in utero with drugs
What is considered to be a nuchal cord and how do you assess?
Cord looped 2 or more times around the neck
Turn sag to count loops
What is a cystic hygroma?
Septated nuchal fluid in the neck that is usually of lymphatic origin
Why does cystic hygroma develop?
Arises due to a failure of the lymph system to communicate with venous system in neck but not ALL cystic hygromas have lymphatic origin
Hygromas are often accompanied by what?
Hydrops and cardiac abnormalities
> 60% of fetuses with cystic hygromas have what?
Chromosomal abnormalities (poor prognosis)
What syndromes is cystic hygroma associated with? (5)
- Turner’s
- Downs
- Noonan
- Fetal alcohol
- Death (postmortem effect)
At what weeks and CRL is nuchal translucency done?
Between 11 and 14 weeks
CRL = 45 - 84 mm
What is a normal nuchal translucency measurement and what is abnormally increased associated with?
< 3 mm (depending on maternal age)
Increased = trisomy’s
What could be mistaken for the nuchal translucency?
Hygroma, amniotic membrane
When is nuchal fold assessed and what view?
Between 16 and 24 weeks
What is nuchal fold thickening due to?
Subcutaneous edema >6mm
What percentage of fetuses with Down’s syndrome have a thick nuchal fold?
42%
Which plane is used to assess the nuchal fold and nuchal translucency?
Nuchal fold = Axial posterior fossa image
Nuchal translucency = perfect midline sag
What landmarks must be on the nuchal fold image?
CSP anteriorly and cerebellum posteriorly
Why do we stop measuring the nuchal fold after 24 weeks?
Larger fetuses naturally have a bigger fold
Teratomas are composed of what tissue?
Endoderm, mesoderm and ectoderm
Teratomas may obstruct swallowing causing what?
Polyhydramnios
What is dystocia?
Difficulty giving birth (often associated with fetal teratomas)
