📖 Static demo — read-only snapshot

You’re browsing a static build of the Body IQ knowledge graph, so everything loads with no backend. A few things that need the live server are turned off here:

  • Global search (sidebar) is disabled — it queries the API.
  • The JSON API and the API “Try it” playgroundaren’t included.
  • The data is a snapshot — it refreshes only when the demo is rebuilt, not live from the database.

Everything else — the body map, progression ladders, coverage heatmap, exercise finder, and all anatomy/exercise/source pages — works fully. The full app (live search + API + database) runs from the source on GitHub.

Knee External Rotation

Tibiofemoral Joint • Knee • transverse plane

Draft80%

External rotation of the tibia on the femur. Occurs primarily with the knee flexed. Biceps femoris is the primary external rotator.

Axis: longitudinal

Normal Range of Motion

Axial tibial rotation is not part of the standard AAOS or Norkin & White goniometric examination, so no accepted goniometric normal exists. Kinesiology sources describe roughly 30-40 degrees of tibial external (lateral) rotation available with the knee flexed to about 90 degrees, diminishing to near zero as the knee approaches full extension (screw-home mechanism). Clinically assessed by observing tibial tubercle/foot rotation with the knee flexed at 90 degrees, or instrumented in research settings.

Source: Kinesiology literature (no AAOS/Norkin & White goniometric norm)

Muscles (2)

MuscleRoleNotes
Biceps Femoris — Long HeadPrimaryMoment arm at 30° flexion: 18.5-31.5 mm
Biceps Femoris — Short HeadPrimaryMoment arm at 30° flexion: 14.7-27.9 mm

Exercises (1)

Neuromuscular Exercise (Step-Downs / Single-Leg Balance)

Sources