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Histologic analysis of fetal ulnar variance
P R Kim1, A A Giachino, H K Uhthoff
1Division of Orthopaedics, University of Ottawa, Ontario, Canada.
The Journal of Hand Surgery
|January 1, 1996
Summary
Fetal wrist development shows a trend from ulna negative to ulna neutral variance. This differs from adult ulnar variance, suggesting growth-related changes in the radius-ulna relationship.
Area of Science:
- Embryology
- Orthopedic Development
- Histology
Background:
- Ulnar variance, the relative length of the ulna and radius, is a known factor in adult wrist conditions.
- The developmental trajectory of ulnar variance during fetal growth is not well-established.
Purpose of the Study:
- To histologically examine fetal wrists to determine the pattern of ulnar variance during early development.
- To compare fetal ulnar variance with established adult populations.
Main Methods:
- Histological examination of 28 fetal wrists.
- Gestation age ranged from 5 to 21 weeks.
- Classification of wrists into ulna negative or ulna neutral based on radius-ulna length.
Main Results:
- A trend from ulna negative to ulna neutral variance was observed with increasing gestational age.
- In early gestation (5-8 weeks), 80% of wrists were ulna negative.
- By late gestation (18-21 weeks), 78% of wrists were ulna neutral.
- Overall, 13 fetuses showed ulna negative variance and the rest showed ulna neutral variance.
Conclusions:
- Fetal ulnar variance differs significantly from adult populations.
- Developmental factors during growth must alter the fetal radius-ulna relationship.
- Further research is needed to identify the specific factors influencing this change.