Emergency Central is a collection of disease, drug, and test information including 5-Minute Emergency Medicine Consult, Davis’s Drug, McGraw-Hill Medical’s Diagnosaurus®, Pocket Guide to Diagnostic Tests, and MEDLINE Journals created for emergency medicine professionals. Explore these free sample topics:
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- Defined as an orbital floor fracture without orbital rim involvement
- 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 globe to the weakest structural point: The orbital floor
- Transmitted force “blows out” or fractures the orbital floor.
- 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
EtiologyCaused by a projectile which 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 fracture.
- 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:
- These children may present with marked nausea, vomiting, headache, and irritability suggestive of a head injury that commonly distracts from the true diagnosis.