Orbit and Zygoma Fractures

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Orbit and Zygoma Fractures


Image The Orbit


Anatomy


The orbit is composed of seven bones:


 


•   Zygoma


•   Greater and lesser wing of the sphenoid


•   Ethmoid


•   Frontal


•   Palatine


•   Maxilla


•   Lacrimal


 


These seven bones create a bony pyramid with the optic canal at the apex. The orbit is comprised of the following structures


 




Image  Floor


Image  Roof of the maxillary sinus


Image  Medial wall


Image  Lamina papyracea of the ethmoid bone


Image  Lacrimal bone


Image  Lateral wall


Image  Zygoma and greater wing of the sphenoid bone


Image  Roof


Image  Frontal bone – floor of the frontal sinus


 


The medial wall is the weakest structure, followed by the floor. The roof and the lateral wall are generally the strongest. The optic nerve exits the optic canal situated superomedially and ~40 to 45 mm from the inferior orbital rim. The superior orbital fissure separates the greater and lesser wings of the sphenoid. From the superior orbital fissure traverses the


 


•   Oculomotor nerve (CN III)


•   Trochlear nerve (CN IV)


•   Abducens nerve (CN VI)


•   Ophthalmic division of the trigeminal nerve (CN V1)


The inferior orbital fissure provides passage of the


 


•   Maxillary division of trigeminal (CN V2)


•   Branches of sphenopalatine ganglion


•   Branches of the inferior ophthalmic vein


Physical Examination


Orbital fractures are usually associated with blunt trauma. Nearly 30% of orbital fractures will have injuries to the globe. It is important to perform a detailed ophthalmic exam that includes visual acuity, pupillary reaction, retinal exam, and red color saturation, as described in Chapter 7. Any deviation from normal warrants an emergent ophthalmic consultation.


Pathologic physical findings include


 


•   Orbital ecchymosis


•   Periorbital edema


•   Subconjunctival hemorrhage


•   Epistaxis


•   Orbital rim/zygoma bony step-offs


•   Diplopia


•   Extraocular muscle entrapment



Image  Examine the active range of motion of the extraocular muscles to rule out mechanical entrapment.


Image  In unconscious patients, perform the forced duction test: using Adson forceps grasp the inferior capsulopalpebral fascia of the inferior rectus muscle and gently rotate the globe, while feeling for any restrictions.


 


•   Intraorbital edema


•   Optic nerve neuropraxia


•   Pupillary shape – oblong pupil is suggestive of ocular perforation


•   Pupillary response – afferent pupillary defect (see Chapter 7)


•   Supraorbital, infraorbital, alveolar nerve paresthesias


•   Crepitus/subcutaneous emphysema – disruption of maxillary or ethmoid sinus mucosa


•   Enophthalmos – noticeably with >2 mm shift; however, rarely evident immediately postinjury because of edema


•   Proptosis/exophthalmos


•   Hyphema – fluid in the anterior chamber of the eye


•   Superior orbital fissure (SOF) syndrome – fractures of the SOF result in



Image  Fixed dilated pupil (CN III)


Image  Upper lid ptosis (CN III)


Image  Loss of corneal reflex (CN V1)


Image  Ophthalmoplegia (CN IV, CN VI)


•   Orbital apex syndrome – SOF syndrome plus impairment of optic nerve as it exists in the optic canal


•   Nausea, vomiting, bradycardia – oculocardiac response to extraocular muscle entrapment (Fig. 8–1

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Mar 12, 2016 | Posted by in General Surgery | Comments Off on Orbit and Zygoma Fractures

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