Abstract: The clinical data of 16 cases of habit tic deformity in our hospital were analyzed retrospectively. Of 16 patients, 10 were males and 6 were females. The onset age of patients ranged from 4 to 31 years old, with average of 15.56±10.03 years old. There were a total of 38 nails were involved, including 30 thumbnails, 4 ring finger nails, 2 index finger nails and 2 middle finger nails. These involved nails were symmetrically distributed in each patient. Most of them are thumbnails. The characteristic nail changes included concavity and parallel transverse ridging of nails.

Key words: habit tic deformity, thumbnail