The difference between an internal bunion and a bunion is very significant. In actual clinical work, bunions account for the vast majority of overall thumb deformities, and internal bunions are extremely rare. An ectropion is a deflection of the thumb outward relative to the angle of the entire metatarsal body, producing an external deformity of the thumb, whereas an inversion is the opposite, a deformity in which the thumb is turned medially. In clinical practice, the vast majority of patients have an ectropion deformity, and the bunion deformity arises only from a congenital developmental abnormality. Ectropion, on the other hand, can be caused by adverse triggers of daily life in addition to congenital developmental abnormalities.