The thermometer must be held under the tongue

Relates generally to apparatus for electronically measuring the temperature of a living body, and more particularly, to a thermometer that exhibits enhanced conformity to the anatomy of a human being, especially in and around the mouth.

From the patient’s viewpoint, this form of thermometer is awkward because the thermometer must be held under the tongue. As viewed from the side, the rod of the thermometer should be inclined upwardly at an angle of about 30 degrees from the horizontal in order to operate effectively and accurately. Many patients have a natural tendency to bite down on the thermometer with their teeth. The upper teeth of most humans extend forward of the lower teeth with an overbite. When the thermometer is inserted in the mouth, it ordinarily rests on or close to the lower teeth. Thus, when a patient bites down on the thermometer, the lower teeth act as a fulcrum to apply rotational forces on the thermometer. Such rotational forces tend to dislodge the thermometer from under the tongue, usually up to and against the palate. This requires that the thermometer be relocated back under the tongue. To avoid this problem, some patients extend their lower jaw so that the lower teeth are forward of the upper teeth. However, this extension of the lower jaw is unnatural and uncomfortable.

Such electronic thermometers with digital displays offer improved convenience and accuracy compared to reading the linear scale of the basic mercury thermometer. However, these linear electronic thermometers exacerbate the problems of keeping the tip of the thermometer under the tongue due to the increased moments of inertia presented by the additional weight and mass of the enlarged housing at the opposite end of the thermometer. This problem can be particularly acute in. patients unused to, or uncooperative in, having their temperature taken, such as children or the elderly.

Electronic thermometers have been introduced which emulate the linear structure of the basic mercury thermometer. A numerical display is usually disposed on electronic thermometers to assist in reading the measured temperature. Electronic thermometers also avoid any potential mercury exposure issues associated with a mercury thermometer. These electronic thermometers have a temperature sensing tip at one end for insertion under the tongue, an intermediate linear shaft and an enlarged body or housing at the end opposite from the sensing tip. The enlarged housing contains electronics for translating a temperature signal from the sensing tip into the currently measured temperature. Typically, the enlarged housing also contains a display, such as of the liquid crystal display (LCD) type, for displaying the measured temperature. The enlarged housing also contains a source of electrical power, such as a miniature battery.

Such electronic thermometers with digital displays offer improved convenience and accuracy compared to reading the linear scale of the basic mercury thermometer. However, these linear electronic thermometers exacerbate the problems of keeping the tip of the thermometer under the tongue due to the increased moments of inertia presented by the additional weight and mass of the enlarged housing at the opposite end of the thermometer. This problem can be particularly acute in. patients unused to, or uncooperative in, having their temperature taken, such as children or the elderly.

Preferred thermometers feature a probe design that prevents the temperature-sensing tip from accidentally sliding off the hot spot found under the tongue of a patient. The preferred thermometer exhibit enhanced conformity to the anatomy of the patient, particularly in and around the mouth.

The probe may be flexible so that it can be bent into a desired non-linear configuration to best fit the mouth of the patient. Such flexible probes may have an internal stiffener, so that the probe will hold the shape to which it is bent. The internal stiffener may be, for example, a strand of copper wire, a polymer of good ductility and low elasticity, or a series of flexible joints. The internal stiffener may be covered by a softer plastic overmold. Alternatively, these probes can be made of a polymer which is flexible and of low elasticity so as to be poseable into a desired shape and remain shaped without requiring a separate internal stiffener.

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