Anat. Also 7 sphyncter. [a. L. sphincter, ad. Gr. σφιγκτήρ band, contractile muscle, f. σφίγγειν to bind tight. So F. sphincter, It. sfintere, Sp. and Pg. esfinter.]
1. A contractile muscular ring by which an orifice of the body (in man or animals) is normally kept closed.
Sometimes with Latin genitive of the part, as Sphincter ani, vaginæ, vesicæ.
1578. Banister, Hist. Man, VII. 97. Some [Arteries] together with certaine Ueynes of Vena caua, do flowe to the Muscles called the Sphincter.
1594. T. B., La Primaud. Fr. Acad., II. 352. This straight gutte hath this muscle, which the physicions call sphincter.
1623. Hart, Arraignm. Ur., II. 4. The two muscles called Sphyncters.
1691. Phil. Trans., XVII. 819. The Fibres that compose the Sphincter of the Bladder.
1740–1. Berkeley, in Fraser, Life (1871), viii. 263. I have also known tow, dipped in brandy and thrust into the fundament, to be effectual in strengthening that sphincter.
1759. Goldsm., Bee, No. 4, ¶ 26. A glutinous liquid, which … it spins into thread, coarser or finer as it chooses to contract or dilate its sphincter.
1807. Med. Jrnl., XVII. 421. In the lower part [of the pupil], the divided fibres of the sphincter receded.
1851. G. F. Richardson, Geol. (1855), 245. A lung … which opens and shuts, at the will of the animal, by the action of a muscular sphincter.
1872. Huxley, Physiol., VI. 145. The muscular fibres are so disposed as to form a sort of sphincter around the aperture of communication.
b. transf. and fig.
1737. M. Green, Spleen, 697. Debarr’d the pleasure to impart By av’rice, sphincter of the heart.
1752. Phil. Trans., XLVII. 455. The animal [i.e., a coral-insect], when it wanted to come forth from its niche, forced the sphincter at its entrance.
1837. P. Keith, Bot. Lex., 335. Their edge has the appearance of being a sort of thickened sphincter capable of opening and shutting.
2. a. attrib., as sphincter-fibre, -power; also sphincter-muscle, = sense 1.
1615. Crooke, Body of Man, 422. Euen the muscles haue a motion which we call Tonicum motum,… especially the two sphincter muscles.
1676. Phil. Trans., XI. 603. His sence was … that they might be rather numerous, though small, Sphincter-muscles.
1774. Goldsm., Nat. Hist. (1824), III. 15. A bony partition, which is closed by a sphincter muscle on the inside.
1808. Barclay, Muscular Motions, 463. Sphincter muscles cannot open themselves.
1876. Curling, Dis. Rectum, 169. A large part of the sphincter muscle may be excised without seriously weakening the retentive power of the anus.
1879. St. George’s Hosp. Rep., IX. 348. The margin of this opening possessed slight sphincter power.
1897. Allbutt’s Syst. Med., III. 365. A spasm of the sphincter fibres at the lower end of the circular coat of the œsophagus.
b. Comb., as sphincter-contracting, -inhibitory, -like adjs.
1841. Penny Cycl., XXI. 160/1. The closing appears to be effected by sphincter-like muscles acting upon valvules.
1899. Allbutt’s Syst. Med., VI. 775. A sphincter-contracting centre, closely associated with a sphincter-inhibitory centre.
Hence Sphincteric a., of or pertaining to, of the nature of, a sphincter. Also Sphinctrate a.
Recent Dicts. give sphi·ncteral and sphincte·rial.
1883. J. M. Duncan, Clin. Lect. Dis. Women (ed. 2), viii. 54. This is a sphincteric opening, and during the child-bearing period of life it must open and close.
1884. C. B. Kelsey, Dis. Rectum, etc. v. 106. No amount of sphincteric contraction could close it.
1887. Sollas, in Encycl. Brit., XXII. 415. Which communicates through a sphinctrate aperture.
