Hi everyone,
I love this week's topic because it is such an interesting one and is a great way to learn more about and simultaneously lock in any abnormalities we may encounter while scanning OB.
While checking that baby's major bones such as femur, humerus, ribs, spine, and cranium are normal length, density and shape, we must remember to spend some time on hands and feet, to make sure the little piggies are formed and growing properly!
Normal fetal hands should show all 5 digits growing properly and of different lengths (the way normal fingers are), and just the simple motion seen of baby clenching and unclenching their fists can rule out so many abnormalities already.
One abnormality that I feel can be easily overlooked is "trident hands." Trident hand is a malformation of the hand that can be seen in utero, demarcated by short, stubby appearing fingers of even length, and a larger separation of the third and ring finger. This abnormality is typically related to achondroplasia, which would include a whole host of other possible skeletal dysplasias, and so if you were to see this as a possible diagnosis it would be good to double check all other measurements.
Just to really quickly go over achondroplasia-- it is a mutation in the FGFR3 (fibroblast growth factor gene 3) that causes abnormal cartilage formation, affecting the ossification of some bones. It is the most common cause of short limbed, or rhizomelic, dwarfism. Some other abnormalities we may see with this congenital disorder would include shortened and bowed femurs, frontal bossing, flattened nasal bridge, anterior flaring of ribs, and increased uptick in angle from lumbar spine to sacrum.
Here's a great article for more info:
https://radiopaedia.org/articles/achondroplasia?lang=us
