Edmund M. Kosmahl, PT, EdD

Department of Physical Therapy - University of Scranton



Knee flexion should be measured with the subject supine. This position allows assessment of the joint range of motion without interference from tightness in the rectus femoris muscle.  If the examiner wishes to assess length of the rectus femoris, have the patient lie prone (see 2nd illustration).

 knee flexion supine goniometry picture

Test Position

  • Subject supine
  • Allow hip to flex
  • Flex knee

Normal Range

  • 141o + or - 5.3o (American Academy of Orthopaedic Surgeons)
  • 150o (American Medical Association)
  • 142.5o (mean), 5.4o, (standard deviation) (Boone and Azen)

Goniometer Alignment

  • Axis lateral epicondyle of femur
  • Stationary arm aligned with greater trochanter
  • Moving arm aligned with lateral malleolus

Normal End Feel

  • Soft tissue approximation

Prone Position (Rectus Femoris Limiting)

knee flexion prone goniometry picture

copyright 1999 E. Kosmahl