The regeneration of double dorsal and double ventral limbs in the axolotl.

Abstract

Surgically made double dorsal and double ventral upper arms, comprising double extensor and double flexor muscles respectively, were amputated immediately following operation; both limb types regenerated. In terms of skeletal anatomy, a range of limb types was found. These included four-digit limbs of normal cartilage pattern, and hypomorphic limbs having from one to three digits. All of the double dorsal and the majority of the double ventral limbs were symmetrical in the dorsal-ventral axis. This was detected by analysing their muscle patterns at carpal and mid-forearm level, and muscle and epidermal characteristics in the metacarpal region are discussed in terms of the significance of healing time and stump pattern on the regenerative ability of surgically created limb regions.