| cross-sectional study | <epidemiology> A study in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with longitudinal studies which are followed over a period of time. Synonym: horizontal study. (18 Jul 2002) |
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| cross-table lateral projection | <radiology> Lateral projection radiography of a supine subject using a horizontal X-ray beam. (05 Mar 2000) |
| crossallergy | <immunology> An allergic response to several cross reactive allergens, the fact that a patient allergic to one component will also tend to be allergic to a similar component. (18 Nov 1997) |
| crossbite | <dentistry> A malocclusion where some of your upper teeth are inside of your lower teeth when you bite down. (08 Jan 1998) |
| crossbite teeth | Posterior teeth designed to permit the modified cusps of the upper teeth to be positioned in the fossae of the lower teeth. (05 Mar 2000) |
| crossbreed | Synonym: hybrid. 2. To breed a hybrid. (05 Mar 2000) |
| crossbreeding | hybridisation |
| crossed adductor jerk | Contraction of the adductors of the thigh and inward rotation of the limb elicited by tapping the sole. Synonym: crossed adductor jerk. (05 Mar 2000) |
| crossed adductor reflex | Contraction of the adductors of the thigh and inward rotation of the limb elicited by tapping the sole. Synonym: crossed adductor jerk. (05 Mar 2000) |
| crossed anaesthesia | Anaesthesia of one side of the head and the other side of the body due to a brainstem lesion. (05 Mar 2000) |
| crossed aphasia | Aphasia in a right-handed person due to a solely right cerebral lesion. (05 Mar 2000) |
| crossed cylinders | A lens used in refraction to determine the strength and axis of a cylindrical lens to correct astigmatism; a combination of concave and convex cylinders of like power whose axes are at right angles to each other. (05 Mar 2000) |
| crossed embolism | Passage of a clot (thrombus) from a vein to an artery. When clots in veins break off (embolise) , they travel first to the right side of the heart and, normally, then to the lungs where they lodge. The lungs act as a filter to prevent the clots from entering the arterial circulation. However, when there is a hole in the wall between the two upper chambers of the heart (an atrial septal defect), a clot can crossparadoxically from the right to the left side of the heart, then pass into the arteries. Once in the arterial circulation, a clot can travel to the brain, block a vessel there, and cause a stroke (cerebrovascular accident). Because of the risk of stroke from crossed embolism, it is usually recommended that even small atrial septal defects be closed (repaired). Also called: paradoxical embolism. (12 Dec 1998) |
| crossed extension reflex | Extension of the contralateral hind limb when the paw of an animal is painfully stimulated or the central cut end of an afferent nerve, e.g., the peroneal, is stimulated; sometimes occurs in humans upon tapping the skin. (05 Mar 2000) |
| crossed eyes | <clinical sign> A deviation of the eye which the patient cannot overcome. The visual axes assume a position relative to each other different from that required by the physiological conditions. The various forms of strabismus are spoken of as tropias, their direction being indicated by the appropriate prefix, as cyclo tropia, esotropia, exotropia, hypertropia and hypotropia. Also called cast, heterotropia, manifest deviation and squint. Origin: Gr. Strabismos = a squinting (18 Nov 1997) |