| auropalpebral 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) |
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| axon reflex | An effect brought about by the passage of the nerve impulses from a sensory ending to the effector organ along divisions of the nerve fibre without traversing a synapse, e.g., as in the vasodilation resulting from stimulation of the skin or the irritation of the conjunctiva; the reaction occurs even when the nerve fibre has been sectioned and thus isolated from the nervous centres. (05 Mar 2000) |
| Babinski reflex | <clinical sign> Extension of the great toe and abduction of the other toes instead of the normal flexion reflex to plantar stimulation, considered indicative of pyramidal tract involvement ("positive" Babinski). Synonym: Babinski reflex, Babinski's phenomenon, great-toe reflex, paradoxical extensor reflex, toe phenomenon. (05 Mar 2000) |
| back of foot reflex | The foot being firmly supported on its inner side, a sharp tap on the dorsal tendons causes extension of the second to the fifth toes. Synonym: back of foot reflex, dorsum of foot reflex. (05 Mar 2000) |
| Bainbridge reflex | An increase in heart rate caused by a rise in pressure of the blood in the right atrium due to increased flow and/or pressure in the great veins at its entrance. (05 Mar 2000) |
| Barkman's reflex | Contraction of the ipsilateral rectus muscle in response to a stimulus applied to the skin below a nipple. (05 Mar 2000) |
| basal joint reflex | Opposition and adduction of the thumb with flexion at its metacarpophalangeal joint and extension at its interphalangeal joint, when firm passive flexion of the third, fourth, or fifth finger is made; the reflex is present normally but is absent in pyramidal lesions. Synonym: finger-thumb reflex, Mayer's reflex. (05 Mar 2000) |
| Bechterew-Mendel reflex | Percussion of the dorsum of the foot causes flexion of the toes; present in a pyramidal lesion. Synonym: dorsum pedis reflex, Mendel-Bechterew reflex. (05 Mar 2000) |
| behaviour 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) |
| Benedek's reflex | <neurology, physiology> Plantar flexion of the foot by tapping the anterior margin of the lower part of the fibula, while the foot is slightly dorsiflexed. (05 Mar 2000) |
| Bezold-Jarisch reflex | A reflex with afferent and efferent pathways in the vagus, originating in unidentified chemoreceptors in the heart and resulting in sinus bradycardia, hypotension, and probable peripheral vasodilation. (05 Mar 2000) |
| biceps femoris reflex | Contraction of the biceps femoris upon tapping its lower part, just above its attachment to the head of the fibula, while the limb is partly flexed at hip and knee. (05 Mar 2000) |
| biceps reflex | Contraction of the biceps muscle when its tendon is struck. (05 Mar 2000) |
| Bing's reflex | When the foot is passively dorsiflexed, plantar flexion occurs if any point on the ankle between the two malleoli is tapped. (05 Mar 2000) |
| bladder reflex | Contraction of the walls of the bladder and relaxation of the trigone and urethral sphincter in response to a rise in pressure within the bladder; the reflex can be voluntarily inhibited and the inhibition readily abolished to control micturition. Synonym: bladder reflex, urinary reflex, vesical reflex. (05 Mar 2000) |