This is an 8 year old boy who was playing with his 
brother who accidentally kicked him in the left side of 
the face with his knee. The boy developed epistaxis 
immediately after the injury and he complained of 
intermittent double vision in his left eye.  He did not 
loose consciousness, but his parents noted increased 
somnolence and 3 episodes of emesis.
     Past medical history is negative. 
     Exam:  VS T36.6, HR 90, RR 16, BP 137/83, 
oxygen saturation 100% in room air.  He is somnolent, 
but easily arousable.  Eyes:  Visual acuity 20/25 OU.  
There is no proptosis.  There is ecchymosis and 
swelling of his left lower eyelid.  There is mild left 
periorbital swelling but no obvious tenderness or step 
off deformity on palpation.  The cornea, lens and 
anterior chamber are clear.  There is no hyphema.  
Pupils are equal and reactive.  There is restricted 
upward and downward gaze in his left eye, but normal 
ab/adduction.  EOM's are normal in the right eye.  
Sensation in the distribution of the infraorbital nerve is 
intact.
     TM's clear, no blood.  There is blood in his nares.  
No septal swelling is noted.  His pharynx is clear.  His 
neck is nontender with full range of motion.  His chest 
is clear to auscultation.  Heart regular without murmurs.  
Abdomen nontender with active bowel sounds.  His 
speech is normal.  Deep tendon reflexes are normal.  
His strength is normal.
     A CT scan of the brain and orbits is obtained.

View CT scan.


     The brain is normal.  The CT cut shown is taken in 
the axial projection (i.e., the long axis of his body is 
perpendicular to the plane of the CT scanner) through 
the orbits using a "bone window" contrast setting.  The 
black arrow points to the medial wall of the left orbit 
which is fractured and pushed medially.
     Additional coronal CT views are taken of the orbits 
by hyperextending his neck so that the long axis of his 
head is closer to being parallel with the plane of the CT 
scanner.  Since axial cuts are parallel with the floor of 
the orbit, some fractures of the orbital floor are not well 
visualized.  By repositioning the patient so that the CT 
cuts are perpendicular to the orbital floor, a fracture of 
the orbital floor can be more accurately visualized.

View coronal CT cut.


     These coronal views reveal a fracture of the left 
orbital floor (black arrow).  The white arrow points to the 
inferior rectus muscle protruding into the maxillary 
sinus through the orbital floor fracture site.  The clinical 
findings suggest that there may be entrapment of the 
left inferior rectus muscle, leading to restriction in 
upward and downward gaze and diplopia when trying to 
look in these directions.  The small depressed fracture 
of the medial wall of the left orbit with opacification of 
the left ethmoid air cells is again visible.  
     Fractures of the orbital floor may be difficult to 
visualize on an axial CT scan through the orbits since 
the orbital floor is parallel to the plane of the scan.  
Fractures are best seen when the fracture is 
perpendicular or oblique to the plane of the scan.  
Thus, when an orbital floor fracture is suspected, as in 
trauma to the orbit, coronal scans of the orbit should be 
obtained, provided that the patient can be positioned 
properly.

Orbital wall fractures:
     The orbital bones are very delicate and their 
thickness is similar to that of an eggshell.  Orbital wall 
fractures most often occur in the orbital floor and 
sometimes in the medial wall, because these are the 
weakest regions of the bony orbit.  The proximity of the 
paranasal sinuses, nerves, vessels, extraocular 
muscles, globe and other orbital structures predispose 
them to a wide variety of possible damage from injury 
producing orbital fractures.
     An orbital blow out fracture refers to a fracture of the 
orbital floor, usually without involvement of the orbital 
rim.  The impacting object typically has a diameter that 
is larger than that of the orbital opening.  Examples 
include a fist, tennis ball, baseball, snowball or door 
knob.  The mechanism of a blow out fracture is 
controversial.  There are two main theories that are 
likely:  1) The fracture results from a sudden increase in 
intraorbital pressure when the globe is being pushed 
posteriorly.  2) The fracture is the result of "buckling" 
forces which are transmitted to the orbital bones by 
transient deformity of the orbital rim.
     An aide to the evaluation of children with orbital 
fractures is the mnemonic HEADER:
     Hyphema:  Evaluate the child for bleeding in the 
anterior chamber and for other intraocular injuries.
     Emphysema:  Orbital emphysema is due to a 
fracture of the medial wall and/or inferior wall which 
permits communication between the ethmoid sinus 
and/or the maxillary sinus with the orbital contents.  In 
order to make the diagnosis of orbital emphysema 
clinically, the orbit should be palpated for crepitus.  
Subcutaneous air can be dramatic when the patient 
blows his/her nose.  Patients may notice eye swelling 
when blowing their nose.  Orbital emphysema may be 
visible on a plain radiograph of the orbit.  It is also 
visible on CT scans.
     Epistaxis:  A fracture of the medial orbital wall can 
result in a significant nose bleed.
     Anesthesia or hypoaesthesia in the distribution of 
the second branch of the trigeminal nerve must be 
suspected in any fracture involving the infraorbital 
canal.  The distribution involves the lower eyelid and 
the cheek down to the upper lip on the side of the 
injury.
     Diplopia:  Double vision has essentially two primary 
mechanisms:  1) A mechanical entrapment of an eye 
muscle, most commonly, the inferior rectus muscle, or 
the inferior oblique muscle.  2) A paralytic component 
where injury to the third cranial nerve has occurred.  
The third cranial nerve innervates both the inferior 
rectus and the inferior oblique muscle.  Hemorrhage 
and edema within the extraocular muscles may also 
cause transient paresis.
     Exophthalmos is secondary to intraorbital 
hemorrhage and edema which pushes the globe 
anteriorly.  However, a large fracture of the medial 
wall or orbital floor may result in enophthalmos.
     Restriction:  Entrapment of extraocular muscles and 
orbital tissue in the fracture site leads to decreased 
ocular motility.  With orbital floor fractures, the inferior 
rectus muscle most commonly is entrapped leading to 
limitation in upward gaze.  With medial wall fractures, 
limited abduction due to medial rectus incarceration 
may result.

Diagnosis:
     CT scanning is highly useful in the assessment of 
orbital trauma and associated injures to the brain and 
sinuses.  Coronal views (direct or reconstructed) should 
be requested when orbital trauma is present.
     Plain radiographs are not sufficient.  They may be 
helpful in confirming fractures and in the delineation of 
air-fluid levels in the paranasal sinuses, but they may 
fail to show the existence and extent of orbital 
fractures.
     Surgical repair of a fractured orbital wall would be 
indicated in the following instances:  1) Significant 
enophthalmos.  2) Diplopia in primary gaze or in a 
functional gaze.  3) Significant limitation of extraocular 
movements.

References:
     1.  Levin AV.  Eye trauma.  In:  Fleisher GR, Ludwig 
S (eds).  Textbook of Pediatric Emergency Medicine, 
3rd edition.  1993, Baltimore, MD, Williams and 
Wilkins, pp. 1200-1209.
     2.  Mead MD.  Evaluation and Initial Management of 
Patients with Ocular and Adnexal Trauma.  In:  Albert 
DM, Jakobiec FA (eds).  Principles and Practice of 
Ophthalmology.  1994, Philadelphia, Saunders, Volume 
5, pp. 3362-3375.
     3.  Friendly DS, Jaafar MS.  Ocular Trauma.  In:  
Eichelberger MR.  Pediatric Trauma.  1993, St. Louis, 
pp. 401-410.