Small intestine
It is approximately 1.5 cm in diameter in newborns after 35 weeks of gestational age, and 2.5–3 cm (1 inch) in diameter in adults. On abdominal X-rays, the small intestine is considered to be abnormally dilated when the diameter exceeds 3 cm. On CT scans, a diameter of over 2.5 cm is considered abnormally dilated. The surface area of the human small intestinal mucosa, due to enlargement caused by folds, villi and microvilli, averages 30 square meters.
Large intestine (Chinese medicine)
The large intestine (Chinese: 大肠/大腸: pinyin: "dà cháng") is one of the "fu" organs stipulated by traditional Chinese medicine (TCM). As distinct from the Western medical concept of large intestine, this concept from TCM is more a way of describing a set of interrelated parts than an anatomical organ. It is a functionally defined entity and not equivalent to the anatomical organ of the same name.