High‐frequency ultrasonography index in evaluation of pincer nail

Background: The measurements of width index, height index, and curvature index were used for assessment of the curvature severity. Nevertheless, both sides of the nail root are buried subcutaneously, impossibility in measuring the width index correctly. Materials and Methods: We developed a technique to measure the index under high‐frequency ultrasonography (HF‐USG). Results: There was good agreement between the HF‐USG index and the result examined after surgery. Conclusion: The observation on HF‐USG helps to distinguish between ingrown nail and pincer nail. The HF‐USG index will be useful in the examination and measurement of nail roots buried subcutaneously or nail penetration under the hypertrophic lateral nail fold, and comparing the effectiveness among treatments for pincer nail objectively.