Feiss Line is an ankle examination procedure that tests for pes planus, flatfoot, fallen medial longitundinal arch.
Patient should be awake and cooperative in a Feiss Line test.
- Patient should be standing with weight distributed evenly.
- The examiner uses a marker to mark the inferior apex of medial malleolus and medial surface of the base of the base of the 1st metatarsal.
- The examiner draws a line connecting the two points.
- The examiner locates the the navicular tuberosity and marks it.
Positive Feiss Line
There is a positive Feiss Line test when there is navicular tuberosity is below line. This could indicate the presence of pes planus, flatfoot or fallen medial longitudinal arch.
There are different grades of flatfoot:
Grade 1: Navicular tuberosity falls 1/3 of distance to floor.
Grade 2: Navicular tuberosity falls 2/3 of distance to floor.
Grade 3: Navicular tuberosity touching the floor.