| 释义 |
ˈsigmoid, a. and n. Chiefly Anat.
[ad. Gr. σιγµοειδής: see sigma and -oid.]
A. adj.
1. Having the shape of the uncial sigma C; crescent-shaped, semicircular.
Chiefly in sigmoid cavity, sigmoid notch, sigmoid valve.
1670Phil. Trans. V. 2097 We did also observe two Ventricles with the tricuspid or sigmoid-valves. 1741A. Monro Anat. Nerves (ed. 3) 252 A large semicircular or sigmoid Concavity is left. 1798T. Hinderwell Hist. Scarborough ii. i. 213 Nautilites, or Ammonites,..with sigmoid or curved ridges. 1831Knox Cloquet's Anat. 74 The condyle is separated from the coronoid process by the sigmoid notch. Ibid. 206 It is the inner side..of the head of the radius that is received into the small sigmoid cavity of the ulna. 1898Allbutt's Syst. Med. V. 922 Relative insufficiency of the sigmoid valves due to dilatation of the aortic ring.
2. Having a double curve like the letter S.
Esp. sigmoid colon, sigmoid flexure, the last curving portion of the colon before terminating in the rectum.
1786Phil. Trans. LXXVI. 306 The sigmoid flexure of the colon immediately presented itself to view. 1797M. Baillie Morbid Anat. (1807) 174 The gut..is narrower at the sigmoid flexure than at any other part. 1848Proc. Berw. Nat. Club II. 267 The flower stalk is..round,..gracefully bent in a sigmoid flexure. 1873Mivart Elem. Anat. ii. 61 The beautiful sigmoid curvature of the vertebral column. 1896Quain's Elem. Anat. (ed. 10) III. iv. 113 The sigmoid colon may be defined as that part of the colon which is attached to the left iliac fossa from the iliac crest to the brim of the true pelvis. 1962Lancet 5 May 951/2 Anterior resection of the rectum with primary sigmoid-rectal anastomosis for neoplasm of the rectosigmoid region and sigmoid colon.
B. n.
a. The sigmoid flexure of the colon.
1891in Cent. Dict. 1897Allbutt's Syst. Med. III. 967 The sigmoid may be so distended as to reach quite over to the right side of the abdomen.
b. A sigmoid curve (Cent. Dict.).
Hence sigmoiˈdectomy [-ectomy], surgical excision of the sigmoid flexure; sigmoiˈdicity, the extent to which a curve is sigmoid (S-shaped); sigmoiˈditis, inflammation of the sigmoid flexure; ˈsigmoidscope (see quot.); cf sigmoidoscope.
1904Brit. Med. Jrnl. 3 Dec. 1503 By means of the electric sigmoidscope..a clear view of every portion of the inside of the bowel may be obtained, even as high as the top of the sigmoid flexure. 1906P. L. Mummery Sigmoidoscope 55 In the cases of acute proctitis or sigmoiditis an examination with the sigmoidoscope may afford useful information. 1915B. G. A. Moynihan Abdominal Operations (ed. 3) II. 490/1 (Index), Sigmoidectomy. 1938H. E. Bacon Anus, Rectum, Sigmoid Colon xix. 695 (heading) Abdominal resection (sigmoidectomy)—one-stage procedure. 1968A. White et al. Princ. Biochem. (ed. 4) xi. 243 For hemoglobin, a similar plot yields a sigmoidal curve..which obeys the relationship known as the Hill equation y = Kxn/(1 + Kxn) where..the exponent n gives a measure of the sigmoidicity of the curve. 1977Arch. Biochem. & Biophys. CLXXXIV. 300/1 With the enzyme from Am[aranthus] edulis, the response to increasing malate was qualitatively similar to that recorded for the At[riplex] spongiosa enzyme but sigmoidicity was more pronounced. |