Canalis sinuosus: a rare anatomical variation

The infraorbital canal issues a small branch on its lateral face close to its midpoint to allow passage of the anterior superior alveolar nerve. This small canal, sometimes called the canalis sinuosus, runs forward and downward to the inferior wall of the orbit, lateral to the infraorbital canal and medially bent to the anterior wall of the maxillary sinus, passing below the infraorbital foramen. Anatomical variations in the maxilla are rarely described in the literature and, in most cases, are related to the nasopalatine canal. This article describes a rare anatomical variation of the presence of a bilateral accessory canal extending from the nasal cavity lateral wall to an accessory foramen located on the hard palate, adjacent to the maxillary lateral incisor observed in cone beam computed tomography (CBCT) images. This case is an anatomical variation of the anterior superior alveolar nerve (canalis sinuosus). Identification of individual anatomical variations, especially on CBCT, may help the surgeon to avoid injuries to nerves during implant placement.