Understanding the Navicular Drop Test (or Staheli's Arch Index) Assessment
To quantify the change in height of the **medial longitudinal arch** from non-weight bearing to full weight bearing (assessing flexible flatfoot).
Watch How It's Done
How do I start?
Patient is sitting with the foot resting comfortably (non-weight bearing).
What happens?
The examiner measures the vertical distance from the **navicular tuberosity** to the floor. The patient is then instructed to stand, and the measurement is repeated with **full weight bearing**.
In Plain English
What Does a Positive Result Mean?
A drop of **more than 10-15mm** in the navicular tuberosity height is considered excessive pronation and indicative of a flexible flatfoot.
Helpful Tip:
The difference between the two measurements provides a reproducible measure of arch collapse.
Safety First
This guide is to help you understand what happens in a clinic. Do not try to diagnose yourself. If you have severe pain, swelling, or cannot put weight on your leg, please visit an urgent care center or your doctor immediately.
Other Foot Tests
Coleman Block Test
To assess the **flexibility of a hindfoot varus deformity** and determine if it is fixed (bony) or flexible (soft tissue) in a patient with a **Cavus Foot (High Arch)**.
External Rotation Stress Test (Syndesmosis Ligament Test)
To assess the integrity of the **Distal Tibiofibular Syndesmosis** (high ankle sprain ligaments) by applying a rotational stress.
Feiss Line Test (or Feiss Line Grading)
To clinically assess and grade the degree of **longitudinal arch collapse (Pes Planus or Flat Foot)**.
Toe Spread Test
To assess the **strength and endurance of the intrinsic foot muscles** (IFMs), which are essential for arch stabilization and dynamic balance.