Figure-of-Eight Method for Ankle Measurement

The Figure-of-Eight Method is used to assess ankle size and swelling (edema)¹. It is widely applied in clinical practice due to its advantages: it is reproducible, captures swelling at multiple points around the ankle, requires only a tape measure and marker, and is time-efficient, cost-effective, and easy to perform¹².

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Equipment

• A plastic tape measure (¼ inch wide)

• A skin-safe marker³

Patient Position

• The patient lies in a long sitting position on a bench with the foot resting over the edge.

• The knee can be slightly flexed with a pillow for support.

• The ankle should be kept in neutral dorsiflexion¹.

Therapist Position

• The therapist stands at the foot of the bench¹.

Procedure

Mark the following anatomical landmarks with a marker:

1. Midpoint on the anterior ankle between the tibialis anterior tendon and lateral malleolus

2. Tuberosity of the navicular

3. Base of the fifth metatarsal

4. Inferior tip of the medial malleolus¹

Step-by-step execution:

• Place the zero point of the tape at the anterior ankle mark.

• Pull the tape medially across the navicular.

• Pass it inferolaterally across the medial arch to the base of the fifth metatarsal.

• Draw it superomedially across the tarsals, over the medial malleolus, and posterolaterally around the Achilles tendon.

• Pass it across the distal lateral malleolus and return to the zero point.

• Record the measurement¹.

⚠️ Ensure the tape does not indent the soft tissue¹.

https://www.youtube.com/watch?v=FJRuACV9fh0

Evidence

• Laboratory findings: Intra- and interrater reliability ICC = 0.98–0.99 for both asymptomatic and swollen ankles; strong correlation with water displacement volumetry (r > 0.88)¹.

• Clinical findings: Very high intra- and interrater reliability (ICC ≥ 0.99) with a standard error of measurement (SEM) of ±0.2 cm¹.

• Compared to foot volumetry, the Figure-of-Eight Method demonstrated excellent validity and reliability¹⁵.

Conclusion

The Figure-of-Eight Method is a reliable and valid tool for assessing ankle swelling. With its simplicity, reproducibility, and minimal equipment needs, it is highly suitable for clinical use, both in routine practice and research.

Sources:

1. Watson C.P, Boland R.A, Refshauge K.M. Measurement reliability of swelling in the acute ankle sprain. The Foot & Ankle Journal. 2008:1(12):4.

2. Esterson P.S. Measurement of ankle joint swelling using a figure of 8. Journal of Orthopaedic & Sports Physical Therapy. 1979:1(1):51-52.

3. Tatro-Adams D, McGann S.F, Carbone W. Reliability of the figure-of-eight method of ankle measurement. Journal of Orthopaedic Sports and Physical Therapy. 1995:22:161-163.

4. Figure-8 Measurement (CR).hentet fra : https://www.youtube.com/watch?v=cG-A3PbS5ow

5. Mawdsley R, Hoy D, Erwin P. Criterion-related validity of the figure-of-eight method of measuring ankle edema. Journal of Orthopaedic Sports and Physical Therapy. 2000:30:148 –153.