Anatomic locations:
(1) cephalad aspect of medial malleolus
(2) plantar aspect of the medial first metatarsophalangeal joint
(3) navicular tuberosity on the medial aspect of the foot
The first set of measurements is performed when the foot is not weight bearing. Normally the navicular tuberosity is in the line connecting the medial malleoulus and first metatarsophalangeal joint.
The second set of measurements is performed with the foot weight-bearing while the feet are about 8 to 15 cm apart. The navicular tuberosity may be slightly below the line connecting the medial malleolus and first metatarsophalangeal joint.
where:
• A photograph of the marks may be helpful to document the findings, especially if they will be tracked over time.
Measurements during weight bearing:
(1) vertical distance from line to floor, going through the navicular tuberosity
(2) vertical distance from the navicular tuberosity to the floor
ratio of distances =
= (distance from navicular tuberosity to floor) / (distance from line to floor) * 100%
|
Ratio
|
Interpretation
|
|
> 90%
|
normal
|
|
66%
|
first degree flatfoot
|
|
33%
|
second degree flatfoot
|
|
< 5%
|
third degree flatfoot
|
Limitations:
• Accurate designation of the anatomic locations is important if the findings are to be reproducible.
