Ilium vs ileum
The medical terms ileum and ilium have been causing great confusion to medical students and junior doctors alike for decades now. Only separated by one letter, the second vowel, the pronunciation may be identical, or differ slightly with the i sound resembling that in "bit" for ilium (ɪlɪəm) or be slightly longer (actually more "close", in phonetic terms) as in "beet" for ileum (ɪliəm).
Of course, the ileum (adjective: ileal) refers to the distal portion of the small bowel. Terms relating to the ileum include the ileocecal valve and ileocolic vessels.
History and etymology
Although both "ileum" and "ilium" are suggested to be ultimately derived from Latin "ile", meaning intestines, "ilium" may also have its origin in Latin "ilium" which denotes the "lower abdomen" or "flank".