Two patients with “black eyes” sustained in
altercations (one black eye each). In both patients, the globe was
intact. Visual acuity and extra-ocular movements were normal.
- What are the radiographic findings in these
- (Figures 1 and 2)
Patient 1A—(A) Waters
(B) Caldwell view.
In both of these patients, air is seen within the orbit—orbital
emphysema. It appears as a radiolucent (dark) area in the superior
portion of the right orbit just below the superior orbital rim (Figures 1 and 2). This is caused by a fracture through one of the walls
of the orbit into an adjacent air-filled sinus. The fracture is
either through the orbital floor into the maxillary sinus, or the
medial orbital wall (lamina papyracea) into the ethmoid air cells.
Orbital emphysema is one of the findings of a “blow-out” fracture,
although it is not unique to that fracture.
A “blow-out” fracture occurs
when the anterior orbit sustains an impact by an object of larger
diameter than the orbit itself, e.g., a baseball or a fist. The
blow causes increased intraorbital pressure fracturing its weakest
part (the orbital floor or medial orbital wall) and not the globe
itself (Figure 3). However, given this mechanism of injury, there
is a high incidence of ocular injury (hyphema, vitreous hemorrhage,
retinal detachment). An alternative mechanism of injury is a blow
to the inferior orbital rim that causes buckling and a fracture
of the orbital floor.
Blowout fracture of the orbital floor.
The fracture can cause entrapment of the inferior rectus muscle
and injury to the infraorbital nerve.
[From Scaletta TA, Schaider JJ: Emergent
Management of Trauma, McGraw-Hill, 1996, with permission.]
Radiographic signs of a blow-out
fracture include soft tissue changes,
which are frequently more easily seen than the fracture itself (Table
1). These soft tissue signs include overlying soft tissue swelling,
a maxillary sinus opacification or air/fluid level, and
Table 1 Radiographic Signs of a Blow-Out Fracture ||Download (.pdf)
Table 1 Radiographic Signs of a Blow-Out Fracture
|Overlying soft tissue swelling (nonspecific, occurs with
and without fractures)|
|Orbital emphysema (especially medial orbital wall fractures)|
|Maxillary sinus opacification or air/fluid level (upright Waters view)|
|Herniation of orbital contents into the roof of maxillary
sinus (“tear-drop” sign)|
|Orbital floor (fine white line) is obliterated, widened, displaced downward (trap-door sign)
or fragmented and seen as a bright white line ...|