semicircular


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semicircular

 [sem″e-ser´ku-lar]
shaped like a half-circle.
semicircular canals the passages in the bony labyrinth of the inner ear that control the sense of equilibrium. Each ear has three semicircular canals (anterior, lateral, and posterior), at approximately right angles to each other, which are filled with fluid and have ampullae (enlarged portions) at one end that contain nerve endings. (See also Plates.)

The semicircular canals respond to movement of the head. When the head changes position in any direction, the fluid in the canal that lies in the plane of movement also moves, but because of its inertia the fluid flow lags behind the head movement. Thus the fluid presses against the delicate hairs of the nerves in the ampulla, and the nerves then register the fact that the head is turning in a given direction so that the body can seek to maintain its equilibrium.

It is the fluid movement in the semicircular canals that causes the feeling of dizziness or vertigo after spinning. When the spinning stops, the fluid in the horizontal canal continues to move for a moment in the direction of the spin, giving a temporary false reading that the head is turning in the other direction. motion sickness is caused by the unusual and erratic motions of the head in an airplane, car, or ship, and the resulting stimulation of the semicircular canals.

sem·i·cir·cu·lar

(sem'ē-sir'kyū-lăr),
Forming a half circle or an incomplete circle.
Synonym(s): semiorbicular

semicircular

(sĕm″ē-sŭr′kū-lăr) [″ + circulus, a ring]
In the form of a half circle.
References in periodicals archive ?
In the control group, there were no significant differences between left and right ears in terms of VOR gains, and the average VOR gains for PSCC, anterior semicircular canal (ASCC), and LSCC were 0.96[+ or -]0.14, 0.96[+ or -]0.13, and 0.99[+ or -]0.09, respectively, for a total of 40 ears.
The semicircular canal bone rim was examined with images in the parallel (Poschl), perpendicular (Stenver), and oblique sagittal planes to SSC.
Each of the semicircular canals is positioned at a different angle and is especially sensitive to different movements: up and down, side-to-side, and tilting from one side to the other.
(4) The hearing loss may be the result of an injury to the posterior semicircular canal during the surgeon's attempt to expose the internal acoustic canal (IAC) posteriorly.
In this study, we used the guinea pig as an experimental model, and we created dehiscence in the superior semicircular canal to simulate SSCD using a surgical technique.
According to the Jongkee's formula, semicircular canal paralysis (Cp) and directional preponderance (Dp) were calculated.
In this report, we have demonstrated three patients with radiologically and surgically confirmed horizontal semicircular canal fistula but with a false negative fistula test.
Um estudo microscopico com a finalidade de determinar a prevalencia da DCSS na populacao geral, analisou 1000 ossos temporais obtidos atraves de autopsias, e encontrou que a deiscencia do canal semicircular superior ocorreu em aproximadamente 0,7% dos individuos estudados, reafirmando a baixa incidencia da doenca.
We realized that such weighted-semicircular elements naturally generate corresponding semicircular elements.
French doors lead to a stone-balustraded, semicircular terrace with panoramic ocean and mountain views.
Section 4 discusses a feeding circuit for impedance matching of a semicircular patch and one design is fabricated and measured.
The hearth was built as a semicircular niche in the north end of the Rotunda's Lower East Oval Room.