Feiss Line Test

The Feiss line test is used to assess the height of the medial arch, using the navicular position, it’s a valid clinical measure of the medial longitudinal arch. The Feiss Line test is easy to conduct and requires no additional measuring devices apart from a pen and goniometer.

How do you perform the Feiss Line Test?

With the patient non–weight-bearing, the clinician marks the apex of the medial malleolus and the plantar aspect of the first MTP joint, and a line is drawn between the two points the so called (Feiss Line). The navicular is palpated on the medial aspect of the foot, and an assessment is made of the position of the navicular relative to the imaginary Feiss line. The patient is then asked to stand with their feet approximately 3–6 inches apart.

See Also: Navicular Drop Test

In weight-bearing, the navicular normally lies on or very close to the Feiss line.

The degree of flatfoot deformity is defined as following:

• If the navicular falls one-third of the distance to the floor, it represents a first-degree flatfoot;
• if it falls two thirds of the distance, it represents a second-degree flatfoot;
• if it rests on the floor, it represents a third-degree flatfoot.

No diagnostic accuracy studies have been performed to determine the sensitivity and specificity of Feiss line test.

Modified Feiss Line Test

Modified Feiss Line Test requires that the navicular in a neutral foot is positioned upon the modified Feiss Line. By changing the position of one end of the Feiss Line from the original position on the medial malleolus to a parallel shifted point on the Achilles tendon and retaining the original point from the Feiss Line on the first metatarsal head, a resultant lowering of the Feiss Line occurs. Thus, the navicular is placed on the line in the neutral foot.

This makes the definition of pes rectus, pes planus and pes cavus easier for clinicians, as the navicular is placed below and above the new Feiss line in low or high arched individuals, respectively. Before the new line can be recommended to clinicians and applied in research and clinical work it has to be tested for reliability and validity.

References & More

1. Dutton’s Orthopaedic Examination, Evaluation, And Intervention 3rd Edition.
2. PalmerML, Epler M: Clinical Assessment Procedures in Physical Therapy. Philadelphia, PA: JB Lippincott, 1990.
3. Spörndly-Nees S, Dåsberg B, Nielsen RO, Boesen MI, Langberg H. The navicular position test – a reliable measure of the navicular bone position during rest and loading. Int J Sports Phys Ther. 2011 Sep;6(3):199-205. PMID: 21904698; PMCID: PMC3163999. Pubmed
4. Spörndly-Nees S, Dåsberg B, Nielsen RO, Boesen MI, Langberg H. The navicular position test – a reliable measure of the navicular bone position during rest and loading. Int J Sports Phys Ther. 2011 Sep;6(3):199-205. PMID: 21904698; PMCID: PMC3163999. Pubmed