Herniation of Fat from the Infraorbital Canal into the Maxillary Sinus: A Cadaveric Case Report.

The infraorbital canal serves as a conduit for the infraorbital nerve. The canal travels anteriorly beneath the globe where it emerges onto the face at the infraorbital foramen. Variations in the morphology of the infraorbital canal have been reported and classified based on their relationship with the maxillary sinus. Similarly to the other orbital fat compartments, fat in the infraorbital canal serves as protection to the structures it surrounds. Generally, the orbital fat compartments do not undergo hypertrophy without a pathological etiology, therefore, it has been hypothesized that herniations of orbital fat are a result of age-related bony changes in the orbit. The inferior orbital rim, in particular, acts to support structures of the orbit including the fat compartments, ligaments, and muscles. The most commonly reported herniations are those of the infraorbital fat pads, which either prolapse into the inferior orbital fissure or move anteriorly to give patients the appearance of a bulging lower eyelid. Additionally, there are reports of traumatic injuries that result in herniation of the buccal fat pad into the maxillary sinus. Herein, we report a rare case of a herniation of the infraorbital canal fat into the maxillary sinus and review the salient literature.