Is the cecum 12 cm proximal to the splenic flexure?

No, the cecum is not located 12 cm proximal to the splenic flexure. In fact, the cecum is situated at the beginning of the large intestine, while the splenic flexure is located further along, where the colon bends near the spleen. The distance between the cecum and splenic flexure varies among individuals but is generally greater than 12 cm.