# goniometer

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Related to goniometry: manual muscle testing

## goniometer

[‚gō·nē′äm·əd·ər]
(electromagnetism)
An instrument for determining the direction of maximum response to a received radio signal, or selecting the direction of maximum radiation of a transmitted radio signal; consists of two fixed perpendicular coils, each attached to one of a pair of loop antennas which are also perpendicular, and a rotatable coil which bears the same space relationship to the coils as the direction of the signal to the antennas.
(engineering)
An instrument used to measure the angles between crystal faces.
An instrument which uses x-ray diffraction to measure the angular positions of the axes of a crystal.
Any instrument for measuring angles.

## Goniometer

(1) In physics, an instrument for measuring the angles between the planes of crystals, and also for measuring the angles of various prisms. Crystals can be distinctively characterized by the angles between their facets. Before the discovery of X-ray structural analysis, the method of measuring crystals with a goniometer was the main means of diagnosing crystalline substances. It was later superseded to a considerable degree by X-ray structural analysis.

Goniometers may be of the contact or reflecting types. The simplest contact goniometer consists of a protractor attached

Figure 1. Single-disk reflecting goniometer: (a) overall view; (b) diagram. C is the collimator, T is the viewing tube, L is the limb, ν is the vernier, and N1 and N2 are normals corresponding to facets a and b. to a ruler; it permits measurement of angles with an accuracy of 0.25°-0.5°. A more precise reflecting goniometer is shown in Figure I.

A crystal attached to a rotating axis is illuminated by a collimated beam of light, and the rays reflected from its facets are observed in sequence by looking into a viewing tube T (a single-circle goniometer). The angles of rotation of the crystal are read from a scale. In more advanced two-circle goniometers (developed by Fedorov, Gol’dshmidt, and Chapskii), the crystal or the viewing tube can be rotated about two axes. The precision of measurement is to within l’ to 10’-20’.

### REFERENCES

Flint, E. E. Prakticheskoe rukovodstvo po geometricheskoi kristallografii, 3rd ed. Moscow, 1956.
Flint. E. E. Nachala kristallografii, 2nd ed. Moscow, 1961.

(2) In anthropology, a goniometer is an instrument for measuring angles of curvature of the spine, the facial angle, the angle of the nose, and so on. A contact goniometer consists of a graduated metal plate in the form of an arc; its ends are joined by a transverse plate with a rotating pointer with a plumb bob attached to its center. The goniometer is attached to dividers (for example, of the sliding type), and the size of the angle being measured is determined by the distance of deflection of the pointer from the vertical.

## goniometer

i. A direction-finding device commonly used in radio location and radio navigation. It has a fixed antenna, and the direction response is varied electrically. Using a method called phase comparison, it senses the angle between a fixed reference point and the direction from which a radio signal is being received. See automatic direction finder.
ii. A motor-driven instrument used with four stationary aerials to a deliver rotating signal field for VOR (very high frequency omnidirectional radio-range).
References in periodicals archive ?
Another goniometry for knee joint is photographic-based goniometry.
Strengths and limitations: First, both the examiners were qualified physiotherapists having more than eight years of clinical and teaching experience and remained involved in teaching goniometry to students which may help in increasing the reliability of UG for measuring neck movements.
Contact angle (CA) was determined by goniometry using static water drop method.
Focusing first on goniometry then on muscle testing, she proceeds by body region from the head through the upper extremity and thoracic and lumbar spine to the lower extremity.
Finger goniometry results for joint movement range were 080 degrees in 4th metacarpophalangeal (MCP) joint in the first case, 0-60 degrees in left 3rd MCP joint in second case and 040 degrees in left 4th MCP joint, 0-80 degrees in proximal interphalangeal joint, 0^10 degrees in 5th MCP joint and 0-90 in proximal interphalangeal joint on third case.
The X-ray powder diffraction patterns of the samples were obtained using a Philips X-ray Diffractometer with vertical goniometry model PW 1050/70 using Cu K[alpha]/Co K[alpha]/Mo Ka[alpha] radiation with nickel/iron/tantalum filters.
This test focused on the assessment of motor domains of primitive reflexes, head control, sitting without support, passive and active tone, popliteal angle, and adductor angle hip through the use of goniometry.
Materials used to measure the effects of dorsiflexion resisted walking included goniometry, surface electromyography (sEMG), and GAITRite technology (2), respectively.
The procedures mostly used in clinics and research include goniometry (3,26) and visual estimation (27).
Surface energies of supported lipid bilayers, optionally covered by PEG, were quantified with contact angle goniometry and AFM.
Efficacy assessments will include measuring finger goniometry and range of motion of the treated joints on days 1, 8, 30, and 60, following the first cycle of two injections.
profilometry, SEM, goniometry, and drug dissolution.

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