ORBIT- ANATOMY

DR. CHRISTINA SAMUEL

Develops from mesenchyme by ossification

Lacrimal Palatine Maxillary Zygomatic Frontal Sphenoid Ethmoid

28-30ml volume

DEVELOPMENT

Roof Floor Side walls Orbital apex

Boundaries of Orbit

Roof of orbit Frontal bone [Orbital plate] & lesser wing of

sphenoid

Separated from frontal sinus and anteriorcranial fossa above

Lacrimal gland fossa and trochlear fossabehind orbital rim

Medial wall

Body of sphenoidEthmoidLacrimalMaxilla[frontal process]

Floor of orbit

MaxillaZygomaticPalatine

Triangular segment- thinnestInferior orbital groove

Lateral wall

Greater wing –sphenoidOrbital surface –Frontal process of zygomatic

Inferiorly – inf orbital fissureMedially – sup orbital fissure

APEX

Eye ball Orbital fat Connective tissue system Blood vessels Nerves Extraocular muscles

Contents of orbit

Def: Purulent inflammation of the cellular tissue of the orbit.

Cause: -Spread of inflammation from neighboring

parts – nasal sinuses, Dacryocystitis, dental infection, deep injuries, retained foreign body,

-septic operations, DCR, RD, SQUINT-posterior extension of suppurative infection of

eye lid, panophthalmitis, facial erysipelas, - Metastases in pyaemia

Orbital cellulitis

Streptococcus pneumoniae. Staphylococcus aureusStreptococcus pyogenesHaemophilus influenzae. (children below 5 years)

Causative organisms

1. Swelling, erythema, warmth, pain, tendernes of the lid

2. Orbital abscess pointing on the skin or conjunctiva

Clinical features

3. Proptosis – lateral and down 4. Restriction and pain of ocular movements5. Diplopia 6. Afferent pupillary defect 7. Diminished vision due to compression of

optic nerve, its blood supply, optic neuritis

1. Periorbital abscess 2. Exposure keratopathy 3. C.R.A and C.R.V occlusion 4. Panophthalmitis 5. Intracranial complications - meningitis, brain abscess, - Cavernous Sinus thrombosis

Complications

1. T.C.D.C,ESR 2. CT orbit, sinus, brain 3. Blood, nasal, conjunctival and

throat culture and sensitivity

Investigations

1. Broad spectrum antibiotic 2. N.S.A.I.D3. Steroids 4. Close monitoring by

ophthalmologist, neuro surgeon, ENT surgeon

5. Surgical – drainage of the abscess, biopsy, orbital decompression.

Treatment

Thank you