AGENESIS of the human appendix is a rare anatomic finding. Collins1 found 1 case in 104,066 appendectomies, or an incidence of 0.0009%. He found 60 cases had been reported in the world literature through 1950. Eleven cases have been reported since, and I am adding a 12th.
All carnivora possess some type of cecal appendix, but the human vermiform appendix is found in comparable structure only in high anthropoid apes. No endocrine functions can be attributed to the human appendix.The cecum is derived from the distal branch of the primitive intestinal loop.2 There, at a short distance from the implantation of the vitelline duct, a dilatation appears on the free margin. This appears in the form of a diverticulum and represents the anlage of the cecal apparatus. This is found in the five-week embryo. This diverticulum becomes elongated and gradually assumes the shape of a funnel,
GEORGE H. PESTER. Congenital Absence of the Vermiform Appendix. Arch Surg. 1965;91(3):461–462. doi:10.1001/archsurg.1965.01320150091014