Medical timeline glossary
Short version: 15 terms used on this site, defined for a physician reading a timeline rather than building software. Each one links back from the pages where it appears.
Limits: Tool facts come from each vendor's own website, read 2026-11-12; we have not used those products. The case on this site is synthetic, with no real patient.
Timeline formats and parts
- Time axis
- The horizontal scale of dates. On a true-date axis, distance equals time, so a 4-month gap is wider than a 1-week gap. An evenly spaced axis puts events at equal steps and hides gaps.
- Event marker
- A single mark (dot, square, diamond) for something that happened on 1 date: a visit, a scan, a procedure. Shapes let markers be told apart without color.
- Swimlane
- A horizontal row for 1 category (visits, imaging, a provider) on a shared time axis. Lanes show what happened in parallel. See swimlanes.
- Duration bar
- A bar from a start date to an end date: a medication, an admission, a work restriction, a therapy course. Its length shows how long, and overlapping bars show what ran together.
- Density strip
- A row of columns counting events or pages per week or month. It shows where a file is thick or thin, which helps plan reading and spot missing periods.
- Small multiples
- Several small charts with the same axis stacked together, such as a pain score panel and a lab panel under the event lanes, so changes line up in time.
- Gantt chart
- A project-planning chart of tasks as bars on a time axis. Medication and work-status lanes borrow its form, and project tools such as Lucen Timeline can draw one.
- Key date
- The date the case turns on: an injury, an admission, a surgery, an alleged error. Drawn as a line so the reader sees before and after.
Record terms
- Chronology
- A dated table of events from the records, 1 row per event, each with its source page. A timeline is a picture of a chronology; most AI tools build the chronology and show it as a list.
- Page cite
- The page number in the record file where a fact appears. Every mark on a review timeline should lead to 1.
- Undated record
- A page with no usable date, such as a handwritten form or a fax with the date cut off. A timeline can't place it, so it must list it separately.
- Gap in care
- A stretch with no clinical contact longer than you'd expect for the condition. On a true-date axis it shows as empty space. Whether a gap matters is a clinical judgment, not something the chart decides.
Privacy and context
- PHI
- Protected health information under HIPAA: health data that can identify a patient. Dates of service count, which is why a timeline of a real case is PHI.
- BAA
- Business Associate Agreement: the HIPAA contract a vendor signs before it may handle PHI for you. No BAA, no real records in that tool.
- IME
- Independent medical examination: an exam and report by a physician who isn't treating the patient, usually for a claim. IME files are often long, which is where timelines help most.