Pocket Goniometer

0°

Sensors off

Hands-free hold

Tap dial to holdThe whole dial works as one big Hold / Release button. Auto-hold at end rangeHolds the reading once it stays steady for 1 second at the end of a movement, with a flash and a beep (ringer on). Re-arms when you return to the start or tap Zero.

How to measure

Track one segment. Strap or hold the phone on the moving segment, tap Zero at the start position, move through range, then Hold or Save at end range. The app learns the plane of motion and ignores the phone rolling on the limb.
Two-segment. Zero with the phone on the proximal segment, then place it the same way on the distal segment. The reading is the angle between them. Best for elbow and knee extension.
Zero, Hold and Save wait for stillness. If a button says Wait…, keep the phone still for a moment. The app then averages the last third of a second, so tapping the screen doesn't change the number.
Off plane warning. If it shows, the phone has rolled or the limb left the plane of motion. Reposition and re-zero.
Horizontal plane. Track and 2-segment read tilt against gravity, so they need motion in a vertical plane. For motion along a flat surface or around a vertical axis (supine hip abduction, shoulder horizontal abduction, seated trunk or neck rotation), use Horizontal, which reads the gyroscope heading. Zero right before each trial and keep the phone's tilt steady, because gyro heading can drift slightly over a minute or two.
Landscape only. The app always shows sideways. Hold the phone in landscape to read it. If the phone is upright or rotation-locked, the app turns itself sideways.
Check your phone once. Zero it flat on a table, then stand it on its long edge against a box. It should read 90° (±1°).
For re-tests, use the same position, the same phone placement and the same method each visit. Re-zero before every trial.
Normal is AAOS adult ROM. Functional is the motion most daily activities need: shoulder (Namdari 2012), elbow and forearm (Morrey 1981), wrist (Ryu 1991), hip (Johnston & Smidt 1970), knee (Rowe 2000), hip extension and ankle (gait). A dash means no well-established value. Values vary by study, age and task. This is a clinical aid, not a certified medical device.

Take or choose photo

For accuracy: mark landmarks with small stickers, stand about 2 m back and zoom 2×, and hold the camera level at joint height, square to the plane of motion.

Take a photo with the joint at end range, then tap three landmarks. Photos stay on this phone and are not saved to your camera roll.

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New photo

Encounter 1

No readings in this encounter yet. Everything you save from Sensor or Photo goes here until you tap New encounter.

Encounters stay on this phone only (the last 40 are kept). Enter no patient names or identifiers.

Hands-free hold

Encounter 1

Earlier encounters