| body righting reflexes | Reflex effects upon the neck muscles which bring the head into the correct position in space caused by stimulation of pressoreceptors in the body wall by contact with the ground. (05 Mar 2000) |
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| righting reflexes | Reflex's which through various receptors, in labyrinth, eyes, muscles, or skin, tend to bring an animal's body into its normal position in space and which resist any force acting to put it into a false position, e.g., on its back. See: body righting reflexes, labyrinthine righting reflexes, neck reflexes, optical righting reflexes. Synonym: static reflexes. (05 Mar 2000) |
| optical righting reflexes | Visual stimuli that enable an animal to maintain the correct position of the head in space, by bringing about movements of the muscles of the neck and limbs. (05 Mar 2000) |
| labyrinthine righting reflexes | Stimulation of the proprioceptors of the labyrinth causes changes in tone of the neck muscles which bring the head into its natural position in space. (05 Mar 2000) |
| Lombard voice-reflex test | The observation of fluctuations in the intensity of a patient's voice when a masking noise is increased or decreased; a test useful in assessing functional hearing loss. (05 Mar 2000) |
| abdominocardiac reflex | Mechanical stimulation (usually distention) of abdominal viscera causing changes (usually a slowing) in the heart rate or the occurrence of extrasystoles. (05 Mar 2000) |
| Abrams' heart reflex | A contraction of the myocardium when the skin of the precordial region is irritated. (05 Mar 2000) |
| accommodation reflex | Increased convexity of the lens, due to contraction of the ciliary muscle and relaxation of the suspensory ligament, to maintain a distinct retinal image. (05 Mar 2000) |
| Achilles reflex | A contraction of the calf muscles when the tendo calcaneus is sharply struck. Synonym: ankle jerk, ankle reflex, tendo Achillis reflex, triceps surae reflex. (05 Mar 2000) |
| acousticopalpebral reflex | A form of the wink reflex in which there is a contraction, sometimes very slight, of the orbicularis palpebrarum muscle when a sudden noise is made close to the ear; it is absent in labyrinthine disease with total deafness. Synonym: acousticopalpebral reflex, auropalpebral reflex, cochleo-orbicular reflex, startle reflex. (05 Mar 2000) |
| acquired reflex | A reflex that is gradually developed by training and association through the frequent repetition of a definite stimulus. See: conditioning. Synonym: acquired reflex, behaviour reflex, trained reflex. (05 Mar 2000) |
| acromial reflex | Contraction of the biceps muscle caused by a tap on the acromion or the coracoid process. (05 Mar 2000) |
| acute reflex bone atrophy | Atrophy of bones, commonly of the carpal or tarsal bones, following a slight injury such as a sprain. See: causalgia, reflex sympathetic dystrophy. Synonym: acute reflex bone atrophy, posttraumatic osteoporosis, Sudeck's syndrome. Origin: L. English sweat (05 Mar 2000) |
| adductor reflex | Contraction of the adductors of the thigh caused by tapping the tendon of the adductor magnus muscle while the thigh is abducted. (05 Mar 2000) |
| anal reflex | Contraction of the internal sphincter gripping the finger passed into the rectum. (05 Mar 2000) |