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Radiology
Micrognathia and Retrognathia
Built from Obstetric Imaging
What’s inside
9 sections · 78 slides
Overview
- What this deck covers
What these conditions are
Three grades of jaw problem, and the word for each
- Start with the fetal profile
- A jaw in the wrong place
- A jaw that never grew
- The extreme end of the range
- One spectrum, three names
- Receding chin with a normal-sized jaw
- Profile of a markedly small lower jaw
- Coronal view showing no mandible at all
- The same baby after delivery
- 1:1000
Why a jaw fails to grow
Multifactorial growth, genes, drugs and a stiff joint
- What normally builds the mandible
- The cause is still not settled
- Why a small jaw so often means a cleft palate
- Reading that chain
- Genes and the environment
- Drugs and toxins in pregnancy
- A checklist of syndromes is coming
- Abbreviations used in the list
- Associated Clinical Findings in Fetal Micrognathia
- Associated Clinical Findings in Fetal Micrognathia (continued)
- Associated Clinical Findings in Fetal Micrognathia (continued)
- Associated Clinical Findings in Fetal Micrognathia (continued)
- Associated Clinical Findings in Fetal Micrognathia (continued)
What the finding means
Two conditions, two very different outlooks
- The single most useful distinction
- What happened to 54 fetuses called micrognathic
- The lesson from that series
- Syndromes that hit the jaw first
- Pierre Robin sequence
- Bone and muscle disease
- How often the chromosomes are at fault
- The face as the first clue
- What to do the moment you find it
- How deep should the genetic testing go
How to image the fetal jaw
From an eyeballed profile to three hard numbers
- The profile belongs in every anatomy scan
- The jaw is readable surprisingly early
- Eyeballing the profile is only step one
- Confirm it in the cross-sections
- Three measurements do the work
- Drawing the inferior facial angle
- What the angle should measure
- The angle drawn on a real profile
- Measuring the jaw from above
- Turning a diameter into an index
- 100%
- Reading those numbers
- Both jaw diameters on one image
- The mandibular ratio
- Which index answers which question
- Then look for a swallowing problem
- The whole scanning pathway
MRI and three-dimensional ultrasound
When flat grey slices are not enough
- When fetal MRI earns its place
- What three-dimensional scanning adds
- Multiplanar reconstruction of a small jaw
- The rendered face, enlarged
- Turning the volume into a face
- Front view of a small jaw at 22 weeks
- Side view of the same fetus
- Why 3D gets harder later on
Things that only look like a small jaw
Two common false impressions, and the fix
- Two ways a normal chin fools you
Treatment, before and after birth
Fluid, airway and a jaw that can be lengthened
- What can be done before birth
- How a small jaw floods the uterus
- After birth: retrognathia is the easy one
- After birth: micrognathia is not
- The chain that kills
- Picking out the high-risk baby
- Securing the airway at delivery
- Lengthening the jaw itself
- What lengthening achieves
Take it away
What the referring clinician needs from you
- What the referring physician needs to know
- What the referring physician needs to know
- Key points to carry away
- “
- Suggested reading
- References
- References (continued)
- References (continued)
- Obstetric Imaging: Fetal Diagnosis and Care, 2nd Edition