Medical sign
A medical sign is an objective
Objectivity (science)
Objectivity in science is a value that informs how science is practiced and how scientific truths are created. It is the idea that scientists, in attempting to uncover truths about the natural world, must aspire to eliminate personal biases, a priori commitments, emotional involvement, etc...

 indication of some medical fact or characteristic that may be detected by a physician
A physician is a health care provider who practices the profession of medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury and other physical and mental impairments...

 during a physical examination
Physical examination
Physical examination or clinical examination is the process by which a doctor investigates the body of a patient for signs of disease. It generally follows the taking of the medical history — an account of the symptoms as experienced by the patient...

 of a patient
A patient is any recipient of healthcare services. The patient is most often ill or injured and in need of treatment by a physician, advanced practice registered nurse, veterinarian, or other health care provider....


Signs may have no meaning for, and can even go unnoticed by, the patient, but may be full of meaning for the healthcare provider, and are often significant in assisting a healthcare provider in diagnosis
Medical diagnosis
Medical diagnosis refers both to the process of attempting to determine or identify a possible disease or disorder , and to the opinion reached by this process...

 of medical condition(s) responsible for the patient's symptom
A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...


Examples include elevated blood pressure
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...

, a clubbing of the fingers (which may be a sign of lung disease, or many other things), and arcus senilis
Arcus senilis
Arcus senilis is a white or gray, opaque ring in the corneal margin , or white ring around the iris. It is present at birth, but then fades; however, it is quite commonly present in the elderly...


The term sign is not to be confused with the term indication
Indication (medicine)
In medicine, an indication is a valid reason to use a certain test, medication, procedure, or surgery. The opposite of indication is contraindication.-Drugs:...

, which denotes a valid reason for using some treatment.

Signs and semiotics

The art of interpreting clinical signs was originally called semiotics (a term now used for the study of sign communication in general
Semiotics, also called semiotic studies or semiology, is the study of signs and sign processes , indication, designation, likeness, analogy, metaphor, symbolism, signification, and communication...

) in English. This term, then written semeiotics (derived from the Greek adjective σημειοτικός: semeiotikos, "to do with signs"), was first used in English in 1670 by Henry Stubbes
Henry Stubbes
-Life:He was born in Partney, Lincolnshire, and educated at Westminster School. Given patronage as a child by the Puritan, Henry Vane the Younger, he obtained a scholarship to Christ Church, Oxford, from which he graduated in 1653...

 (1631–1676), to denote the branch of medical science relating to the interpretation of signs:
…nor is there any thing to be relied upon in Physick, but an exact knowledge of medicinal phisiology (founded on observation, not principles), semeiotics, method of curing, and tried (not excogitated, not commanding) medicines…

Eponymous signs

Historically, medical signs were named after
An eponym is the name of a person or thing, whether real or fictitious, after which a particular place, tribe, era, discovery, or other item is named or thought to be named...

 the physician
A physician is a health care provider who practices the profession of medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury and other physical and mental impairments...

s who first described them.

Signs versus symptoms

Signs are different from symptoms, the subjective experiences, such as fatigue
Fatigue (physical)
Fatigue is a state of awareness describing a range of afflictions, usually associated with physical and/or mental weakness, though varying from a general state of lethargy to a specific work-induced burning sensation within one's muscles...

, that patients might report to their examining physician.

For convenience, signs are commonly distinguished from symptoms as follows: Both are something abnormal, relevant to a potential medical condition, but a symptom is experienced and reported by the patient, while a sign is discovered by the physician during examination of the patient.

A slightly different definition views signs as any indication of a medical condition that can be objectively observed (i.e., by someone other than the patient), whereas a symptom is merely any manifestation of a condition that is apparent to the patient (i.e., something consciously affecting the patient). From this definition, it can be said that an asymptomatic patient is uninhibited by disease. However, a doctor may discover the sign hypertension in an asymptomatic patient, who does not experience "dis-ease", and the sign indicates a disease state that poses a hazard to the patient. With this set of definitions, there is some overlap – certain things may qualify as both a sign and a symptom (e.g., a bloody nose).

Lester S. King, author of Medical Thinking, argues that an "essential feature" of a sign is that there is both a sign [or "signifier"] and a "thing signified". And, because "the essence of a sign is to convey information", it can only be a sign, properly speaking, if it has meaning. Therefore, "a sign ceases to be a sign when you cannot read it". A person, who has and exercises the knowledge required to understand the significance or indication or meaning of the sign, is necessary for something to be a complete sign. A physical phenomenon that is not actually interpreted as a sign pointing to something else is, in medicine, merely a symptom. Thus, King rejects "these present-day views [distinguishing signs from symptoms based on patient-subjective versus clinician-objective], however widely accepted, as quite faulty, at variance not only with ordinary usage but with the entire history of medicine."

Types of signs

Medical signs may be classified by the type of inference that may be made from their presence, for example:
  • Prognostic signs (from progignṓskein, προγιγνώσκειν, "to know beforehand"): signs that indicate the outcome of the current bodily state of the patient (i.e., rather than indicating the name of the disease). Prognostic signs always point to the future. Perhaps the most famous prognostic sign is the facies Hippocratica:

"[If the patient's facial] appearance may be described thus: the nose sharp, the eyes sunken, the temples fallen in, the ears cold and drawn in and their lobes distorted, the skin of the face hard, stretched and dry, and the colour of the face pale or dusky.… and if there is no improvement within [a prescribed period of time], it must be realized that this sign portends death."

  • Anamnestic
    Medical history
    The medical history or anamnesis of a patient is information gained by a physician by asking specific questions, either of the patient or of other people who know the person and can give suitable information , with the aim of obtaining information useful in formulating a diagnosis and providing...

    (from anamnēstikós, ἀναμνηστικός, "able to recall to mind"): signs that (taking into account the current state of a patient's body), indicate the past existence of a certain disease or condition. Anamnestic signs always point to the past. (Whenever we see a man walking with a particular gait, with one arm paralysed in a particular way, we say "This man has had a stroke"; and, if we see a woman in her late 50s with one arm distorted in a particular way, we say "She had polio as a child".)

  • Diagnostic
    Medical diagnosis
    Medical diagnosis refers both to the process of attempting to determine or identify a possible disease or disorder , and to the opinion reached by this process...

    (from diagnōstikós, διαγνωστικός, "able to distinguish"): signs that lead to the recognition and identification of a disease (i.e., they indicate the name of the disease).

  • Pathognomonic
    Pathognomonic is a term, often used in medicine, that means characteristic for a particular disease. A pathognomonic sign is a particular sign whose presence means that a particular disease is present beyond any doubt...

    (from pathognomonikós, παθογνωμονικός, "skilled in diagnosis", derived from páthos, πάθος, "suffering, disease", and gnṓmon, γνώμον, "judge, indicator"): the particular signs whose presence means, beyond any doubt, that a particular disease is present. They represent a marked intensification of a diagnostic sign. (An example would be the palmar xanthoma
    A xanthoma , from Greek xanthos, ξανθος, "yellow", is a deposition of yellowish cholesterol-rich material in tendons or other body parts in various disease states...

    ta seen on the hands of people suffering from hyperlipoproteinaemia.) Singular pathognomonic signs are relatively uncommon.

"[Thus] a symptom is a phenomenon, caused by an illness and observable directly in experience. We may speak of it as a manifestation of illness. When the observer reflects on that phenomenon and uses it as a base for further inferences, then that symptom is transformed into a sign. As a sign it points beyond itself — perhaps to the present illness, or to the past or to the future. That to which a sign points is part of its meaning, which may be rich and complex, or scanty, or any gradation in between. In medicine, then, a sign is thus a phenomenon from which we may get a message, a message that tells us something about the patient or the disease. A phenomenon or observation that does not convey a message is not a sign. The distinction between signs and symptom rests on the meaning, and this is not perceived but inferred."

Technological development creating signs detectable only by physicians

Prior to the nineteenth century there was little difference in the powers of observation between physician and patient. Most medical practice was conducted as a joint co-operative interaction between the physician and the patient as equals. Whilst each noticed much the same things, the physician had a more informed interpretation of those things: "the physicians knew what the findings meant and the layman did not".

Advances in the 19th century

However, the patient was gradually removed from the medical interaction due to significant technological advances such as:
  • The 1808 introduction of the percussion
    Percussion (medicine)
    Percussion is a method of tapping on a surface to determine the underlying structure, and is used in clinical examinations to assess the condition of the thorax or abdomen. It is one of the four methods of clinical examination, together with inspection, palpation and auscultation...


The techniques, which had been first described by the Viennese physician Leopold Auenbrugger
Leopold Auenbrugger
Josef Leopold Auenbrugger or Leopold von Auenbrugg , Austrian physician who invented percussion as a diagnostic technique. On the strength of this discovery, he is considered one of the founders of modern medicine.-Biography:Auenbrugger was a native of Graz in Styria, an Austrian province...

 (1722–1809) in 1761, became far more widely known following the publication of Jean-Nicolas Corvisart
Jean-Nicolas Corvisart
Jean-Nicolas Corvisart was an important figure in the history of French medicine. Born in the French village of Dricourt, Ardennes in 1755, Corvisart gained early notoriety for his translation of Leopold von Auenbrugg's Inventum Novum from Latin into French...

's translation of Auenbrugger's work in 1808.
  • The 1819 introduction by René Laënnec
    René Laennec
    René-Théophile-Hyacinthe Laennec was a French physician. He invented the stethoscope in 1816, while working at the Hôpital Necker and pioneered its use in diagnosing various chest conditions....

     (1781–1826) of the technique of auscultation
    Auscultation is the term for listening to the internal sounds of the body, usually using a stethoscope...

     (using a stethoscope
    The stethoscope is an acoustic medical device for auscultation, or listening to the internal sounds of an animal body. It is often used to listen to lung and heart sounds. It is also used to listen to intestines and blood flow in arteries and veins...

     to listen to the circulatory and respiratory functions of the body). Laënnec's publication was translated into English, 1821–1834, by John Forbes
    John Forbes (physician)
    Sir John Forbes FRCP FRS was a distinguished Scottish physician, famous for his translation of the classic French medical text, De L'Auscultation Mediate by René Laennec, the inventor of the stethoscope...


  • The 1846 introduction by surgeon John Hutchinson
    John Hutchinson
    John Hutchinson may refer to:*John Hutchinson , leader in the 17th century Puritan revolt in Britain*John Hutchinson , English writer...

     (1811–1861) of the spirometer
    A spirometer is an apparatus for measuring the volume of air inspired and expired by the lungs. It is a precision differential pressure transducer for the measurements of respiration flow rates. The spirometer records the amount of air and the rate of air that is breathed in and out over a...

    , an apparatus for assessing the mechanical properties of the lungs via measurements of forced exhalation and forced inhalation. (The recorded lung volumes
    Lung volumes
    Lung volumes and lung capacities refer to the volume of air associated with different phases of the respiratory cycle. Lung volumes are directly measured...

     and air flow rates are used to distinguish between
    Spirometry is the most common of the pulmonary function tests , measuring lung function, specifically the measurement of the amount and/or speed of air that can be inhaled and exhaled...

     restrictive disease (in which the lung volumes are decreased: e.g., cystic fibrosis
    Cystic fibrosis
    Cystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...

    ) and obstructive diseases (in which the lung volume is normal but the air flow rate is impeded; e.g., emphysema
    Emphysema is a long-term, progressive disease of the lungs that primarily causes shortness of breath. In people with emphysema, the tissues necessary to support the physical shape and function of the lungs are destroyed. It is included in a group of diseases called chronic obstructive pulmonary...


  • The 1851 invention by Hermann von Helmholtz
    Hermann von Helmholtz
    Hermann Ludwig Ferdinand von Helmholtz was a German physician and physicist who made significant contributions to several widely varied areas of modern science...

     (1821–1894) of the ophthalmoscope, which allowed physicians to examine the inside of the human eye.

  • The 1895 clinical use of X-ray
    X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

    s which began almost immediately after they had been discovered that year by Wilhelm Conrad Röntgen
    Wilhelm Conrad Röntgen
    Wilhelm Conrad Röntgen was a German physicist, who, on 8 November 1895, produced and detected electromagnetic radiation in a wavelength range today known as X-rays or Röntgen rays, an achievement that earned him the first Nobel Prize in Physics in 1901....


  • The 1896 introduction of the sphygmomanometer
    A sphygmomanometer or blood pressure meter is a device used to measure blood pressure, comprising an inflatable cuff to restrict blood flow, and a mercury or mechanical manometer to measure the pressure. It is always used in conjunction with a means to determine at what pressure blood flow is just...

    , designed by Scipione Riva-Rocci
    Scipione Riva-Rocci
    Scipione Riva-Rocci was an Italian internist and pediatrician who was a native of Almese. He earned his medical degree in 1888 from the University of Turin, and from 1900 until 1928 was director of the hospital in Varese.He developed an easy to use version of the sphygmomanometer...

     (1863–1937), to measure blood pressure
    Blood pressure
    Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...


Alteration of the relationship between physician and patient

The introduction of the techniques of percussion and auscultation into medical practice altered the relationship between physician and patient in a very significant way, specifically because these techniques relied almost entirely upon the physician listening.

Not only did this greatly reduce the patient's capacity to observe and contribute to the process of diagnosis, it also meant that the patient was often instructed to stop talking, and remain silent.

As these sorts of evolutionary changes continued to take place in medical practice, it was increasingly necessary to uniquely identify data that was accessible only to the physician, and to be able to differentiate those observations from others that were also available to the patient, and it just seemed natural to use "signs" for the class of physician-specific data, and "symptoms" for the class of observations available to the patient.

King proposes a more advanced notion; namely, that a sign is something that has meaning, regardless of whether it is observed by the physician or reported by the patient:

Signs as tests

In some senses, the process of diagnosis is always a matter of assessing the likelihood that a given condition is present in the patient. In a patient who presents with haemoptysis (coughing up blood), the haemoptysis is very much more likely to be caused by respiratory disease than by the patient having broken their toe. Each question in the history taking allows the medical practitioner to narrow down their view of the cause of the symptom, testing and building up their hypotheses as they go along.

Examination, which is essentially looking for clinical signs, allows the medical practitioner to see if there is evidence in the patient's body to support their hypotheses about the disease that might be present.

A patient who has given a good story to support a diagnosis of tuberculosis
Tuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body...

 might be found, on examination, to show signs that lead the practitioner away from that diagnosis and more towards sarcoidosis
Sarcoidosis , also called sarcoid, Besnier-Boeck disease or Besnier-Boeck-Schaumann disease, is a disease in which abnormal collections of chronic inflammatory cells form as nodules in multiple organs. The cause of sarcoidosis is unknown...

, for example. Examination for signs tests the practitioner's hypotheses, and each time a sign is found that supports a given diagnosis, that diagnosis becomes more likely.

Special tests (blood tests, radiology
Radiology is a medical specialty that employs the use of imaging to both diagnose and treat disease visualized within the human body. Radiologists use an array of imaging technologies to diagnose or treat diseases...

, scans, a biopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...

, etc.) also allow a hypothesis to be tested. These special tests are also said to show signs in a clinical sense. Again, a test can be considered pathognonomic for a given disease, but in that case the test is generally said to be "diagnostic" of that disease rather than pathognonomic. An example would be a history of a fall from a height, followed by a lot of pain in the leg. The signs (a swollen, tender, distorted lower leg) are only very strongly suggestive of a fracture; it might not actually be broken, and even if it is, the particular kind of fracture and its degree of dislocation need to be known, so the practitioner orders an x-ray. The x-ray film shows a fractured tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....

, so the film is said to be diagnostic of the fracture.

Examples of signs

  • Ascites
    Ascites is a gastroenterological term for an accumulation of fluid in the peritoneal cavity.The medical condition is also known as peritoneal cavity fluid, peritoneal fluid excess, hydroperitoneum or more archaically as abdominal dropsy. Although most commonly due to cirrhosis and severe liver...

     (fluid in the abdomen)
  • Cachexia
    Cachexia or wasting syndrome is loss of weight, muscle atrophy, fatigue, weakness, and significant loss of appetite in someone who is not actively trying to lose weight...

     (loss of weight, muscle atrophy)
  • Caput medusae
    Caput medusae
    Caput medusae is the appearance of distended and engorged paraumbilical veins, which are seen radiating from the umbilicus across the abdomen to join systemic veins...

     (dilated umbilical veins)
  • Clubbing (deformed nails)
  • Cough
    A cough is a sudden and often repetitively occurring reflex which helps to clear the large breathing passages from secretions, irritants, foreign particles and microbes...

  • Death rattle
    Death rattle
    A death rattle is a medical term that describes the sound produced by someone who is near death when saliva accumulates in the throat. Those who are dying may lose their ability to swallow, resulting in such an accumulation...

     (last moments of life in a person/animal)
  • Fever
    Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...

  • Gynecomastia
    Gynecomastia or Gynaecomastia, , is the abnormal development of large mammary glands in males resulting in breast enlargement. The term comes from the Greek γυνή gyné meaning "woman" and μαστός mastós meaning "breast"...

     (excessive breast tissue in males)
  • Hemoptysis
    Hemoptysis or haemoptysis is the expectoration of blood or of blood-stained sputum from the bronchi, larynx, trachea, or lungs Hemoptysis or haemoptysis is the expectoration (coughing up) of blood or of blood-stained sputum from the bronchi, larynx, trachea, or lungs Hemoptysis or haemoptysis ...

     (blood-stained sputum)
  • Hepatosplenomegaly
    Hepatosplenomegaly is the simultaneous enlargement of both the liver and the spleen . Hepatosplenomegaly can occur as the result of acute viral hepatitis or infectious mononucleosis, or it can be the sign of a serious and life threatening lysosomal storage disease...

     (enlarged liver and spleen)
  • Icterus ("jaundice")
  • Lymphadenopathy
    Lymphadenopathy is a term meaning "disease of the lymph nodes." It is, however, almost synonymously used with "swollen/enlarged lymph nodes". It could be due to infection, auto-immune disease, or malignancy....

     (swollen lymph nodes)
  • Palmar erythema
    Palmar erythema
    Palmar erythema is reddening of the palms at the thenar and hypothenar eminences.-Causes:It is associated with various physiological as well as pathological changes, the principal one of which is portal hypertension. It is also seen in patients with liver dysfunction, such as chronic liver disease...

     (reddening of hands)
  • Splenomegaly
    Splenomegaly is an enlargement of the spleen. The spleen usually lies in the left upper quadrant of the human abdomen. It is one of the four cardinal signs of hypersplenism, some reduction in the number of circulating blood cells affecting granulocytes, erythrocytes or platelets in any...

     (enlarged spleen)

See also

  • Symptom
    A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...

  • Stethoscope
    The stethoscope is an acoustic medical device for auscultation, or listening to the internal sounds of an animal body. It is often used to listen to lung and heart sounds. It is also used to listen to intestines and blood flow in arteries and veins...

  • Radiologic sign
    Radiologic sign
    A radiologic sign is an "objective" indication of some medical fact or quality that is detected by a physician during examination of a radiograph .-Examples:*Football sign*Hampton's hump*Omental cake*Pneumatosis intestinalis...

  • neurological sign
    Neurological sign
    A neurological sign is a class of medical signs. Neurological soft signs are minor neurological signs indicating non-specific cerebral dysfunction. Their presence has been documented in cases of schizophrenia.* Focal neurologic signs...

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.