Orbit
Compartments
4 compartments of the orbit:
1. ocular (AKA globe, AKA bulbar)
3. intraconal
4. extraconal
A good understanding of the anatomical details is required to ensure optimal results during surgery of the orbit. Several indications for orbital surgery require biopsy, resection, or reconstructive procedures. The intricate relationships between the orbital septum and adjacent structures of the upper orbit can cause difficulties in interpreting the surgical anatomy of this region.
The orbit is the cavity or socket of the skull in which the eye and its appendages are situated. “Orbit” can refer to the bony socket, or it can also be used to imply the contents. In the adult human, the volume of the orbit is 30 mL, of which the eye occupies 6.5 mL.
The walls of the orbit are formed by seven bones: frontal bone, zygomatic bone, sphenoid bone, lacrimal, ethmoid, and palatine bones and the maxilla. The upper border of the orbital opening is formed by the frontal bone. The lateral border of the orbital opening is formed by the frontal process of the zygomatic bone, except for the upper part, which is formed by the zygomatic process of the frontal bone. The lower margin of the orbital opening is formed laterally by the zygomatic bone and medially by the maxilla. The upper part of the medial border is formed by the frontal bone and the lower part is formed by the frontal process of the maxilla. The medial part of the upper border contains the frontal sinus.