Bones forming the orbit are:
Orbital Margins are :
1. Superior margin; frontal bone
2. Inferior margin; maxilla and zygomatic
3. Medial margin; frontal, lacrimal and maxilla
4. Lateral margin; zygomatic and frontal
The orbital cavity contains walls:
The Roof formed by the frontal and sphenoid
The Lateral Wall; zygomatic & sphenoid
The Floor; maxilla, zygomatic & palatine
The Medial Wall; maxilla, lacrimal, ethmoid &
Five orbital openings :
Optic Foramen (C.N II & ophthalmic artery)
Superior Orbital Fissure (C.N III, C.N IV, C.N
VI, ophthalmic vein & sympathetic fibers)
Inferior Orbital Fissure (Maxillary nerve,
infraorbital vessels and ascending branches
from sphenopalatine ganglion)
Supraorbital Foramen (supraorbital nerve,
Lacrimal Fossa :
Indicates one of two (fossa of lacrimal gland, or
fossa of lacremal sac in the pic.)
Contents of the Orbit :
Nerves (C.N II, III, IV, V, VI)
Lacrimal gland, Lacrimal sac, Nasolacrimal duct
Extra-ocular muscles and their movements:
Levator palpebrae superioris: innervated by the
oculomotor nerve and smooth muscle fibers are
innervated by sup. Cervical Sympathetic ganglion
superior rectus -superior when the eye is
medial rectus- medially
inferior rectus-inferior , the eye is abducted
Superior oblique-inferior when the eye is adducted
Inferior oblique-superior ,the eye is adducted
Orbital Septum: It is a membranous sheet that acts as the anterior boundary of the
It is attached to the orbital margin where it is continuous with the periosteum, and
then it goes through the eyelid as a sheet that thickens at the margin of the lid to
form the tarsal plate.
The tarsal plate contains the tarsal gland which is a sebaceous gland in the eyelid.
Review slid !
Name each of the numbered bones.
Which bone is thinnest?
Which is most likely to fracture after
Which is most likely to erode from
The bones are: (1)Sphenoid (2)Zygomatic (3)Maxilla (4)Lacrimal (5)Ethmoid
(6)Frontal. The ethmoid is the thinnest bone and most likely to perforate from
an eroding sinus infection (this happens mostly in kids). The maxillary floor
is most likely to fracture from blunt injury.
What is the function of the Orbit ?
The orbit holds the eye in the correct position.
The three basic structures that determine globe position of the eye are the bony
orbits, the ligament and muscle system & the orbital fat.
The orbit also protects the eye because the bones surrounding the eye “stick out”
further than the eye, objects tend to hit the orbit and not the eye.
Transmits nerves and blood vessels.
Clinical features of orbit diseases:
Despite the number of different tissues present in the orbit, the
expression of disease due to different pathologies is often similar.
Clinical features are:
1. Exophthalmos (proptosis)
4. Eyelid and conjunctival changes
6. Visual acuity disturbances
It is a protrusion of the eyeball.
could be unilateral or bilateral.
Bilateral proptosis Unilateral proptosis
Causes are classified into:
1. Intra-conal lesions: the lesion lies
within the cone formed by extra-
ocular muscles, thus the eye globe
is displaced directly forwards, e.g.
most commonly dysthyroid eye
disease, others like Optic nerve
2. Extra-conal lesions: the lesion is
outside the cone, so the eye is
displaced to one side, e.g. mostly
tumors, tumor of the lacrimal
gland displaces the globe nasally.
The most common cause is Graves
disease, it usually causes bilateral
Infectious (Orbital cellulitis)
Orbital Inflammatory disease
Vasculitis (wegener’s granulomatosis)
Neoplastic (unilateral): Lacrimal,
Orbital vascular disease (orbital
varices...causes transient proptosis on
o Buphthalmos ( congenital open
o Contralateral enophthalmos
o Ipsilateral lid retraction
Approach to Exophthalmos:
duration, rate of onset.
associated ocular symptoms (pain, decreased visual acuity or field, diplopia,
transient visual loss).
complaints of foreign body sensation or dry gritty eyes
history of trauma
Slow onset usually indicates benign tumors.
Fast onset indicates inflammatory disorder
malignant tumors, caroticocavernous sinus fistula.
intermittent onset indicates orbital varices,induced by
increasing the cephalic (head) venous pressure.
Full ophthalmic & systemic examination
Treatment :depends on the underlying cause, but if left untreated it could lead to:
1. Failure of the eyelids to close, causing corneal ulcerations and damage.
2. Compression on the optic nerve or ophthalmic artery leading to blindness
The amount of ocular protrusion measured (with
Hertel Exophthalmometer) from the lateral orbital rim
(zygomatic bone) to the corneal apex.
> 21 mm or a 2mm
the two eyes is
If it is left untreated
it could lead to:
Failure of the eyelid to close
leading to corneal damage ,
ulceration , & Possibly perforation
Compression on the optic nerve or
ophthalmic artery leading to
Restriction of eye movements &
Definition: Relative recession (backward or
downward displacement) of the globe into the bony
•Presents clinically as a sunken appearance to the eye
The doctor said this is mostly ptosis , sorry !
U can check slid 17 for a better photo
CAUSES OF ENOPHTHALMOS:
1. Primary enophthalmos indicates a
congenital etiology( Postnatal,
inadequate, orbital cavity
2. Acquired ( secondary):
- * Blow out trauma
- * Postsurgical muscle shortening
- Horner’s Syndrome .. Will cause
aberrant enophthalmos ; due to
Treatment : involves reconstruction of the bony
orbit with restoration of bony orbital volume and
repositioning of the globe.
Complications : Long-standing enophthalmos,
especially associated with very extensive orbital
trauma, may be associated with severe orbital
scarring, and correction can be very difficult or
Investigation of orbital disease
3. Systemic tests
depending on the
Fun fact !
An ostrich’s eye is larger than
its brain !
Differential diagnosis of orbital
Disorders of extra-ocular
muscles (Dysthyroid eye
disease and ocular myositis,
Infective disorders (orbital
cellulitis and preseptal
(Sarcoidosis, orbital pseudo-
tumors caused by
fistula, orbital varix, capillary
Orbital tumors (lacrimal
gland tumors, meningioma of
the optic nerve, optic nerve
by Shorooq Abdoh
You can’t depend on your eyes when your
imagination is out