Embryological development of human palmar, plantar, and digital flexion creases.

The aim of this study is to document the prenatal stages of development of the flexion creases on the surfaces of the human palm, sole, and digits. We used 160 human fetuses, 6-20 weeks of gestational age, to observe the morphological features of the hand and foot, as well as the period and location of the appearance of the flexion creases. We found that most creases develop concurrently with the appearance of the fetal volar pads and the rest develop independently of them. Furthermore, with some exceptions, the creases seem to develop independently of the flexion movements of hand and foot.