n :  either of two openings transmitting nerves and blood vessels to or from the orbit:  a  :  one situated superiorly between the greater wing and the lesser wing of the sphenoid bone - called also superior orbital fissure , supraorbital fissure   b  :  one situated inferiorly between the greater wing of the sphenoid bone and the maxilla - called also inferior orbital fissure , infraorbital fissure , sphenomaxillary fissure  .
 
 
 
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