Reflex

(ref-fleks)[re, back; flectere, to bend]. I. Anything reflected or thrown back. 2. A reflex act. R. Act, an act following immediately upon a stimulus without the intervention of the will. R. Arc, the mechanism nece ary for a R. action; it consists of an afferent or sensory nerve; a nerve-center to change this sensory impulse into a motor one; and an efferent or motor nerve to carry a motor impulse to the muscle or group of muscles. OF REFLEXES. Effect Produced. Significance. Contraction of muscles about Shows integrity of spinal umbilicus. cord from eighth to twelfth dorsal nerve. Clonic contractions of ten do A chillis, dependent upon alternate contraction and relaxation of anterior tibial and calf-muscles. Contraction of biceps muscle. Normal; increased by causes increasing kneejerk. Pupillary dilatation. Retraction of testicle on same side. Shows integrity of cord between the first and second pairs of lumbar nerves. TABLE OF REFLEXES.— Continued. Name. How Obtained. Effect Produced. Cro ed. Stimulation of one side Reflex on opposite side of of body. bodv. Deep. Reflexes developed by percu ion of tendons or bones. Dorsal. Same as Erector spina. Epigastric. Stimulation of skin in Dimpling in the epigastrium, fifth or sixth inter cos due to contraction of the tal space near axilla. highest fibers of the rectus abdominis muscle. Erector spinae. Stimulation of skin Local contraction of th along border of erector muscles. spinae muscle. Evelid-closure. Irritation of conjunctiva. Closure of lid. Femoral. Irritation of s k i n on Plantar flexion of first three upper anterior aspect toes and of the foot, and exof thigh. tension of the knee-joint. Front-tap. See Tendo A chillis. Gluteal. Firm sudden stroking of Contraction of glutei. skin over buttock. Interscapular. See Scapular. Iris-contraction. See Pupillary. Downward stroke with Clonic movements of inferior Jaw-jerk, clonus. or jaw a hammer on the lower maxilla. jaw hanging pa ively or gently supported by the hand. Knee-jerk. By striking patellar ten- Contraction of quadriceps don after rendering it muscle, the foot being jerked tense by flexing the forward. knee at right angle. Laryngeal. Irritation of fauces Cough. larynx, etc. Lumbar. Same as Erector spina. Nasal. Irritation of Schneide- Sneezing. rian membrane. Obliquus. Irritation of skin below Contraction of fibers of external oblique in females; cor- Poupart’s ligament. responds to crem a steric in males, although it can also be caused in males. Palatal. Irritation of palate. Swallowing. Palmar. Tickling of palm. Contraction of digital flexors.. - te’.’.ar. Same as Knee-jerk. Patellar, Paradox- Percu ing patellar ten- Contraction of the adductor, ic. don with the patient in but not of the quadriceps the dorsal decubitus. muscle. If the patient be in the sitting posture the normal reflex is elicited. Per.is. See Virile. Periosteal. Tapping the bones of Sharp contractions of the forearm or leg. muscles. Significance. Shows integrity of cord from fourth to seventh dorsal nerves. ese Integrity of dorsal region of cord. Disease of spinal cord, £.£-., in some cases of transverse mvelitis. Shows integrity of cord at fourth and fifth lumbar nerves. Rarely present in health; increased in sclerosis of lateral columns of cord. Normal in health. Absent in locomotor ataxia, destructive lesions of lower part of cord, multiple neuritis, affections of the anterior gray corona, infantile paralysis, meningitis, diphtheric paralysis, atrophic palsy, pseudo hypertrophic muscular paralysis, diabetes, etc. Increased in diseases of the pyramidal tracts, in spinal irritability, tumors of brain, cerebrospinal sclerosis, lateral sclerosis, after epileptic lateral seizures convulsions.or uni- Shows that cervical region of cord is normal. Spinal concu ion. the Indicates disease of the lateral columns of spinal cord. TABLE OF Name. How Obtained. Peroneal. Stroke cles on peroneal when tense mus or when the foot is turned inward. Pharyngeal. Irritation of pharynx. Plantar. Stroking sole of foot. Platysma. Pinching the platysma myoides muscle. Pupillary. Exposure of retina to light. Pupillary, para- Stimulation of retina bydoxic. light. Scapular. Irritation of interscapular region. Skin. See Platysma. Sole. Same as Plantar. Spinal. Those reflex actions emanating Superficial. Such as are developed from irr Tendo A chillis, or By striking muscles on anterior part of leg, front-tap contraction. while in extension, the foot being extended by the hand upon the sole. Toe. Strong flexion of great toe. Virile. Sharp percu ion of back of penis, the sheath having been made tense. Wrist-clonus. By pre ing hand backward, causing extreme extension. 551