Blow-Out Fracture
Basics
Description
Description
- Defined as an orbital floor fracture that results from sudden blunt trauma to the globe:
- Typically caused by the force of a projectile > half the size of the fist
- Force transmitted through the noncompressible structures of the glove to the weakest structural point, the orbital floor, causing it to “blow out”
- Orbital floor serves as roof to air-filled maxillary and ethmoid sinuses:
- Communication between the spaces results in orbital emphysema
- Orbit contains fat, which holds the globe in place:
- Orbital floor fracture may result in herniation of the fat on the inferior orbital surface into the maxillary or ethmoid sinuses
- Leads to enophthalmos owing to orbital volume loss and sinus congestion; fluid collection may occur secondary to edema and bleeding
- Infraorbital nerve runs through the bony canal 3 mm below the orbital floor:
- Injury may result in hypoesthesia of the ipsilateral cheek and upper lip
- To distinguish facial hypoesthesia related to local swelling from nerve injury: Test for sensation on the ipsilateral gingiva, which is within the infraorbital nerve distribution
- Inferior rectus and the inferior oblique muscle run along the orbital floor:
- Restriction of these extraocular muscles may occur because of entrapment within the fracture, contusion, or cranial nerve dysfunction
- Typically manifests as diplopia on upward gaze
- Inability to elevate the affected eye normally on exam
- Medial rectus located above the ethmoid sinus:
- Less commonly entrapped
- Diplopia on ipsilateral lateral gaze
Etiology
Caused by a projectile that strikes the globe. The force is transmitted through the noncompressible structures of the globe to the weakest structural point, the orbital floor resulting in a blow-out fractureEtiology
Pediatric Considerations
- Orbital roof fractures with associated CNS injuries more common in children
- Orbital floor fractures: Unlikely before 7 yr of age:
- Orbital floor is not as weak a point in the orbit due to lack of pneumatization of the paranasal sinuses
- Unfortunately fractures can occur in children and may result in unrecognized entrapment of the rectus muscle labeled the “white-eyed” fracture:
- Findings are subtle and there may be little associated soft tissue injury
- These children may present with marked nausea, vomiting, bradycardia, headache, and irritability suggestive of a head injury that commonly distracts from the true diagnosis
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Citation
Schaider, Jeffrey J., et al., editors. "Blow-Out Fracture." 5-Minute Emergency Consult, 5th ed., Lippincott Williams & Wilkins, 2016. Emergency Central, emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307014/all/Blow_Out_Fracture.
Blow-Out Fracture. In: Schaider JJJ, Barkin RMR, Hayden SRS, et al, eds. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2016. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307014/all/Blow_Out_Fracture. Accessed August 31, 2024.
Blow-Out Fracture. (2016). In Schaider, J. J., Barkin, R. M., Hayden, S. R., Wolfe, R. E., Barkin, A. Z., Shayne, P., & Rosen, P. (Eds.), 5-Minute Emergency Consult (5th ed.). Lippincott Williams & Wilkins. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307014/all/Blow_Out_Fracture
Blow-Out Fracture [Internet]. In: Schaider JJJ, Barkin RMR, Hayden SRS, Wolfe RER, Barkin AZA, Shayne PP, Rosen PP, editors. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2016. [cited 2024 August 31]. Available from: https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307014/all/Blow_Out_Fracture.
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