Orbital anatomy, pathology, and changes associated with aging are discussed in detail in BCSC Section 7, Oculofacial Plastic and Orbital Surgery.
Dimensions of the Adult Orbit
Each eye lies within a bony orbit, the volume of which is slightly less than 30 mL. Each orbit is pear shaped; the optic nerve represents the stem. The orbital entrance averages approximately 35 mm in height and 45 mm in width and is widest approximately 1 cm behind the anterior orbital margin. The depth of the orbit, measured from the orbital entrance to the orbital apex, varies from 40 to 45 mm, depending on whether the measurement is made along the lateral wall or the medial wall. Race and sex affect each of these measurements.
Excerpted from BCSC 2020-2021 series: Section 2 - Fundamentals and Principles of Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.