Medical Terminology for Fallen Arch with Pronation
The medical term for a fallen arch associated with pronation is "pes planus" or "pes planovalgus" (flatfoot). 1, 2
Terminology and Definition
- Pes planus describes a reduction or complete absence of the medial longitudinal arch (MLA) of the foot 2
- Pes planovalgus is the more specific term when the condition includes both the flattened arch and the valgus (pronated) positioning of the hindfoot 1
- The condition is characterized by collapse of the midfoot arch, particularly during weight-bearing activities 3
Clinical Classification
The condition is further categorized into two distinct types that have important clinical implications:
Flexible Pes Planus
- Normal arch appears during non-weight-bearing activity or when standing on tiptoes, but flattens with full weight bearing 1
- This represents the most common presentation and can be part of normal developmental variation in children 2
- Up to 25% of the total adult population has a deficient MLA in at least one foot 2
Rigid Pes Planus
- The arch remains stiff and collapsed regardless of weight-bearing status 1
- Patients with rigid pes planus require subspecialist referral as this indicates more serious underlying pathology 1
Associated Biomechanical Changes
- Compensatory pronation associated with pes planus is one of the most common lower extremity disorders currently encountered in clinical practice 4
- The flattened arch affects normal biomechanics throughout the entire lower limb, potentially causing unbalanced and functionally unstable conditions 4
- The condition impacts weight bearing, force dissipation, and normal gait patterns 4
Common Pitfall
A critical distinction must be made between flexible and rigid pes planus during initial evaluation, as rigid pes planus requires immediate subspecialist referral rather than conservative management 1. The simple test of observing arch formation during non-weight-bearing or toe-standing differentiates these two conditions.