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Medical Dictionary - Dictionary of Medicine and Human Biology

Medical Dictionary


sign (sin)
1. Any abnormality indicative of disease, discoverable on examination of the patient; an objective indication of disease, in contrast to a symptom, which is a subjective indication of disease. 2. An abbreviation or symbol. 3. In psychology, any object or artifact (stimulus) that represents a specific thing or conveys a specific idea to the person who perceives it. [L. signum, mark] Aaron s. in acute appendicitis, a referred pain or feeling of distress in the epigastrium or precordial region on continuous firm pressure over the McBurney point. Abadie s. of tabes dorsalis insensibility to pressure over the tendo achillis. Abrahams s. an obsolete s.. 1. rales and other adventitious sounds, changes in the respiratory murmurs, and increase in the whispered sound can be heard on auscultation over the acromial end of the clavicle some time before they become audible at the apex; heard primarily in pulmonary tuberculosis affecting the apical portion of the lung; 2. a dull-flat note, i.e., one between the normal dullness at the right apex and absolute flatness, heard on percussion in that region, indicating progress from incipient to advanced tuberculosis. accessory s. a finding frequently but not consistently present in a disease. SYN: assident s.. antecedent s. SYN: prodromic s.. assident s. SYN: accessory s.. Auenbrugger s. an epigastric prominence seen in cases of marked pericardial effusion. Aufrecht s. diminished or noisy breath sounds in the trachea just above the jugular notch, in cases of stenosis. Auspitz s. a finding typical of psoriasis in which removal of a scale leads to pinpoint bleeding. Babinski s. 1. 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); SYN: Babinski phenomenon, Babinski reflex, great-toe reflex, paradoxical extensor reflex, toe phenomenon. 2. in hemiplegia, weakness of the platysma muscle on the affected side, as is evident in such actions as blowing or opening the mouth; 3. when the patient is lying supine, with arms crossed on the front of the chest, and attempts to assume the sitting posture, the thigh on the side of an organic paralysis is flexed and the heel raised, whereas the limb on the sound side remains flat; 4. in hemiplegia, the forearm on the affected side turns to a pronated position when placed in a position of supination. Baccelli s. an obsolete s.: good conduction of the whisper in nonpurulent pleural effusions. SYN: aphonic pectoriloquy. Ballance s. the presence of a dull percussion note in both flanks, constant on the left side but shifting with change of position on the right, said to indicate ruptured spleen; the dullness is due to the presence of fluid blood on the right side but coagulated blood on the left. Bamberger s. 1. jugular pulse in tricuspid insufficiency; 2. SYN: allochiria. 3. dullness on percussion at the angle of the scapula, clearing up as the patient leans forward, indicating pericarditis with effusion. SYN: Bamberger-Pins-Ewart s.. Bamberger-Pins-Ewart s. SYN: Bamberger s.. banana s. the abnormal curvature of the cerebellum noted on ultrasound imaging in a fetus with Arnold-Chiari malformation. Bárány s. in cases of ear disease, in which the vestibule is healthy, injection into the external auditory canal of water below the body temperature will cause rotatory nystagmus toward the opposite side; when the injected fluid is above the body temperature the nystagmus will be toward the injected side; if the labyrinth is diseased or nonfunctional there may be diminished or absent nystagmus. Barré s. a hemiplegic placed in the prone position with the limbs flexed at the knees is unable to maintain the flexed position on the side of the lesion but extends the leg. Bassler s. in chronic appendicitis, pinching the appendix between the thumb and the iliacus muscle causes sharp pain. Bastedo s. an obsolete s.: in chronic appendicitis, pain and tenderness in the right iliac fossa on inflation of the colon with air. Battle s. postauricular ecchymosis in cases of fracture of the base of the skull. B6 bronchus s. in lung radiology, appearance of an air bronchogram of the superior segmental bronchus of the lower lobe because of segmental atelectasis or consolidation. beak s. appearance of the distal esophagus, on a contrast esophagram, in achalasia; also used to describe the proximal pyloric canal on upper GI series in congenital pyloric stenosis. Bechterew s. paralysis of automatic facial movements, the power of voluntary movement being retained. Beevor s. with paralysis of the lower portions of the recti abdominis muscles the umbilicus moves upward. Bergman s. a radiographic finding in which 1) the ureter is dilated distal to a ureteral obstruction and 2) a catheter, passed retrograde, coils in the dilated ureter. SYN: catheter coiling s.. Biederman s. a dusky redness of the lower portion of the anterior pillars of the fauces in certain cases of syphilis. Bielschowsky s. in paralysis of a superior oblique muscle, tilting the head to the side of the involved eye causes that eye to rotate upward. Biot s. abnormal breathing pattern characterized by periods of apnea and periods in which several breaths of similar volume are taken; seen with increased intracranial pressure. Biot breathing s. irregular periods of apnea alternating with four or five deep breaths; seen with increased intracranial pressure. Bird s. the presence of a zone of dullness on percussion with absence of respiratory signs in hydatid cyst of the lung. Bjerrum s. SYN: Bjerrum scotoma. blue dot s. a blue or black spot visible beneath the skin on the cranial aspect of testis or epididymis. This is a torsed testicular appendage and is usually quite tender. Blumberg s. pain felt upon sudden release of steadily applied pressure on a suspected area of the abdomen, indicative of peritonitis. Bonhoeffer s. loss of normal muscle tone in chorea. Bozzolo s. pulsating vessels in the nasal mucous membrane, noted occasionally in thoracic aneurysm. Branham s. bradycardia following compression or excision of an arteriovenous fistula. Braxton Hicks s. irregular uterine contractions occurring after the third month of pregnancy. Broadbent s. a retraction of the thoracic wall, synchronous with cardiac systole, visible anywhere, but particularly in the left posterior axillary line; a s. of adherent pericardium. Brockenbrough s. absolute decrease in pulse pressure of the beat immediately following a premature beat; a s. of idiopathic hypertrophic subaortic stenosis. Brudzinski s. 1. in meningitis, on passive flexion of the leg on one side, a similar movement occurs in the opposite leg. SYN: contralateral reflex, contralateral s.. 2. in meningitis, involuntary flexion of the knees and hips following flexion of the neck while supine. SYN: neck s.. burning drops s. in certain cases of perforated gastric ulcer, a sensation as of drops of hot liquid falling into the abdominal cavity or as of a stream of intensely hot liquid being poured into the cavity. calcium s. in chest radiography, displacement of the line of the calcified intima of the aorta away from its outer wall, a finding in a small percentage of cases of dissection of blood in the aortic media; the expression “displaced intimal calcification” is preferred to the listed term. See aortic dissection. Calkins s. the change of shape of the uterus from discoid to ovoid, indicating placental separation from the uterine wall. Cantelli s. doll's eye s.. Carman s. in gastric radiology, the appearance of a contrast-filled malignant ulcer, which does not extend beyond the line of the gastric wall as a benign ulcer would; also has a thick overhanging rim of tumor tissue. Carnett s. disappearance of abdominal tenderness to palpation when the anterior abdominal muscles are contracted, indicating pain of intra-abdominal origin; its persistence suggests a source in the abdominal wall, which is also indicated when tenderness is caused by gently pinching a fold of skin and fat between the thumb and forefinger. Carvallo s. an increase in the intensity of the pansystolic murmur of tricuspid regurgitation during or at the end of inspiration that distinguishes tricuspid from mitral involvement. catheter coiling s. SYN: Bergman s.. Chaddock s. when the external malleolar skin area is irritated, extension of the great toe occurs in cases of organic disease of the corticospinal reflex paths. SYN: Chaddock reflex. Chadwick s. a bluish discoloration of the cervix and vagina, a s. of pregnancy. chandelier s. colloquial term referring to severe pain elicited during pelvic examination of patients with pelvic inflammatory disease in which the patient responds by reaching upwards towards the ceiling for relief. Chaussier s. severe pain in the epigastrium, a prodrome of eclampsia; may be of central origin or caused by distention of the capsule of liver by hemorrhage. Chvostek s. facial irritability in tetany, unilateral spasm of the orbicularis oculi or oris muscle being excited by a slight tap over the facial nerve just anterior to the external auditory meatus. SYN: Weiss s.. Claybrook s. in rupture of abdominal viscus, transmission of breath and heart sounds through the abdominal wall. clenched fist s. in angina pectoris, pressing of the clenched fist against the chest to indicate the constricting, pressing quality of the pain. Collier s. unilateral or bilateral lid retraction due to midbrain lesion; occurring at any age. See setting sun s., Epstein s.. SYN: Collier tucked lid s.. Collier tucked lid s. SYN: Collier s.. colon cutoff s. radiographic s. of (usually) inflammatory disease preventing distention of the distal transverse colon. Comby s. an early s. of measles, consisting of thin, whitish patches on the gums and buccal mucous membrane, formed of desquamating epithelial cells. comet s. SYN: comet tail s.. comet tail s. in chest radiology, the curved appearance of pulmonary arteries and veins associated with rounded atelectasis, fibrosis associated with organizing pleurisy. SYN: comet s.. commemorative s. a phenomenon pointing to the previous existence of some disease other than the one present at the time. contralateral s. SYN: Brudzinski s. (1) . conventional signs signs that acquire their function through social (linguistic) custom; e.g., words, mathematical symbols. SEE ALSO: symbol (4) . Corrigan s. a full, hard pulse followed by a sudden collapse easily palpated and occurring in aortic regurgitation. SYN: Corrigan pulse. Courvoisier s. SYN: Courvoisier law. crescent s. 1. in radiography of the lung, a crescent of gas near the top of a mass lesion, signifying cavitation with a space above the debris; seen in aspergilloma, hydatidoma; 2. in computed tomography, a high attenuating layer of new blood in an aneurysm; indicates a ruptured abdominal aortic aneurysm; 3. in diagnostic ultrasound, a sonolucent crescentic layer in a tumor mass, typically necrosis in stromal tumors of the small bowel; 4. in diagnostic ultrasound, a hyperechoic crescent, representing the entering limb of an intussusception; also known as crescent-in-a-doughnut; 5. in osteoradiology, a subcortical lucent crescent in the femoral head, signifying osteonecrosis. SYN: meniscus s.. Cruveilhier-Baumgarten s. a murmur over the umbilicus often in the presence of caput medusae, resulting from portal hypertension, usually with hepatic cirrhosis; recanalization of the umbilical vein with reverse blood flow from the liver into the abdominal wall veins creates the murmur. Cullen s. periumbilical darkening of the skin from blood, a s. of intraperitoneal hemorrhage, especially in ruptured ectopic pregnancy. Dalrymple s. retraction of the upper eyelid in Graves disease, causing abnormal wideness of the palpebral fissure. Dance s. a slight retraction in the neighborhood of the right iliac fossa in some cases of intussusception. Danforth s. shoulder pain on inspiration, due to irritation of the diaphragm by a hemoperitoneum in ruptured ectopic pregnancy. Darier s. urtication on stroking of cutaneous lesions of urticaria pigmentosa (mastocytosis). Dejerine s. aggravation of symptoms of root irritation by the acts of coughing, sneezing, or straining to defecate. Delbet s. in a case of aneurysm of a main artery, efficient collateral circulation if the nutrition of the part below is well maintained, despite the fact that the pulse has disappeared. de Musset s. SYN: Musset s.. D'Éspine s. an obsolete s. 1. bronchophony over the spinous processes heard, at a lower level than in health, in pulmonary tuberculosis; 2. an echoed whisper following a spoken word, heard in the stethoscope placed over the seventh cervical or first or second dorsal spine, in cases of tuberculosis of the mediastinal glands. dimple s. in dermatofibroma, dimpling elicited when the lesion is squeezed. doll's eye s. reflex movement of the eyes in the opposite direction to that which the head is moved, e.g., the eyes being lowered as the head is raised, and the reverse (Cantelli s.); an indication of functional integrity of the brainstem tegmental pathways and cranial nerves involved in eye movement. Dorendorf s. fullness of one supraclavicular groove in aneurysm of the aortic arch. double bubble s. in pediatric radiology, appearance of the dilated air-filled stomach and duodenal bulb, associated with duodenal atresia or web, less often midgut volvulus. double ring s. two concentric rings around the optic nerve characteristic of optic nerve hypoplasia. double track s. in pediatric radiology, a less common s. of congenital pyloric stenosis, when barium is caught between mucosal folds in the hypertrophied pylorus. drawer s. in a knee examination, the forward or backward sliding of the tibia under applied stress, which indicates laxity or tear of the anterior (forward slide) or posterior (backward slide) cruciate ligaments of the knee. SYN: drawer test. drooping lily s. in urography, a s. of a double renal collecting system with an obstruction of the upper system depressing the opacified calyces of the lower system so they appear to droop. Drummond s. in certain cases of aortic aneurysm, a puffing sound, synchronous with cardiac systole, heard from the nostrils, when the mouth is closed. Duchenne s. falling in of the epigastrium during inspiration in paralysis of the diaphragm. Dupuytren s. 1. in congenital dislocation, free up and down movement of the head of the femur occurs upon intermittent traction; 2. a crackling sensation on pressure over the bone in certain cases of sarcoma. Duroziez s. SYN: Duroziez murmur. Ebstein s. in pericardial effusion, obtuseness of the cardiohepatic angle on percussion. s. of edema of lower eyelid swelling of the lower lid found in congestive failure, myxedema, or nephrosis. Epstein s. lid retraction in an infant giving it a frightened expression and a “wild glance.” See setting sun s., Collier s.. Ewart s. in large pericardial effusions, an area of dullness with bronchial breathing and bronchophony below the angle of the left scapula. SYN: Pins s.. Ewing s. tenderness at the upper inner angle of the orbit at the point of attachment of the pulley of the superior oblique muscle, denoting closure of the outlet of the frontal sinus. Faget s. a slow pulse with an elevated temperature, often seen in yellow fever. fan s. the spreading apart of the toes in the complete Babinski s.. Fischer s. an obsolete s.: in tuberculosis of the mediastinal or peribronchial glands, after bending the patient's head as far back as possible, auscultation over the manubrium sterni will sometimes reveal a continuous loud murmur caused by the pressure of the enlarged glands on the large mediastinal vessels. SYN: Fischer symptom. fissure s. in perfusion scintigraphy of the lungs, decreased uptake of radionuclide in the periphery of each lobe, making the fissures visible; caused by a variety of diseases and artifacts. flag s. bands of discoloration of hair (reddish, blond, or gray, depending on original color) resulting from fluctuations in nutrition characteristic of kwashiorkor and in diseases with protein depletion such as ulcerative colitis. Forchheimer s. the presence, in German measles, of a reddish maculopapular eruption on the soft palate. Fothergill s. in rectus sheath hematoma, the hematoma produces a mass that does not cross the midline and remains palpable when the rectus muscle is tense. Friedreich s. in adherent pericardium, sudden collapse of the previously distended veins of the neck at each diastole of the heart. Froment s. flexion of the distal phalanx of the thumb when a sheet of paper is held between the thumb and index finger in ulnar nerve palsy. Gaenslen s. pain on hyperextension of the hip with pelvis fixed by flexion of opposite hip; causes a torsion stress at the sacroiliac and lumbosacral joints. Gauss s. marked mobility of the uterus in the early weeks of pregnancy. Glasgow s. a systolic murmur heard over the brachial artery in aneurysm of the aorta. gloved-finger s. in chest radiology, the appearance of mucoid impaction of branching bronchi. Goggia s. the fibrillation of the biceps muscle, when pinched and tapped, is confined to a limited area in cases of debilitating disease, whereas in health it is general. Goldstein toe s. increased space between the great toe and its neighbor, seen in Down syndrome, occasionally in cretinism, and as a normal variant. Goodell s. softening of the cervix and vagina as being usually indicative of pregnancy. Gordon s. SYN: finger phenomenon. Gorlin s. unusual ease in touching the tip of the nose with the tongue; seen in Ehlers-Danlos syndrome. Gower s. use of limb muscles to assume an upright sitting position, with the patient using the hands to “walk” up the legs; seen in conditions of weak pelvic girdle and proximal leg muscles. Graefe s. in Graves disease, lag of the upper eyelid as it follows the rotation of the eyeball downward. SYN: von Graefe s.. Grasset s. normal contraction of the sternocleidomastoid muscle on the paralyzed side in cases of hemiplegia. Grey Turner s. local areas of discoloration about the umbilicus and in the region of the loins, in acute hemorrhagic pancreatitis and other causes of retroperitoneal hemorrhage. Griesinger s. erythema and edema over the posterior part of the mastoid process due to septic thrombosis of the mastoid emissary vein and indicating thrombophlebitis of the sigmoid sinus. Grocco s. 1. acute dilation of the heart following a muscular effort, described in Graves disease; also occurring in various forms of myocardiopathy; 2. extension of the liver dullness several centimeters to the left of the midspinal line in cases of enlargement of that organ. groove s. large, hard, fixed, and extremely tender lymph nodes in the groin above and below the inguinal ligament, with a groove along the ligament; characteristic of lymphogranuloma venereum. Gunn s. 1. compression of the underlying vein at arteriovenous crossings seen ophthalmoscopically in arteriolar sclerosis; 2. on alternate stimulation with light, the pupil of an eye with optic nerve transmission defect constricts poorly or even dilates when stimulated (a relative afferent pupillary defect). SYN: Marcus Gunn s.. Gunn crossing s. retinal arteriovenous crossing with venous compression in hypertensive disease. Guyon s. 1. ballottement of the kidney in cases of nephroptosis, especially when there is also a renal tumor; 2. the hypoglossal nerve lies directly upon the external carotid artery, whereby this vessel may be distinguished from the internal carotid when ligation is necessary. halo s. elevation of the subcutaneous fat layer over the fetal skull in a dead or dying fetus; said to be the most common radiologic s. of fetal death. halo s. of hydrops a discredited radiographic s. of fetal hydrops caused by scalp edema so that a definite corona surrounds the skull. Hamman s. a crunching, rasping sound, synchronous with heart beat, heard over the precordium and sometimes at a distance from the chest in mediastinal emphysema. Hawkins impingement s. pain produced by forced internal rotation of the humerus in 90° of abduction. Hegar s. softening and compressibility of the lower segment of the uterus in early pregnancy (about the seventh week) which, on bimanual examination, is felt by the finger in the vagina as though the neck and body of the uterus were separated, or connected by only a thin band of tissue. Heim-Kreysig s. in adherent pericardium, an indrawing of the intercostal spaces, synchronous with the cardiac systole. SYN: Kreysig s.. Hennebert s. nystagmus produced by pressure applied to a sealed external auditory canal; may be seen in labyrinthine fistula or with intact tympanic membrane in syphilitic involvement of the otic capsule. Higoumenakia s. sternoclavicular swelling in late congenital syphilis. Hill s. in aortic insufficiency, greater systolic blood pressure in the legs than in the arms; normal arterial systolic pressure in the leg is 10–20 mm of Hg above that in the arm, whereas in aortic insufficiency the difference may be 60–100 mm of Hg. SYN: Hill phenomenon. Hoagland s. eyelid edema in infectious mononucleosis. Hoffmann s. 1. in latent tetany mild mechanical stimulation of the trigeminal nerve causes severe pain; 2. flexion of the terminal phalanx of the thumb and of the second and third phalanges of one or more of the fingers when the volar surface of the terminal phalanx of the fingers is flicked. SYN: digital reflex, Hoffmann reflex, snapping reflex. Homans s. pain in the calf when the ankle is slowly and gently dorsiflexed (with the knee bent), indicative of incipient or established thrombosis in the veins of the leg. Hoover signs 1. when a subject lying supine is asked to raise one leg, he or she involuntarily creates counterpressure with the heel of the other leg; if this leg is paralyzed, whatever muscular power is preserved in it will be exerted in this way; or if the patient attempts to lift a paralyzed leg, counterpressure will be made with the other heel, whether any movement occurs in the paralyzed limb or not; not present in hysteria or malingering; 2. a modification in the movement of the costal margins during respiration, caused by a flattening of the diaphragm; suggestive of empyema or other intrathoracic condition causing a change in the contour of the diaphragm. iconic signs signs that acquire their function through similarity to what they signify; e.g., a photograph as a s. of the person in the picture. impingement s. pain in patients with rotator cuff tendinitis or tears within the subacromial space elicited by provocative physical examination maneuvers. indexical signs signs that acquire their function through a causal connection with what they signify; e.g., smoke as a s. of fire. inferior triangle s. in chest radiology, lateral displacement of the mediastinal pleura near the diaphragm, associated with collapse of the upper lobe, usually on the right side. Cf.:superior triangle s.. Jackson s. during quiet respiration the movement of the paralyzed side of the chest may be greater than that of the opposite side, while in forced respiration the paralyzed side moves less than the other. Joffroy s. disorder of the arithmetical faculty (the person being unable to do simple sums in addition or multiplication) in the early stages of organic brain disease. Kehr s. violent pain in the left shoulder in a case of rupture of the spleen. Kerandel s. delayed sensation to pain indicative of African trypanosomiasis. Kernig s. when a subject is supine and the thigh is flexed to a right angle with the axis of the trunk, complete extension of the leg on the thigh is impossible; present in various forms of meningitis. Kestenbaum s. a decrease in the number of arterioles crossing optic disk margins as a s. of optic neuritis. knuckle s. in chest radiography, an abrupt tapering of a large pulmonary artery caused by pulmonary embolism. Kocher s. in Graves disease, on upward gaze, the globe lags behind the movement of the upper eyelid. Kreysig s. SYN: Heim-Kreysig s.. Kussmaul s. in constrictive pericarditis, a paradoxical increase in venous distention and pressure or failure to collapse during inspiration; seen occasionally in effusive-constrictive pericarditis when tamponading pericardial fluid overlies a constricting epicarditis. Lancisi s. a large systolic jugular venous wave caused by tricuspid regurgitation replacing the normal negative systolic trough (“x” descent). Landolfi s. in aortic insufficiency, systolic contraction and diastolic dilation of the pupil. Lasègue s. when a subject is supine with hip flexed and knee extended, dorsiflexion of the ankle causing pain or muscle spasm in the posterior thigh indicates lumbar root or sciatic nerve irritation. Legendre s. in facial hemiplegia of central origin, when the examiner raises the lids of the actively closed eyes the resistance is less on the affected side. lemon s. the ultrasound finding of frontal bone scalloping associated with Arnold-Chiari malformation. Leri s. voluntary flexion of the elbow is impossible in a case of hemiplegia when the wrist on that side is passively flexed. Leser-Trélat s. the sudden appearance and rapid increase in the number and size of seborrheic keratoses with pruritus; associated with internal malignancy. Lhermitte s. sudden electric-like shocks extending down the spine on flexing the head. local s. the characteristic of a sensation that permits distinguishing it from another sensation by locating its position in space. Lorenz s. an obsolete s.: stiffness of the thoracic spine in early pulmonary tuberculosis. Lovibond profile s. SYN: Lovibond angle. Macewen s. percussion of the skull gives a cracked-pot sound in cases of hydrocephalus. SYN: Macewen symptom. Magendie-Hertwig s. skew deviation of the eyes in acute cerebellar lesions. SYN: Magendie-Hertwig syndrome. Magnan s. paresthesia in the psychosis of cocaine addicts, who imagine they have a foreign body, in the shape of a powder or fine sand, under the skin, and that it is constantly changing its position. Magnus s. an obsolete s.: after death, constriction of a limb or one of its segments is followed by venous congestion of the distal part. Mannkopf s. acceleration of the pulse when a painful point is pressed upon. Marañón s. in Graves disease, a vasomotor reaction following stimulation of the skin over the throat. Marcus Gunn s. SYN: Gunn s.. McBurney s. tenderness at site two-thirds of the distance between the umbilicus and the anterior-superior iliac spine; seen in appendicitis. meniscus s. SYN: crescent s.. Metenier s. easy eversion of the upper eyelid in Ehlers-Danlos syndrome. Mirchamp s. a premonitory symptom of mumps; if a strongly flavored substance is placed on the tongue, a painful reflex secretion of saliva occurs in the gland that is the seat of the incipient infection. Möbius s. impairment of ocular convergence in Graves disease. Mosler s. tenderness over the sternum in a patient with acute myeloblastic anemia. Muehrcke s. SYN: Muehrcke bands, under band. Müller s. in aortic insufficiency, rhythmical pulsatory movements of the uvula, synchronous with the heart's action; accompanied by swelling and redness of the velum palati and tonsils. Munson s. in keratoconus, the extra bowing of the lower eyelid caused by the misshapen cornea as the eye rotates downward. Murphy s. pain on palpation of the right subcostal area during inspiration frequently associated with acute cholecystitis. Musset s. in incompetence of the aortic valve, rhythmical nodding of the head, synchronous with the heart beat. SYN: de Musset s.. neck s. SYN: Brudzinski s. (2) . Neer impingement s. pain produced by forceful maximum forward elevation of the upper extremity. Néri s. in hemiplegia, the knee bends spontaneously when the leg is passively extended. Nikolsky s. a peculiar vulnerability of the skin in pemphigus vulgaris; the apparently normal epidermis may be separated at the basal layer and rubbed off when pressed with a sliding motion. objective s. a s. that is evident to the examiner. s. of the orbicularis in hemiplegia, inability to voluntarily close the eye on the paralyzed side except in conjunction with closure of the other eye. SYN: Revilliod s.. Osler s. SYN: Osler node. painful arc s. pain elicited during active abduction of the upper extremity between 60° and 120°. Pastia s. the presence of pink or red transverse lines at the bend of the elbow in the preeruptive stage of scarlatina; they persist through the eruptive stage and remain as pigmented lines after desquamation. SYN: Thomson s.. patellar apprehension s. a physical finding in which forced lateral displacement of the patella produces anxiety and resistance in patients with a history of lateral patellar instability. Payr s. pain on pressure over the sole of the foot; a s. of thrombophlebitis. Perez s. rales audible over the upper part of the chest when the arms are alternately raised and lowered; common in cases of fibrous mediastinitis and also of aneurysm of the aortic arch. Pfuhl s. the pressure of pus within a subphrenic abscess rises during inspiration and falls during expiration, the reverse of what happens in the case of a purulent collection above the diaphragm; when the diaphragm is paralyzed this distinction is lost. physical s. a s. that is observed or elicited by inspection, palpation, percussion, or auscultation. Piltz s. SYN: eye-closure pupil reaction. Pins s. SYN: Ewart s.. Pitres s. 1. SYN: haphalgesia. 2. diminished sensation in the testes and scrotum in tabes dorsalis. placental s. slight endometrial oozing of blood which occurs in certain animals and sometimes in women at the time of implantation of the fertilized ovum; in women, if the blood appears externally it may be mistaken for a scanty menstrual period. Pool-Schlesinger s. SYN: Pool phenomenon (1) . Potain s. in dilation of the aorta, dullness on percussion extending from the manubrium sterni toward the second intercostal space and the third costal cartilage on the right, the upper limit extending from the base of the sternum in the segment of a circle to the right. prodromic s. a s. that appears during the prodrome of a disease. SYN: antecedent s.. pseudo-Graefe s. a lid retraction phenomenon similar to Graefe s., but due to aberrant regeneration of fibers of the oculomotor nerve into the levator of the upper lid. puddle s. a s. of free abdominal fluid: the patient assumes a position on all fours; one flank is percussed by repeated light flicking of constant intensity while a Bowles-type stethoscope is placed over the most dependent portion of the abdomen and gradually moved toward the flank opposite the percussion; a sharp increase in the intensity of the sound picked up by the stethoscope indicates the level of fluid. pyramid s. any symptoms or signs indicative of damage of the pyramidal tracts, such as the Babinski or Gordon s., spastic spinal paralysis, foot clonus, etc. Quant s. a T-shaped depression in the occipital bone occurring in many cases of rickets, especially in infants lying constantly in bed with pressure on the occiput. Quénu-Muret s. in aneurysm, well-maintained collateral circulation indicated by issue of blood when the main artery of the limb is compressed and a puncture is made at the periphery. Quincke s. SYN: Quincke pulse. Ransohoff s. yellow pigmentation in the umbilical region in rupture of the common bile duct. Raynaud s. SYN: acrocyanosis. red, white, and blue s. the contemporaneous occurrence of erythema, ischemia, and necrosis in a wound, as in loxoscelism. Remak s. dissociation of the sensations of touch and of pain in tabes dorsalis and polyneuritis. reversed-three s. on an esophagram of a patient with coarctation of the aorta, the shape of the contrast-filled esophagus caused by the aortic arch (upper convexity) and post-stenotic dilatation (lower convexity); the cusp of the backwards 3 is at the level of the coarctation itself. Revilliod s. SYN: s. of the orbicularis. Ripault s. a s. of death, consisting in a permanent change in the shape of the pupil produced by unilateral pressure on the eyeball. Romaña s. marked edema of one or both eyelids, usually a unilateral palpebral edema, thought to be a sensitization response to the bite of a triatomine bug infected with Trypanosoma cruzi, and a strong suggestion of acute Chagas disease. Romberg s. with feet approximated, the subject stands with eyes open and then closed; if closing the eyes increases the unsteadiness, a loss of proprioceptive control is indicated, and the s. is positive. SYN: Romberg test, rombergism, station test. Rosenbach s. loss of the abdominal reflex in cases of acute inflammation of the viscera. Rossolimo s. SYN: Rossolimo reflex. Rotch s. in pericardial effusion, percussion dullness in the fifth intercostal space on the right. Rovsing s. pain at McBurney point induced in cases of appendicitis, by pressure exerted over the descending colon. Rumpel-Leede s. SYN: capillary fragility test. Russell s. abrasions and scars on the back of the hands of individuals with bulimia, usually due to manual attempts at self-induced vomiting. Sansom s. in mitral stenosis, apparent duplication of the second heart sound. scarf s. s. used in Dubowitz scoring (q.v.) to assess developmental age and muscle tone in neonates. The infant's arm is pulled laterally across the chest; in the hypotonic infant, the elbow will cross the midline; in a term infant with normal tone, the elbow will not reach the midline. Schapiro s. in myocardial weakness, no slowing of the pulse occurs when the patient lies down. Schlesinger s. SYN: Pool phenomenon (1) . Schultze s. in latent tetany, tapping the tongue causes its depression with a concave dorsum. SYN: tongue phenomenon. scimitar s. a curvilinear structure seen radiographically in the lung and associated with anomalous pulmonary venous drainage, suggesting the sickle shape of a saber; also used to refer to the scalloped shape of the sacrum in spinal dysraphism with anterior meningocele. Seeligmüller s. contraction of the pupil on the affected side in facial neuralgia. Seidel s. a sickle-shaped scotoma appearing as an upward or downward extension of the blind spot. sentinel loop s. in gastrointestinal radiology, dilation of a segment of large or small intestine, indicative of localized ileus from nearby inflammation. setting sun s. retraction of the upper lid without upgaze so that the iris seems to “set” below the lower lid; suggestive of neurologic damage in the newborn, but usually clears up without sequelae. See Collier s., Epstein s.. S s. of Golden in pulmonary radiology, the combination of an atelectatic lobe and a central obstructing mass produces a concavity and a convexity, like the letter “S.” Shibley s. on auscultation of the chest, the spoken sound “e” is heard as “ah” over an area of pulmonary consolidation or immediately above a pleural effusion. shoulder apprehension s. a physical finding in which placement of the humerus in the position of abduction to 90° and maximum external rotation produces anxiety and resistance in patients with a history of anterior glenohumeral instability. SYN: anterior apprehension test (1) . Siegert s. shortness and inward curvature of the terminal phalanges of the fifth fingers in Down syndrome. silhouette s. of Felson in pulmonary radiology, the obliteration of a normal air-soft tissue interface, such as the cardiac silhouette, when fluid fills the adjacent part of the lung. Skoda s. SYN: skodaic resonance. Snellen s. bruit heard on auscultation over the eye in a patient with Graves disease, due to the hyperdynamic circulation. spinal s. in pleurisy, the spinal muscles are in a state of tonic contraction on the affected side. spine s. resistance to flexion of the spine in cases of meningitis. Steinberg thumb s. in Marfan syndrome, when the thumb is held across the palm of the same hand, it projects well beyond the ulnar surface of the hand. Stellwag s. infrequent and incomplete blinking in Graves disease. Sternberg s. unilateral tenderness or discomfort on palpation of the shoulder girdle muscles in a patient with pleurisy on that side. Stewart-Holmes s. in cerebellar disease, the inability to check a movement when passive resistance is suddenly released. SYN: rebound phenomenon (1) . Stierlin s. repeated emptying of the cecum, seen radiographically, with barium remaining in the terminal part of the ileum and in the transverse colon; due to irritation of the cecum, sometimes caused by tuberculous cecitis (typhilitis). Straus s. in facial paralysis, if an injection of pilocarpine is followed by sweating on the affected side later than on the other, the lesion is peripheral. string s. in pediatric gastrointestinal radiology, the narrowed pyloric canal seen with congenital pyloric stenosis; also used to describe a narrowed segment in regional ileitis on small bowel series. subjective s. a s. that is perceived only by the patient. Sumner s. a slight increase in tonus of the abdominal muscles, an early indication of inflammation of the appendix, stone in the kidney or ureter, or a twisted pedicle of an ovarian cyst; it is detected by exceedingly gentle palpation of the right or left iliac fossa. superior triangle s. in chest radiology, widening of the superior mediastinum, usually on the right, associated with collapse of the lower lobe producing traction on the mediastinal pleura. Cf.:inferior triangle s.. ten Horn s. pain caused by gentle traction on the right spermatic cord, indicative of appendicitis. Thomson s. SYN: Pastia s.. Tinel s. a sensation of tingling, or of “pins and needles,” felt at the lesion site or more distally along the course of a nerve when the latter is percussed; indicates a partial lesion or early regeneration in the nerve. SYN: distal tingling on percussion. Toma s. to distinguish between inflammatory and noninflammatory ascites: in inflammatory conditions of the peritoneum, the mesentery contracts, drawing the intestines over to the right side; consequently, with the patient supine, tympany is elicited on the right side, dullness on the left. Topolanski s. congestion of the pericorneal region of the eye in Graves disease. Tournay s. SYN: Tournay phenomenon. Traube s. a double sound or murmur heard in auscultation over arteries (particularly the femoral arteries) in significant aortic regurgitation. Trendelenburg s. a physical examination finding associated with various hip abnormalities ( e.g., congenital dislocation, hip abductor weakness, rheumatic arthritis, osteoarthritis) in which the pelvis sags on the side opposite the affected side during single leg stance on the affected side; during gait, compensation occurs by leaning the torso toward the involved side during stance phase on the affected extremity. SYN: Trendelenburg gait. Tresilian s. a reddish prominence at the orifice of Stenson duct, noted in mumps. trough s. an anteromedial glenoid defect resultant from posterior shoulder dislocation. Trousseau s. in latent tetany, the occurrence of carpopedal spasm accompanied by paresthesia elicited when the upper arm is compressed, as by a tourniquet or a blood pressure cuff. Trunecek s. palpable impulse of the subclavian artery near the point of origin of the sternomastoid muscle in cases of aortic sclerosis. Uhthoff s. See Uhthoff symptom. Vierra s. yellowing and canalization of the nail in fogo selvagem. Vipond s. a generalized adenopathy occurring during the period of incubation of various of the exanthemas of childhood, affording an early diagnostic s. in a case of known exposure. vital signs determination of temperature, rate of breathing, and level of blood pressure. von Graefe s. SYN: Graefe s.. Weber s. SYN: Weber syndrome. Weiss s. SYN: Chvostek s.. Wernicke s. SYN: Wernicke reaction. Westermark s. in chest radiography, decreased lung markings from oligemia caused by pulmonary embolism. Wilder s. a slight twitch of the eyeball when changing its movement from abduction to adduction or the reverse, noted in Graves disease. Winterbottom s. swelling of the posterior cervical lymph nodes, characteristic of early stages of African trypanosomiasis; useful for surveys or control of migrations from endemic areas of persons with preclinical infections. wrist s. in Marfan syndrome, when the wrist is gripped with the opposite hand, the thumb and fifth finger overlap appreciably.

signal (sig′nal)
1. Something that causes an action. 2. A DNA template sequence that alters RNA polymerase transcription. 3. The end product observed when a specific sequence of DNA or RNA is deleted by some method. arrest s. a DNA sequence that causes arrest of RNA polymerase transcription. contralateral routing of signals a hearing aid configuration for greater hearing loss in one ear than the other in which sound is picked up by the microphone at the worse hearing ear and delivered to the better hearing ear. pause s. a DNA sequence that causes pausing of RNA polymerase transcription. termination s. SYN: termination codon.

signature (sig′na-choor, -toor)
The part of a prescription containing the directions to the patient. [Mediev. L. signatura, fr. L. signum, a sign, mark]

Signed English
A system of communication that is a semantic representation of English in which American Sign Language signs are used in English word order and additional signs are used for inflection; used principally in the education of children younger than 6 years.

significant (sig-nif′i-kant)
In statistics, denoting the reliability of a finding or, conversely, the probability of the finding being the result of chance (generally less than 5%). [L. significo, to make known, signify, fr. signum, sign, + facio, to make]

siguatera (seg-wa-ta′a)
See ciguatera.

Abbreviation for somatotropin release-inhibiting hormone.

Robert H., U.S. biochemist, *1915. See Porter-S. chromogens, under chromogen, Porter-S. reaction, Porter-S. chromogens test.

sildenafil (sil-den′a-fil)
A selective inhibitor of cGMP-specific phosphodiesterase type 5 (PDE5); relaxes the muscle in the penis, resulting in greater blood flow and erection; used to treat male impotence; potentiates the hypotensive effects of nitrates.

silent (si′lent)
Producing no detectable signs or symptoms, said of certain diseases or morbid processes.

silica (sil′i-ka)
The chief constituent of sand, hence of glass. SYN: silicic anhydride, silicon dioxide. [Mod. L. fr. L. silex (silic-), flint] s. gel a precipitated form of silicic acid, used for adsorption of various gases.

silicate (sil′i-kat)
1. A salt of silicic acid. 2. The term sometimes applied to dental restorations of synthetic porcelain.

silicatosis (sil′i-ka-to′sis)
SYN: silicosis.

siliceous (si-lish′us)
Containing silica. SYN: silicious.

silicic (si-lis′ik)
Relating to silica or silicon.

silicic acid
Obtained in water as a colloid by treating silicates; precipitated s. is silica gel.

silicic anhydride
SYN: silica.

silicious (si-lish′us)
SYN: siliceous.

silicoanthracosis (sil′i-ko-an′thra-ko- sis)
A pneumoconiosis consisting of a combination of silicosis and anthracosis, seen in hard coal miners.

silicofluoride (sil′i-ko-flor′id)
A compound of silicon and fluorine with another element.

silicon (Si) (sil′i-kon)
A very abundant nonmetallic element, atomic no. 14, atomic wt. 28.0855, occurring in nature as silica and silicates; in pure form, used as a semiconductor and in solar batteries; also found in certain polysaccharide structures in mammary tissue. [L. silex, flint] amorphous s. light-sensitive material used in digital radiography (q.v.) and fluoroscopy (q.v.).

silicon dioxide
SYN: silica. colloidal s. a submicroscopic fumed silica prepared by the vapor-phase hydrolysis of a silicon compound; used as a tablet diluent and as a suspending and thickening agent.

silicone (sil′i-kon)
A polymer of organic silicon oxides, which may be a liquid, gel, or solid, depending on the extent of polymerization; formerly widely used in surgical implants, in intracorporeal tubes to conduct fluids, as dental impression material, as a grease or sealing substance, as a coating on the inside of glass vessels for blood collection, and in various ophthalmological procedures. s.-related disease problems disease allegedly resulting from release of s. into the body.

silicoproteinosis (sil′i-ko-pro′te-i-no′sis)
An acute pulmonary disorder, radiographically and histologically similar to pulmonary alveolar proteinosis, resulting from relatively short exposure to high concentrations of silica dust; pulmonary symptoms are of rapid onset and the condition is invariably fatal.

silicosiderosis (sil′i-ko-sid′er-o′sis)
SYN: siderosilicosis.

silicosis (sil-i-ko′sis)
A form of pneumoconiosis resulting from occupational exposure to and inhalation of silica dust over a period of years; characterized by a slowly progressive fibrosis of the lungs, which may result in impairment of lung function; s. predisposes to pulmonary tuberculosis. SYN: pneumosilicosis, silicatosis, stone-mason's disease. [L. silex, flint, + -osis, condition]

silicotuberculosis (sil′i-ko-too-ber-ku-lo′sis)
Silicosis associated with tuberculous pulmonary lesions.

siliqua olivae (sil′i-kwa o-li′ve)
The arcuate fibers, which appear to encircle the inferior olive in the medulla oblongata. [L. the husk of the olive]

The fibers or filaments obtained from the cocoon of the silkworm. floss s. SYN: dental floss. surgical s. thread prepared from the cocoon filaments of glutinous gum that are spun by the mulberry silkworm Bombyx mori; can be obtained in various sizes and used as suture material. virgin s. an extremely fine ophthalmic suture material consisting of two to seven natural s. filaments bonded together by sericin, a natural adhesive.

Henry K., U.S. pediatrician, *1918. See S.-Russell dwarfism, S.-Russell syndrome.

silver (Ag)
L. argentum;a metallic element, atomic no. 47, atomic wt. 107.8682. Many salts have clinical applications. SYN: argentum. [A.S. seolfor] s. chloride used in the preparation of antiseptic s. preparations. colloidal s. iodide an antiseptic used for treatment of inflammation of the mucous membranes. s. fluoride AgF2&chmpnt;H2O;an antiseptic. fused s. nitrate SYN: toughened s. nitrate. s. iodate a reagent for the determination of chloride. s. lactate has been used as an astringent and antiseptic. mild s. protein a complex prepared by the reaction of s. oxide with either gelatin or serum albumin. Black shiny crystals liberate s. and it was formerly widely used as a topical anti-infective on mucous membranes. Contains 19–25% s., only a small fraction of which is ionizable. Can produce black or brown pigmentation due to deposition of reduced s. in the tissues. SYN: argyrol, silvol. s. nitrate an antiseptic and astringent; used externally, in solution, in the prevention of ophthalmia neonatorum (currently penicillin is often used); also used in the special staining of the nervous system, spirochetes, reticular fibers, Golgi apparatus, nucleolar organizer region, and calcium. s. oxide has been used in epilepsy and chorea; it is explosive when mixed with readily combustible substances. s. picrate an ionizable salt of s.; has been used in the treatment of trichomoniasis and moniliasis of the vagina. strong s. protein a compound of s. and protein containing not less than 7.5 and not more than 8.5% of s.; used externally as an antiseptic, devoid of astringent and nearly so of irritant properties. s. sulfadiazine the s. derivative of sulfadiazine, used externally as a topical antibacterial agent in preventing and treating infections in burns. toughened s. nitrate s. nitrate mixed with s. chloride and allowed to dry. Usually applied to the ends of small wooden applicator sticks or made available as pencils. These are used after wetting as a caustic chemical for the removal of warts. SYN: fused s. nitrate, lunar caustic.

silver impregnation
Silver complexes employed to demonstrate reticulin in normal and diseased tissues, as well as neuroglia, neurofibrillae, argentaffin cells, and Golgi apparatus.

Leslie, U.S. engineer, 1914–1966. See S.-Lilly pneumotachograph.

William A., 20th century U.S. pediatrician. See Caffey-S. syndrome.

Nils G., Swedish orthopedist, 1888–1957. See S. syndrome.

silvol (sil′vol)
SYN: mild silver protein.

simethicone (si-meth′i-kon)
A mixture of dimethyl polysiloxanes and silica gel; an antiflatulent.

similia similibus curantur (si-mil′e-a si-mil′i-bus ker-an′ter)
The homeopathic concept expressing the law of similars (literally, “likes are cured by likes”), the doctrine that any drug capable of producing morbid symptoms in the healthy will remove similar symptoms occurring as an expression of disease. Another reading of the concept, employed by Hahnemann, the founder of homeopathy, is similia similibus curentur, “let likes be cured by likes.” [L. likes are cured by likes]

similimum, simillimum (si-mil′i-mum)
In homeopathy, the remedy indicated in a certain case because the same drug, when given to a healthy person, will produce the symptom complex most nearly approaching that of the disease in question. [L. simillimus, most like, superl. of similis, like]

Morris, German physician, 1855–1925. See S. disease.

James S., U.S. bacteriologist, 1890–1954. See S. citrate medium.

Gustav, German surgeon, 1824–1876. See S. position.

Richard, 20th century U.S. oncologist. See Norton-S. hypothesis.

Théodore, French physician, 1873–1961. See Binet-S. scale.

Pierre J.C., Belgian obstetrician, 1816–1846. See S. bands, under band, S. ligaments, under ligament.

Arthur, German physician, *1877. See S. disease.

Simonsiella (si′mon-se-el′ah)
Genus of nonphotosynthetic, nonfruiting, Gram-negative, chemoorganotrophic, gliding bacteria that exist as multicellular filaments with the long axis of individual cells perpendicular to the long axis of the filament. The cells are flattened and curved to yield a convex-concave, crescent shaped symmetry. Isolated from the oral cavity of mammals. Type species is S. muelleri.

simple (sim′pl)
1. Not complex or compound. 2. In anatomy, composed of a minimum number of parts. 3. A medicinal herb. [L. simplex]

Simplexvirus (sim′pleks-vi′rus)
SYN: herpes simplex.

Simplified Oral Hygiene Index (OHI-S)
An index that measures the current oral hygiene status based upon the amount of debris and calculus occurring on six representative tooth surfaces in the mouth; often used in field surveys of periodontal disease.

Sir James Y., Scottish obstetrician, 1811–1870. See S. uterine sound, S. forceps.

William, British civil engineer, &dag;1917.

James Marion, U.S. gynecologist, 1813–1883. See S. position, S. uterine sound.

simulation (sim-u-la′shun)
1. Imitation; said of a disease or symptom that resembles another, or of the feigning of illness as in factitious illness or malingering. 2. In radiation therapy, use of a geometrically similar radiographic system or computer to plan the location of therapy ports. [L. simulatio, fr. simulo, pp. -atus, to imitate, fr. similis, like] computer s. SYN: computer model.


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