What is the medical term for flat feet?

Medical Terminology for Flat Feet

The medical term for flat feet is "pes planus" or "pes planovalgus." 1, 2, 3

Definition and Characteristics

Pes planus describes a reduction or absence of the medial longitudinal arch (MLA) of the foot, with or without additional deformities of the foot and ankle. 3, 4 The term "pes planovalgus" is used interchangeably and emphasizes the valgus (outward) component often present with the flattened arch. 5

Clinical Context

• The International Working Group on the Diabetic Foot and the American College of Cardiology both use "pes planus" as the standard medical terminology when describing this foot deformity in clinical guidelines. 1

• Pes planus is recognized as a significant foot deformity that can lead to abnormal biomechanical loading, increased pressure points, and elevated risk of foot ulceration, particularly in patients with diabetes or peripheral neuropathy. 1, 6

• The condition affects up to 14% of children and up to 25% of the total population has a deficient medial longitudinal arch in at least one foot. 3

Types of Pes Planus

• Flexible pes planus: A normal arch appears during non-weight-bearing activity or tiptoeing, with flattening occurring only when standing. 5

• Rigid pes planus: The arch remains stiff and collapsed regardless of weight-bearing status. 5