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Related to aryepiglottic fold: Laryngeal inlet, laryngeal saccule, Conus elasticus


in geology, bent or deformed arrangement of stratified rocks. These rocks may be of sedimentary or volcanic origin. Although stratified rocks are normally deposited on the earth's surface in horizontal layers (see stratificationstratification
(Lat.,=made in layers), layered structure formed by the deposition of sedimentary rocks. Changes between strata are interpreted as the result of fluctuations in the intensity and persistence of the depositional agent, e.g.
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), they are often found inclined or curved upward or downward. Arches, or upfolds, in stratified rock are called anticlines; depressions or downfolds, synclines. A third type of fold, the monocline, is a steplike structure sloping in one direction only. It is more correctly called a flexure and generally passes at depth into a fracture called a fault. An imaginary line drawn along the crest of an anticline or the trough of a syncline is its axis; the two sides curving away from the axis are the limbs. If both limbs, dipping in opposite directions, make the same angle with the horizontal, and if an imaginary axial plane passed through the axis and the center of the fold is vertical and divides the fold into two equal halves, the fold is symmetrical; if the limbs make unequal angles, and if the axial plane is inclined and does not bisect the fold, the fold is asymmetric. If one limb lies partly under the other, and the axial plane is inclined, the fold is overturned; if one limb lies almost completely under the other, and the axial plane is almost horizontal, the fold is recumbent. The axis of a fold cannot be indefinitely extended parallel to the horizontal, but plunges or emerges as the fold tapers off to a plane. Certain domes are very short anticlines with axes plunging at both ends, while some basins, similarly, are synclinal structures. Folds are commonly formed at some distance below the surface, but complete folds or portions of folds are exposed by erosion. Anticlines frequently have their crests eroded, till only the worn-down stumps of the two limbs remain. In a similar manner synclines may be eroded so that only the edges of the limbs project above the surface. The ridge crests of the Appalachian Mts. are eroded limbs of folds. The nature of the original fold can generally be determined from the arrangement of the outcrops, or exposed portions; thus, two outcrops dipping toward each other mark a syncline, and two outcrops dipping away from each other, an anticline. Folds on a grand scale, extending, for example, most of the length of a continent, are known as geosynclines and geanticlines. The immediate cause of folding is generally conceded to be the horizontal compression of the earth's surface, anticlines being squeezed up by this compression and synclines formed between anticlines. The problem of the ultimate cause of fold formation is similar to that of fault formation, both being earth movements involved in mountainmountain,
high land mass projecting conspicuously above its surroundings and usually of limited width at its summit. Although isolated mountains are not unusual, mountains commonly form ranges, comprising either a single complex ridge or a series of related ridges.
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 building and plate tectonicsplate tectonics,
theory that unifies many of the features and characteristics of continental drift and seafloor spreading into a coherent model and has revolutionized geologists' understanding of continents, ocean basins, mountains, and earth history.
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. Porous and permeable rocks of anticlines often contain oil and gas reservoirs. Organic remains of late Paleozoic tree fern swamps were converted to anthracite coal during the folding of the Appalachian Mts.



(also flexure), a tectonic structure in which a stratum or bed is strongly bent in two opposite directions. A fold consists of five elements, namely, two bends and three limbs. Two of the limbs are outside the bends; the third, or middle, limb connects the bends. Each element is described by its own bedding parameters, and the relationships between the parameters determine the many varieties of folds.

According to the bedding of the limbs, we distinguish among simple, plunging, and cross folds; according to the inclination of the hinges of the bends, folds are classified as vertical, inclined, and nonplunging (Figure 1). The size of a fold ranges from fractions of a meter to many kilometers. The inclination of the limbs ranges from barely discernible to vertical.

Figure 1.

Note on Figure 1. Location of the strata in the major types of folds:, (a) simple fold, (b) plunging fold, (c) cross fold, (d) nonplunging fold, (e) inclined fold, (f) vertical fold; the symbol Fold indicates that the strata are horizontal, the symbol Fold shows the direction in which the strata dip

Folds are found in cratons and folded regions. Especially large folds are found along the margins of cratons and the edges of syneclises. Some folds affect the accumulation of sediment and determine the distribution of the facies and thicknesses of sedimentary strata. Folds are sometimes associated with petroleum deposits.


A plication or doubling, as of various parts of the body such as membranes and other flat surfaces.
A bend in rock strata or other planar structure, usually produced by deformation; folds are recognized where layered rocks have been distorted into wavelike form.


1. a hollow in undulating terrain
2. Geology a bend in stratified rocks that results from movements within the earth's crust and produces such structures as anticlines and synclines
3. Anatomy another word for plica


a church or the members of it


(1) For foldable phones, see Galaxy Fold and iPhone Fold.

(2) An invisible line on a Web page that is at the bottom of the first full page on screen. The fold determines how much is visible at first glance (see above the fold).
References in periodicals archive ?
The commonest symptoms are hoarseness of voice, dyspnea and dysphagia and commonest sites are aryepiglottic folds, arytenoids as seen in our case.
(4) In 1985, Seid et al first described the use of a C[O.sub.2] laser in excision of the aryepiglottic folds. (5) Solomons and Prescott described epiglottopexy and partial epiglottectomy to treat variations in supraglottic anatomy that cause supraglottic collapse.
Computed tomography (CT) with contrast demonstrated a hyperdense mass that extended from the right aryepiglottic fold to the right vocal fold (figure 2).
He was fiberoptically intubated and underwent suspension microlaryngoscopy, which demonstrated a well- circumscribed, encapsulated lesion located in the vallecula and encompassing the right aryepiglottic fold. The tongue-base mass was fully removed via a transoral endoscopic C[O.sub.2] laser resection; because the lesion was so large, the removal was performed in a piecemeal fashion (figure 4).
The otolaryngologist service performed a laryngoscopic examination, which revealed left side erythema and an edematous epiglottis and aryepiglottic folds consistent with acute epiglottitis (Figure 1).
Flexible fiberoptic laryngoscopy demonstrates the desquamating lesions of the subglottic region (arrow) (A) and the posterior cricoid, aryepiglottic folds, and piriform sinuses (arrows) (B).
[2] The common sites of occurrence of the benign lesions of larynx are vocal cords, anterior commissure, false cords, epiglottis, aryepiglottic folds and ventricle in chronological order.
Diffuse laryngeal edema involving the aryepiglottic folds, vocal fold paralysis, and upper airway obstruction are all potential clinical findings in patients with laryngeal manifestations of SLE.
There are many receptors in the mucosa of supraglottis which are highly sensitive to a vibration of laryngeal mucosa; whereas, tactile receptors are found in the epiglottis, aryepiglottic folds and vocal processes [6].
Fibreoptic nasoendoscopy revealed large bilateral supraglottic masses centered on the aryepiglottic folds. The right tumour was significantly larger than the left and encroached on the laryngeal inlet.
In the pharyngeal phase, the larynx prevents material from entering the trachea by closing the true vocal cords, false vocal folds and aryepiglottic folds respectively.
(2) Lesions are found in the interarytenoid areas and on the aryepiglottic folds. Later, the true and false cords may be involved and airway compromise may develop.