Edmund M. Kosmahl, PT, EdD



Pronation of the sub-talar joint can compensate for a loss of ankle joint dorsiflexion range of motion. To avoid measurement error (by accidentally including sub-talar pronation), the sub-talar joint must be stabilized in its neutral position. To assess the range of JOINT motion, flex the knee (first illustration). To assess tightness of the gastrocnemius muscle, extend the knee (second illustration).

 ankle dorsiflexion (knee flexed) goniometry picture

Test Position

  • Subject prone
  • Flex knee
  • Stabilize sub-talar in neutral
  • Dorsiflex ankle by pushing through 5th metatarsal head

Normal Range

  • 13o + or - 4.4o (American Academy of Orthopaedic Surgeons)
  • 20o (American Medical Association)
  • 12.6o (mean), 4.4o, (standard deviation) (Boone and Azen)

Goniometer Alignment

  • Axis lateral malleolus
  • Stationary arm aligned with fibular head
  • Moving arm aligned with fifth metatarsal

Normal End Feel

  • Capsular

Assessing Gastrocnemius Tightness (muscle stretch end-feel)

ankle dorsiflexion (knee extended) goniometry picture

copyright 1999 E. Kosmahl