The eyeball is safely lodged in a bony socket called the orbit on the two sides of the nose. The four-sided orbital cavity is pyramidal in shape with an open base in front and an apex on the back. The four walls of the orbit converge posteriorly to reach the apex on their back formed by the optic foramen. The four walls are called the roof, floor, and medial and lateral walls. The lateral wall, which has a protective function, is the strongest. The medial wall is the thinnest and contains the ethmoidal sinuses with ethmoid air cells. There are three sinuses—anterior, middle, and posterior—on each side. They are liable to fracture with severe contusion injuries of the orbit, in which case air may enter the orbit and periorbital tissues, causing periorbital crepitus. Nasal bleeding may occur if the patient blows his or her nose.
KeywordsFour-walled orbital cavity Bony socket for eyeballs Pyramidal shape Apex and base of orbit Paranasal sinuses Frontal ethmoidal Maxillary Roof Floor Lateral and medial walls of orbit Mucocele Proptosis
- Parsons’ Diseases of the Eye, edn 16. Revised by Miller SJH. London: Churchill Livingstone; 1979. pp. 1–14; 545–60Google Scholar
- Riordon-Eva P, Cunningham E (2011) Vaughan and Asbury’s general ophthalmology, edn 18. McGraw Hill, New York, pp 1–26Google Scholar
- Trevor-Roper PD (1974) The eye and its disorders. Blackwell Scientific Publications, London. pp 26–44, 323–34Google Scholar
- Wolff’s E (1976) Anatomy of the eye and orbit, edn 7. Revised by Warwick R. London: HK Lewis; 1976; pp. 1–29; 30–180DGoogle Scholar