11: Orbit

The eyeball is the essential organ of sight, and is also involved in non-verbal communication. It is protected by the bony orbit, which also contains the extraocular muscles and the lacrimal gland. Although the eyeball itself is an uncommon site of malignancy, it can be impacted on by several benign conditions and contains several structures that are sensitive to radiotherapy. For these reasons, anatomy of the eyeball and orbit is essential for the practice of radiation oncology.