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Embryological development and prevalence of thumb flexion creases
1First Department of Anatomy, Nihon University School of Dentistry, Tokyo, Japan.
The Anatomical Record
|September 1, 1988
Summary
Thumb flexion creases develop early in fetal development alongside volar pads, not from thumb movements. Oblique and extra creases are common, not anomalies.
Area of Science:
- Embryology
- Human Anatomy
- Dermatoglyphics
Background:
- Thumb flexion creases are a feature of human hands.
- Their developmental origins and morphological variations are not fully understood.
Purpose of the Study:
- To investigate the embryological development and morphology of thumb flexion creases.
- To determine the timing and location of crease appearance during fetal development.
- To clarify the classification of oblique and extra creases.
Main Methods:
- Examination of 178 human fetuses (6-20 weeks gestational age).
- Analysis of 225 normal adult hands (19-81 years).
- Observation of crease morphology, timing, and location.
Main Results:
- Most flexion creases (regular, extra, oblique) developed concurrently with fetal volar pads.
- Crease development appeared independent of thumb flexion movements.
- Regular creases seem to form from inward-developing radial and ulnar segments.
- Oblique and extra creases were frequent in both fetuses and adults.
Conclusions:
- Thumb flexion creases originate during early embryogenesis, linked to volar pad formation.
- Oblique and extra creases on the proximal phalanx of the thumb are common variations, not anomalies.
- These findings contribute to understanding normal dermatoglyphic patterns.