Cephline is a cephalometric tracing app for orthodontic students and practitioners.

Open a lateral cephalogram, place 24 landmarks, and read 28 measurements across four classical analyses: Steiner, Downs, Wits and Tweed.

PLACE THE POINT WHERE YOU MEANT TO
Landmark precision is what this app is built for. A magnifier loupe sits above the point you are placing, so your fingertip never covers the anatomy you are aiming at. One finger places a landmark and two fingers move the image, with no mode to switch. Pinch to zoom and the drag gets finer as you go in. Nudge arrows move a landmark by exactly one image pixel. Tap anywhere to reposition the point you are working on. Undo and redo at every step.

Landmarks are stored in image coordinates, not screen coordinates, so your readings do not change when you change phone or screen size.

CALIBRATION YOU CANNOT SKIP
Millimetre readings are only as good as the scale behind them. Cephline derives the scale from a reference of known length that you mark on the film yourself, and rejects a reference that cannot be right. There is no field for typing a scale in by hand, and no millimetre reading without a calibration. Angles do not depend on scale and are always available.

WHAT IT COMPUTES
• Steiner: 14 measurements
• Downs: 10 measurements
• Wits appraisal, with the published norm for each sex
• Tweed triangle: FMA, IMPA and FMIA

Every reading is shown with its published norm and the distance from it. Construction lines draw the exact geometry each number was read from, so you can see what moved a value. Each measurement carries a short note on what it describes and on the placement slip that most often distorts it, including how far a one millimetre slip actually moves that number.

A glossary defines every landmark, and you can open it from the placement screen while you work.

YOUR WORK STAYS PUT
Cephline saves as you go, so a closed app or a phone call does not cost you a tracing. Save a case as a .cephline file, with the film inside it, and open it again later on the phone or in a laptop browser at cephline.com. Share the readings as text.

NOTHING LEAVES YOUR PHONE
• No account, no login, no trial
• No ads and no in-app purchases
• No analytics and no tracking
• Works entirely offline
• Asks for no permissions at all

The film and every landmark stay on your device. Cephline has no server to send anything to.

FREE
All four analyses and all 28 measurements. No paywall and nothing held back.

Cephline computes measurements and shows them against published norms. It does not recommend or plan anything. Interpretation remains yours.