The orbital surface is smooth and triangular, and forms the greater part of the floor of the orbit.
It is bounded medially by an irregular margin which in front presents a notch, the lacrimal notch; behind this notch the margin articulates with the lacrimal, the lamina papyracea of the ethmoid and the orbital process of the palatine.
It is bounded behind by a smooth rounded edge which forms the anterior margin of the inferior orbital fissure, and sometimes articulates at its lateral extremity with the orbital surface of the great wing of the sphenoid.
It is limited in front by part of the circumference of the orbit, which is continuous medially with the frontal process, and laterally with the zyogmatic process. Near the middle of the posterior part of the orbital surface is the infraorbital groove, for the passage of the infraorbital vessels and nerve. The groove begins at the middle of the posterior border, where it is continuous with that near the upper edge of the infratemporal surface, and, passing forward, ends in a canal, which subdivides into two branches. One of the canals, the infraorbital canal, opens just below the margin of the orbit; the other, which is smaller, runs downward in the substance of the anterior wall of the maxillary sinus, and transmits the anterior superior alveolar vessels and nerve to the front teeth of the maxilla. From the back part of the infraorbital canal, a second small canal is sometimes given off; it runs downward in the lateral wall of the sinus, and conveys the middle alveolar nerve to the premolar teeth.
At the medial and forepart of the orbital surface just lateral to the lacrimal groove, is a depression, which gives origin to the Obliquus oculi inferior.