Most common type of appendix position is -

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.* Gerlach's 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.