Blow out fracture
- When a blunt object larger than the orbit makes forceful contact with the
orbital rim, rapid compression of the
tissues within the bony, confined space causes a large pressure increase
within the orbit.
- This increased pressure can generate sufficient force to fracture the wall
of the orbit, causing herniation
of orbital contents through the blow-out fracture.
- The floor and medial walls are the
weakest portions of the orbit and are most commonly involved.
- Approximately 20% of orbital
fractures are associated with injury to the globe, requiring dilated
ophthalmoscopy and computed tomography of the orbit for evaluation.
- Other physical findings may include
- entrapment of the ocular
nerves, i.e. medial rectus muscle, producing dysconjugate gaze.
from hemorrhage within the orbit
- "sunken eye" appearance
from herniation of orbital contents through the fracture.
- Tenderness along the
orbital rim or a fracture step-off
also may be present.
of the ipsilateral
cheek may occur due to damage to the infraorbital nerve, which
travels along the floor of the orbit.
- Lens disruption and retinal
detachment are possible consequences of severe trauma to the eye, but
visual changes are not dependent on
eye position, and neither condition in isolation would cause dysconjugate
- a collection of
blood in the anterior chamber
of the eye that is visualized easily with a hand-held ophthalmoscope or even
with the naked eye. Treatment =
- marked visual impairment
- soft, flattened eye and anterior
chamber due to decreased intraocular pressure.
- Treatment: emergent referral
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Advanced Trauma Life Support for Doctors: Student Course Manual. 6th
ed. Chicago, Ill: American College of Surgeons; 1997:411
Klein BR, Sears ML. Eye injury. Pediatr Rev. 1992;13:127-129
Levin AV. Eye trauma. In: Fleisher GR, Ludwig S, eds. Textbook of
Pediatric Emergency Medicine. 4th ed. Philadelphia, Pa: Lippincott
Williams & Wilkins; 2000:1397-1407