[2]Pietsch, P. Effects of retinoic acid on the muscle patterns produced during forelimb regeneration in larval salamanders (Ambystoma). Cytobios 66: 41-61, 1991.
{Again: the white arrows are the ulno-carpalis muscles.}:
Note: Members of the genus Ambystoma normally have four-fingered hands and lack the counterpart of the human thumb, which in anatomical convention is designated as digit I; the corresponding hand and wrist cartilages, and later bones, bare the numerical designation of the digit; thus carpale II is on the lateral, or radial side of the wrist (or would be if the limb were straightened out like that of a cadaver in the dissecting room). Carpale V is on the limb's ulnar side. Additional details can be found in reference 2.
