ring

ring

1. A circular band surrounding a wide central opening; a ring-shaped or circular structure surrounding an opening or level area. 2. In anatomy, annulus; sometimes anulus when used as an official alternate Nomina Anatomica term. 3. The closed (i.e., endless) chain of atoms in a cyclic compound; commonly used for "cyclic" or "cycle". 4. A marginal growth on the upper surface of a broth culture of bacteria, adhering to the sides of the test tube in the form of a circle.annulus [NA], anulus [NA]; [A.S. hring]
abdominal r. deep inguinal r
amnion r. the r. formed by the attachment of the amnion to the umbilical cord at its point of emergence from the umbilicus.
annuloplasty r. the dilated annulus is sutured, often to a prosthetic r., thereby reducing it to its normal systolic size.
anterior limiting r. the periphery of the cornea marking the termination of Descemet's membrane and the anterior border of the trabecular meshwork; an important landmark in gonioscopy.Schwalbe's r;
Balbani r. an extremely large puff at a band of a polytene chromosome.
Bandl's r. pathologic retraction r
benzene r. the closed-chain arrangement of the carbon and hydrogen atoms in the benzene molecule. See also cyclic compound.
Bickel's r. lymphoid r
Cannon's r. Cannon's point
cardiac lymphatic r. lymphatic r. of cardiac part of stomach
casting r. refractory flask
choroidal r. a lightly pigmented crescent or r. adjacent to the optic disk.
ciliary r. orbiculus ciliaris
common tendinous r. a fibrous ring that surrounds the optic canal and the medial part of the superior orbital fissure; it gives origin to the four rectus muscles of the eye and is partially fused with the sheath of the optic nerve.annulus tendineus communis [NA], Zinn's ligament, Zinn's r., Zinn's tendon;
conjunctival r. a narrow ring at the junction of the periphery of the cornea with the conjunctiva.annulus conjunctivae [NA];
constriction r. 1. true spastic stricture of the uterine cavity resulting when a zone of muscle goes into local tetanic contraction and forms a tight constriction about some part of the fetus; 2. amniotic bands, under band
crural r. femoral r
deep inguinal r. the opening in the transversalis fascia through which the ductus deferens (or round ligament in the female) and gonadal vessels enter the inguinal canal. Located midway between anterior superior iliac spine and pubic tubercle, it is bounded medially by the lateral umbilical ligament (inferior epigastric vessels) and inferiorly by the inguinal ligament. Indirect inguinal hernias exit the abdominal cavity via the deep inguinal r.annulus inguinalis profundus [NA], abdominal r., annulus abdominalis, internal inguinal r;
Donders' r.'s an obsolete term for the iridescent r.'s or haloes observed by a cloudy cornea due to acute glaucoma.
external inguinal r. superficial inguinal r
femoral r. the superior opening of the femoral canal, bounded anteriorly by the inguinal ligament, posteriorly by the pectineus muscle, medially by the lacunar ligament, and laterally by the femoral vein. Passageway by which many lymphatics from lower limb pass to abdomen. Accommodates enlargement of femoral vein in Valsalva maneuver. Often occupied by a lymph node (Cloquet's) and is the site of femoral hernias.annulus femoralis [NA], crural r;
fibrocartilaginous r. of tympanic membrane the thickened portion of the circumference of the tympanic membrane that is fixed in the tympanic sulcus.annulus fibrocartilagineus membranae tympani [NA], Gerlach's annular tendon;
fibrous r. 1. fibrous r. of heart 2. annulus fibrosus of intervertebral disc
fibrous r. of heart one of four fibrous r.'s that surround atrioventricular and arterial orifices of the heart, providing attachment for the valve leaflets and maintaining patency of the orifice. As part of the fibrous skeleton of the heart, the fibrous r.'s also provide origin and insertion for the myocardium.annulus fibrosus cordis [NA], annulus fibrosus (1) [NA], coronary tendon, fibrous r. (1), Lower's r;
fibrous r. of intervertebral disc annulus fibrosus of intervertebral disc
Fleischer's r. an incomplete ring often present at the base of the keratoconus cone; it may be yellow or greenish from deposition of hemosiderin.
Fleischer-Strumpell r. Kayser-Fleischer r
Flieringa's r. a stainless steel r. sutured to the sclera to prevent collapse of the globe in difficult intraocular operations.
glaucomatous r. glaucomatous halo (1) See Donders' r.'s.
Graefenberg r. obsolete term for a silver or silkworm gut r. designed for insertion into the uterine cavity as a means of contraception.
greater r. of iris the outer, broader of the two zones of the iris.annulus iridis major;
Imlach's r. that part of the inguinal canal which lodges the round ligament of the uterus.
internal inguinal r. deep inguinal r
r. of iris either of two zones on the anterior surface of the iris, separated by a circular line concentric with the pupillary border.annulus iridis;
Kayser-Fleischer r. a greenish yellow pigmented r. encircling the cornea just within the corneoscleral margin, seen in hepatolenticular degeneration, due to copper deposited in Descemet's membrane.Fleischer-Strumpell r;
lesser r. of iris the narrow inner zone of the iris.annulus iridis minor;
Liesegang r.'s colored r.'s of precipitated silver chromate formed when a drop of concentrated silver nitrate is added to the surface of a gel (such as gelatin, agar, or silica gel) containing potassium dichromate.
Lower's r. fibrous r. of heart
lymphatic r. of cardiac part of stomach a group of lymph nodes surrounding the cardia of the stomach.annulus lymphaticus cardiae [NA], cardiac lymphatic r;
lymphoid r. the broken r. of lymphoid tissue, formed of the lingual, faucial, and pharyngeal tonsils.Bickel's r., tonsillar r., Waldeyer's throat r;
neonatal r. neonatal line
pathologic retraction r. a constriction located at the junction of the thinned lower uterine segment with the thick retracted upper uterine segment, resulting from obstructed labor; this is one of the classic signs of threatened rupture of the uterus.Bandl's r., Baudelocque's uterine circle, Scanzoni's second os;
physiologic retraction r. a ridge on the inner uterine surface at the boundary line between the upper and lower uterine segment that occurs in the course of normal labor.
polar r. a thickened, electron-dense ring at the anterior end of certain stages of the Apicomplexa; part of the apical complex characteristic of these sporozoans.
Schatzki's r. a contraction r. or incomplete mucosal diaphragm in the lower third of the esophagus which is occasionally symptomatic.
Schwalbe's r. anterior limiting r
scleral r. the appearance of the sclera adjacent to the optic disk when the retinal pigment epithelium does not extend to the optic nerve.
signet r. the early stage of trophozoite development of the malaria parasite in the red blood cell; the parasite cytoplasm stains blue around its circular margin, and the nucleus stains red in Romanowsky stains, while the central vacuole is clear, giving the ringlike appearance.
r. of Soemmerring a mass of lenticular fibers enclosed between the anterior and posterior portion of the lenticular capsule, leaving the pupillary area relatively free.
subcutaneous r. superficial inguinal r
superficial inguinal r. the slit-like opening in the aponeurosis of the external oblique muscle of the abdominal wall through which the spermatic cord (round ligament in the female) and inguinal hernias emerge from the inguinal canal. See also aponeurosis of external abdominal oblique muscle.annulus inguinalis superficialis [NA], external inguinal r., subcutaneous r;
tonsillar r. lymphoid r
tracheal r. tracheal cartilages, under cartilage
tympanic r. in the fetus, a more or less complete bony ring at the medial end of the cartilaginous external acoustic meatus, to which is attached the tympanic membrane.annulus tympanicus [NA], tympanic bone;
umbilical r. an opening in the linea alba through which pass the umbilical vessels in the fetus; in young embryos it is relatively nearer to the pubis, but gradually ascends to the center of the abdomen; it is closed in the adult, its site being indicated by the umbilicus or navel.annulus umbilicalis [NA], canalis umbilicalis;
vascular r. anomalous arteries (aortic arches) congenitally encircling the trachea and esophagus, at times producing pressure symptoms.
Vieussens' r. limbus fossae ovalis
Vossius' lenticular r. a ring-shaped opacity found on the anterior lens capsule after contusion of the eye, due to pigment and blood.
Waldeyer's throat r. lymphoid r
Zinn's r. common tendinous r

 

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