Subjective: Increased thumb width without increased dorso-ventral dimensionComments:
There is substantial variability in thumb width and it may be difficult to determine the threshold for this finding. As it is commonly bilateral, comparing to the contralateral digit will not be helpful. Some have suggested using a definition of thumb width measured at the IP joint of >1.5X the width of the index finger measured at the DIPJ, but no data to support this are available. Note that this term should not be used for thumbs that meet the definition for Macrodactyly. There is a standard for thumb width at birth of 9.8 ± 0.5 mm (1 SD) (see Saul et al. , p 45), but this is not widely used and does not take into account gestational age, or a body who is small for gestational age. The assessment is difficult when the thumb is short.