Figure of Eight Method of Measuring Ankle Joint Swelling


The purpose of this assessment technique is to evaluate ankle size and ankle joint swelling.


A retractable one-quarter inch wide retractable plastic tape measure can be used[1]. The assessment technique can be carried out with the patient long sitting with both feet extending from the end of a plinth. The knee may be slightly flexed over a bolster to allow for ease of measurement if needed. The ankle should ultimately be maintained in a position of neutral dorsiflexion.

Once the patient has assumed their position on the plinth the measuring tape is placed midway between the tendon of the tibialis anterior and the lateral malleolus. The tape is pulled medially toward the distal side of the tuberosity of the navicular. The tape can now be drawn across the instep ending proximal to the base of the 5th metatarsal. The tape is then pulled across the tibialis anterior tendon and continues around the ankle joint just distal to the medial malleolus. From the medial malleolus the tape can be drawn across the Achilles tendon circling around the ankle ending just distal to the lateral malleolus. From the lateral malleolus the measurement can be ended where the measurement was begun1.


The intraclass correlation coefficient for interrater reliability is 0.99 and mean interrater reliability is 0.99 1. The figure of eight measurement has also demonstrated criterion-related validity when compared to foot volumetry[2]. The figure of eight method of measuring ankle joint swelling can be considered both valid and reliable.



  1. Tatro-Adams D, McGann SF, Carbone W. Reliability of the figure-of-eight method of ankle measurement. / Orthop Sports Phys Ther. 1995;22:161-163.
  2. Mawdsley R, Hoy D, Erwin P. Criterion-related validity of the figure-of-eight method of measuring ankle edema. J Orthop Sports Phys Ther. 2000;30:148 –153.