Goniometer ”Myrin”
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In order to assess the results of treatment for limitation of movement, it is necessary
to measure the full range of passive and
active movement before and after treatment.
OB Goniometer “Myrin” makes it possible to measure accurately the movement of
most of the body’s joints. The instrument consists of a small fluid-filled box fixed to a
plate upon which is affected by the earth’s magnetic field, and an inclination needle
which is affected by gravity.
Movement in the horizontal plane round a vertical axis is read form the compass
needle.
The box is fixed to the appropriate part of the body with the help of a Velcro fastening
strap. N.B. that the compass needle can be affected by the influence of iron in the
examination couch or nearby objects.
Therefore the axis of the instrument should be placed as near as possible to the axis
of the joint whose movement is to be measured. This is made possible by the
extension plate.
INSTRUCTIONS FOR USE:
Fix the instrument to the desired place with the strap. For measuring round a vertical
axis, turn the instrument so that the compass needle points to zero. For measuring
round the horizontal axis, turn the instrument so that the inclination needle points to
zero. Perform the movement and read directly from the scale. Check carefully that
the needle moves freely during the whole of the movement. The movement is then in
the correct plane.
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Inclination
needle
Rotable compass housing
Compass needle
Scale 2 x 180o
(Plain figures for
greater legibility)
All components for use of Goniometer “Myrin”
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EXAMPLES OF USE:
Rotation of the cervical spine
The patient sits on a low stool with her head erect. Fix the straps round the head and
over the vertex. Set the compass needle at zero. Support the patient’s back and
shoulders. The patient vigorously rotates her neck to the right and to the left.
Lateral movement of the cervical spine
The instrument is placed at the front or the back. Set the inclination needle at zero.
Bend to the side.
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Flexion and extension of the cervical spine
Fix the strap round the head with the instrument at the side. Set the inclination
needle at zero. Bend the head backwards and forwards.
Rotation of the lumbar spine
The patient sits astride with the arms in front of the chest and the hands gripping the
elbows. The instrument is fixed to the right angled plate which is placed between the
ribs and the innermost forearm. Set the compass needle at zero. Twist the upper part
of the body to the left and then to the right.
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Radio-ulnar deviation at the wrist
The instrument is attaches to the dorsum of the hand. Fix the distal part of the
forearm against a level surface with the hand vertical and away from the edge. Set
the inclination at zero and proceed with radio-ulnar deviation.
Flexion and extension of the wrist joint
Fix the instrument to the ulnar side of the hand with the strap distal to the thumb. Fix
the forearm against a level surface, with he hand away from the edge. Proceed with
flexion and extension.
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Pronation and supination of the forearm
Fix the instrument to the right-angled plate. Hold the elbow at a right angle with the
joint held on the side of the body and the hand forwards. Hold the hand closed and
slightly dorsiflexed. Hold the right angled plate between the proximal interphalangeal
joints at the middle and fore fingers so that the plane of the instrument is the right
angles to the forearm’s long axis. Set the inclination needle a zero and proceed with
pronation and supiration.
Flexion of the elbow
Fix the instrument on the dorsum of the distal part of the forearm. The patient lines
supine with the arm extended. Set the inclination needle at zero and flex the elbow. If
there is limitation of extension draw an imaginary line 90C-90C on the compass
parallel with the forearm. Read the defect from the scale.
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Flexion of the arm
Fix the instrument on the distal part of the arm. The patient lies supine with the upper
arm laterally rotated. Set the inclination needle at zero. Lift the arm forwards and
upwards while maintaining lateral rotation.
Extension of the arm
Same procedure as in last picture, but without lateral rotation. The arm is extended at
the side of the couch.
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