Anatomy for ophthalmic anaesthesia.

Study of the anatomy of the orbit, its contents and surrounding structures allows the anaesthetist to understand how to insert needles within the orbit. Local anaesthetics may thereby be deposited in sites where they may spread to block sensory and motor nerves to provide anaesthesia and akinesia, without damaging the globe, blood vessels, lacrimal apparatus, muscles or the optic nerve and its coverings. Traditional techniques of dissection fail to show structural relationships as they exist in the living. Newer methods of cadaveric orbital fixing and thick section examination, and CT and MRI scanning techniques have added to the ease of understanding the system of connective tissue septa supporting the globe within the orbit. These tissues allow extensive mobility and also divide the orbit into functional adipose compartments allowing distribution of injected local anaesthetic solutions to gain access to neural tissue. In this review, the anatomy is described with reference to relevant drawings and diagrams and with the economical use of descriptive text. Excellent detailed texts are available for further study.