Fetal clenched hands are an antenatal ultrasound observation where the fetal hands are in a constant (permanently) clenched position as if being unable to extend.
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Epidemiology
Associations
Several syndromic conditions are associated with this observation including:
-
aneuploidic
Edwards syndrome (trisomy 18): strong association 2
-
non-aneuploidic
Notably, there is no association with Down syndrome (trisomy 21).
Pathology
Some authors 3 suggest that the abnormal posture results in part from:
muscle variations along the radial margin of the forearm and hand
the absence of thenar muscles, anomalous tendons and attachments among the forearm groups
fusion among the arm flexor group
Radiographic features
Ultrasound
Real-time images are best for assessment where the fetal hands can be directly observed in a persistent clenched position. Often there may also be overlapping fetal fingers (particularly the 2nd finger overlapping the 3rd). Its presence in an antenatal ultrasound scan is sometimes classified as a soft sign for aneuploidic anomalies.
Differential diagnosis
On antenatal imaging consider:
fetal akinesia-hypokinesia syndromes: hand in a temporarily clenched position