The appendix is such a common surgical specimen that one hardly anticipates the possibility of its duplication. However, although it is a very rare anomaly, the so-called double appendix does occur, and it offers a number of interesting points for consideration.
The first question which naturally arises is: What is an appendix, and what are the criteria by which one may identify the organ and separate it from other types of protrusions from the cecum? Cave, in an extensive summary of the knowledge of the comparative anatomy of this region, concluded, contrary to common belief, that a true vermiform appendix identical to that met with in man is found only in gibbons and anthropoid apes, although, peculiarly enough, monotremes and some marsupials possess a strikingly similar structure. Aside from its gross form and position, histologically the appendix is identified and distinguished from the cecum by the amount and arrangement of
WAUGH TR. APPENDIX VERMIFORMIS DUPLEX. Arch Surg. 1941;42(2):311-320. doi:10.1001/archsurg.1941.01210080111006