回盲部付近で小腸が混み合って回腸末端を指摘できないが，盲腸（C）は図１６で盲端になる．図１４の1から始まり，盲腸（C）と上行結腸（A）の背側を上行し，図３の12で盲端になるのは虫垂である．1cm程度に腫大し，壁は良好な造影効果を示し，周囲脂肪組織の濃度上昇または腹膜の肥厚（▲）を認め急性虫垂炎である．手術および病理所見：phlegmonous appendicitis．

参考症例（急性虫垂炎）：43歳女性．7時間前に発症し，次第に増強する上腹部痛と発熱のため来院した．体温：37.7℃，上腹部と臍右側に圧痛，反跳痛と軽度の筋性防御がある．
盲腸（C）は図１０までで，回腸末端（ＴＩ）は図６から始まる．図８と図９の白矢印は石灰化したリンパ節か，憩室内糞石であろう．図９の１が虫垂根部で，図８の２で虫垂結石が嵌頓し，図７の３〜図４の６は1cm程度に腫大した虫垂であり，壁は良好に造影され，周囲脂肪組織の濃度上昇（図２〜図７：▲）を伴い，急性虫垂炎である．A：上行結腸．手術および病理所見：acute on chronic appendicitis．

文献考察：正常虫垂のCT所見．虫垂を認識できない例は男性：13％，女性：24%．正常虫垂の最大径は内容物が多いと10mm大を示すこともあり，42％が6mm以上であった．虫垂炎の診断には虫垂の大きさだけでなく他の二次的所見を参考にして慎重を期すべきである．虫垂の位置は（図）．
Eur Radiol. 2005 Oct;15(10):2096-103.
CT appearance of the normal appendix in adults.
Tamburrini S, Brunetti A, Brown M, Sirlin CB, Casola G.

The aims of this study were to identify (1) the normal range of the appendix on computed tomography (CT), (2) the correlation of patient age and sex with the visibility and appearance of the appendix on CT, and (3) the normal variations in wall thickness, intraluminal content, and location of the appendix. Three hundred seventy-two outpatients underwent abdominopelvic CT. The scans were reviewed on the picture archiving and communication system and appendiceal outer-to-outer wall diameter, wall thickness, location, content and its correlation with appendix diameter were analyzed. The appendix was visualized in 305/372 patients. Its location relative to the cecum was highly variable. The diameter range was 3-10 mm; in 42% of cases the diameter was greater than 6 mm. When the intraluminal content (185/305) was visualized, the diameter was slightly superior to the mean (p=0.0156). In 329 CT scans in which oral contrast material was given, the appendix was filled by contrast material in 74/329 patients. The appendix wall thickness was measurable in 22/305 patients (average 0.15 cm). There is significant overlap between the normal and abnormal CT appearance of the appendix. Consequently the diagnosis of acute appendicitis should be based not only on the appearance of the appendix but also on the presence of secondary signs.PMID: 15912331