(a) The orbits are paired structures, located on the anterior part of the face and protected by the lids. The skin and subcutaneous tissue have been removed on the left, to expose the orbicularis oculi muscle. The orbicularis oculi surrounds the orbital rim, extends into the lids, and encircle the upper part of the nasolacrimal duct. (b)–(d) Understanding the bony orbit is the first step in successfully choosing and performing an orbital approach. Seven bones form each orbit, and they are arranged to form a four-sided pyramid with a posterior apex and anterior base as shown in red dots (c). This pyramid, however, is not straight, but displays a laterally tilted axis (black outline in (c) and (d)). Although simple, this fact constitutes the basis of the human stereoscopic vision and allows for understanding the location of orbital foramina. (e) In the orbit, all openings are arranged around the base, apex or between the orbital walls. Along the base are the infraorbital (light blue) and supraorbital (dark blue) canals, the zygomatico-orbital foramen (gray), and the zygomaticofacial foramina (black); between the roof and the lateral wall are the superior orbital fissure (purple) and the lacrimal foramen (orange); between the roof and medial wall are the optic (yellow), anterior, and posterior ethmoidal (red) canals; between the lateral wall and floor is the inferior orbital fissure (green), and between the medial wall and the floor is the cranial opening of the nasolacrimal duct (pink). (f) The seven bones forming the orbit have been highlighted in color: frontal (blue), ethmoid (brown), lacrimal (grey), sphenoid (green), zygomatic (pink), palatine (red), and maxilla (yellow). In three of the four orbital walls, these bones are arranged in pairs, with exception of the medial wall.