THE ORBIT

THE ORBIT   
The orbit is a cone-shaped vault . At its apex are three orifices through
which pass the nerves, arteries, and veins supplying
the eye.

Clues that may indicate disease
of the orbit :

A. Proptosis (exophthalmos)—forward bulging
of the eye.
B. Enophthalmos—sunken eye.

C. Swollen lids (sometimes totally shut);
redness and engorgement of conjunctival
vessels; clear fluid under conjunctiva (chemosis).

D. Loss of eye movement (ophthalmoplegia)
due to involvement of cranial nerves III, IV,
and VI or local damage to extraocular muscles.
Orbital cellulitis causes the lids to be swollen
shut (Fig. 154). The globe may not move (ophthalmoplegia)
and there is chemosis, fever,
adenopathy, and exophthalmos. It is most
often due to sinusitis, but also occurs with
tooth, facial or lid infections.
An orbital septum connecting the lid tarsal
plates to the orbital rim  acts as
a barrier protecting the orbit from lid infections.
Beware of the rare breakthrough.
Orbital cellulitis can spread to the cavernous
sinus through the superior and inferior ophthalmic
veins that drain the orbit and part of
the face. This could cause thrombosis and
death. Rx: hospitalize the patient and treat
with systemic antibiotics.
Orbital fat may migrate under the conjunctiva or herniate through the septum
under the skin. This is only a cosmetic
problem.