<prompt> Most common type of appendix position is -RetrocaecalPelvicPost ilealParacaecal  <response>: Ans. is a i.e., Retrocaecal Vermiform appendix It is a narrow worm-like tubular diverticulum which arises from the postero-medial wall of the caecum about 2 cm below ileocaecal function and is suspended by a peritoneal fold known as mesoappendix or appendicular mesentery. Length of appendix is 2-20 cm average 9 cm. The appendix lies in the right iliac fossa. Base of the appendix is fixed, but the tip can point in any direction, according to which positions of appendix are classified:-i Retrocaecal 12 O clock positon : It is the commonest position in 65 of individuals.ii Pelvic 4 O clock position : It is second commonest position in 30 of individuals.iii Paracolic 11 O clock position : In 20 of subjects.iv Midinguinal or subcaecal 6 O clock position : In 2 of subjects.v Pre and post-ileal 3 O clock position : In 1 and 0.4 subjects, respectively.vi Promontoric 3 O clock position : In 1 of subjects. Gerlachs valve valvula processus vermiformis is a fold of mucous membrane found at opening of vermiform appendix of some people. Appendix develops from midgut and therefore is supplied by superior mesenteric artery through appendicular branch of ileocolic artery. 