Biceps Crease Interval

Published August 30, 2026 Read time 1 min read Readers 18
Biceps Crease Interval

What is the "Biceps Crease Interval" used for?

  • Distal biceps tendon rupture

How to perform the "Biceps Crease Interval"?

  • The patient is seated. Starting with the patient’s unaffected arm in flexion, the examiner extends the patient’s elbow fully. 
  • A line is drawn across the flexion crease in the antecubital fossa. 
  • The examiner then lightly strokes the contour of the distal biceps back and forth along a central longitudinal line until the examiner can identify the point at which the distal biceps begins to turn most sharply toward the antecubital fossa and marks a transverse line at the distal cusp of the biceps. 
  • The examiner then measures the distance between the two transverse lines
  • The distance is recorded as the biceps crease interval (BCI) and both arms are compared.

What is the positive result?

  • The BCI is normally 4.8 cm ± 0.6 cm for both the dominant and non-dominant arm. 
  • If the BCI is greater than 6.0 cm or the biceps crease ratio between the two arms is greater than 1.2, the test is positive for a distal biceps tendon rupture.