Orbital Blowout Fracture
Ophthalmology/Trauma: Orbital Wall Fractures
1. Pathophysiology
A blowout fracture is caused by blunt trauma to the globe (e.g., a ball or fist). A sudden increase in intraorbital pressure results in a fracture of the orbital wall, typically the floor (maxillary bone) or medial wall (ethmoid bone), as these are the thinnest areas.
2. Clinical Manifestations
| Sign/Symptom | Mechanism |
|---|---|
| Diplopia | Due to entrapment of the inferior rectus muscle (in floor fractures). |
| Infraorbital Nerve Anesthesia | Numbness in the cheek, upper lip, and gums due to nerve injury in the floor. |
| Enophthalmos | Sunken globe caused by increased orbital volume and fat prolapse. |
3. NEET High-Yield Pearls
- Entrapment: The inferior rectus is the most common muscle entrapped in orbital floor fractures, limiting upward gaze.
- Imaging: **CT Orbit** (coronal view is best) is the gold standard for visualizing the fracture and confirming muscle entrapment.
- “White-Eyed Blowout”: Common in children; minimal external signs of trauma, but severe muscle entrapment causing significant bradycardia/nausea (oculocardiac reflex). **Requires urgent surgical repair.**
- Management: Prophylactic antibiotics (to cover sinus pathogens) and surgical repair if there is significant enophthalmos, muscle entrapment, or persistent diplopia.