| third ventricle | A narrow, vertically oriented, irregularly quadrilateral cavity in the midplane, extending from the lamina terminalis to the rostral opening of the mesencephalic aqueduct. This ventricle communicates at its rostrodorsal corner with each of the two lateral ventricles through the left and right interventricular foramen of Monro. Its narrow roof is formed by the tela choroidea which is attached on either side to the tenia thalami; its lateral wall by the medial surface of the thalamus and, below the hypothalamic sulcus, by the hypothalamus which also forms its floor. In lateral profile, the third ventricle exhibits a number of recesses: in its floor, from before backward, 1) the preoptic recess in the acute angle between the base of the lamina terminalis and the dorsum of the optic chiasm, 2) the infundibular recess extending ventrally into the infundibulum but (in humans) not into the hypophysial stalk, and 3) the mamillary or inframamillary recess caused by the protrusion of the mamillary bodies into the ventricle. From its dorsocaudal corner, the pineal recess extends caudally into the pineal stalk. Synonym: ventriculus tertius, diacele, ventricle of diencephalon. (05 Mar 2000) |
|---|---|
| third ventriculostomy | An operation to establish an opening from the third ventricle to the prechiasmal and interpeduncular cisterns (Stookey-Scarff operation) or from the third ventricle to the interpeduncular cistern (Dandy operation). (05 Mar 2000) |
| anvil sound | In cases of a large pulmonary cavity or of pneumothorax, a clear metallic sound obtained by striking a coin, held against the chest, by another coin, or by flicking the chest wall with one's fingernail; the sound is heard on auscultating the chest wall on the same side anteroposteriorly. Synonym: anvil sound, bell sound, coin test. (05 Mar 2000) |
| atrial sound | The sound produced in late diastole in association with ventricular filling due to atrial systole and related to reduced ventricular compliance. It is a low frequency oscillation that may be normal at older ages owing to a physiologic decline in ventricular compliance but is nearly always abnormal at younger ages if it is of high intensity or palpable. It is common in ventricular hypertrophy, particularly with hypertension, and is almost invariable during acute myocardial infarction. Fourth heart sounds may arise from the right or left ventricle or both. Synonym: atrial sound. (05 Mar 2000) |
| auscultatory sound | A rale, murmur, bruit, fremitus, or other sound heard on auscultation of the chest or abdomen. (05 Mar 2000) |
| bell sound | In cases of a large pulmonary cavity or of pneumothorax, a clear metallic sound obtained by striking a coin, held against the chest, by another coin, or by flicking the chest wall with one's fingernail; the sound is heard on auscultating the chest wall on the same side anteroposteriorly. Synonym: anvil sound, bell sound, coin test. (05 Mar 2000) |
| Campbell sound | A miniature sound with a short round-tipped beak, especially curved for the deep urethra of the young male. (05 Mar 2000) |
| cannon sound | The loud first heart sound heard intermittently in complete atrioventricular block and in interference-dissociation when the ventricles happen to contract shortly after the atria. Synonym: cannon sound. (05 Mar 2000) |
| cardiac sound | The sounds heard over the cardiac region produced by the functioning of the heart. There are four distinct sounds: the first occurs at the beginning of systole and is heard as a "lubb" sound; the second is produced by the closing of the aortic and pulmonary valves and is heard as a "dupp" sound; the third is produced by vibrations of the ventricular walls when suddenly distended by the rush of blood from the atria; and the fourth is produced by atrial contraction and ventricular filling but is rarely audible in the normal heart. The physiological concept of heart sounds is differentiated from the pathological heart murmurs. (12 Dec 1998) |
| gallop sound | The abnormal third or fourth heart sound which, when added to the first and second sound's, produces the triple cadence of gallop rhythm. See: gallop. (05 Mar 2000) |
| van Buren sound | A standard sound, available in several calibers, with a gently curved tip designed to follow the contour of the deep bulbous urethra in the male; used for urethral calibration or dilation. (05 Mar 2000) |
| McCrea sound | A gently curved sound used to dilate the urethra in infants or children. (05 Mar 2000) |
| cavernous voice sound | The hollow or metallic voice sound heard over a pulmonary cavity. (05 Mar 2000) |
| respiratory sound | A murmur, bruit, fremitus, rhonchus, or rale heard on auscultation over the lungs or any part of the respiratory tract. (05 Mar 2000) |
| percussion sound | Any sound elicited on percussing over one of the cavities of the body. (05 Mar 2000) |