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.
Small intestine (Chinese medicine)
SI Meridian Points (S1-S10):
SI-1 (Shao Ze/Lesser Marsh) : Resuscitates, promotes lactation, opens orifices, clears Heat. 
SI-2 (Qian Gu/Front Valley): Clears Heat, activates the meridian.
SI-3 (Hou Xi/Back Stream): Benefits the neck and back, treats malaria activates the meridian.
SI-4 (Wan Gu/Wrist Bone): Activates and clears the meridian, resolves Damp-Heat.
SI-5 (Yang Gu/Yang Valley): Clears Heat, clears the meridian, reduces swelling.
SI-6 (Yang Lao/Nourishing the Aged): Activates the meridian, benefits the eyes, benefits the shoulder and arm, alleviates pain. 
SI-7 (Zhi Zheng/Branch of the Upright): Activates the meridian, frees obstructions, calms the Shen, clears Heat, alleviates pain. 
SI-8 (Xiao Hai/Small Sea): Activates the meridian, alleviates pain, clears Heat and Damp-Heat.
SI-9 (Jian Zhen/True Shoulder): Activates the meridian, alleviates pain, benefits the shoulder. 
SI-10 (Nao Shu/Upper Arm Shu): Activates the meridian, alleviates pain, benefits the shoulder.https://theory.yinyanghouse.com/acupuncturepoints/smallintestine_meridian_graphic
http://www.sacredlotus.com/go/acupuncture/channel/small_intestine_channel_of_hand_tai_yang
http://www.acatcm.com/small-intestine-meridian-hand-tai-yin-points