Removal of third molars is one of the most common operations performed in oral surgery. A well recognized serious complication of mandibular third molar extraction is injury to the inferior alveolar nerve (IAN). We describe a case of an unusual nerve passage discovered after the extraction of a completely erupted third molar. The likelihood of direct damage to the IAN can be predicted with more specific information obtained by the use of a preoperative computerized tomography scan when conventional radiography does not clearly show the nerve canal.