An 18-year-old woman was an unrestrained back seat passenger
of a car that was struck on the passenger side by another vehicle.
The automobile was significantly damaged on the side of the impact.
None of the other occupants of the car were injured. She was removed
from the vehicle and immobilized by the ambulance crew.
In the ED, she was alert and oriented, although anxious and crying.
The patient did not think she had lost consciousness, although she
could not recall all of the details of the collision. Her only complaint
was of lower back pain.
Her blood pressure was 110/70 mm Hg and pulse 100/min.
There were several superficial abrasions and glass fragments on
her forehead. Her neck, chest and abdomen were non-tender. There was
tenderness over the lower lumbar spine. Compression of her pelvis
caused pain but there was no abnormal mobility.
- What fractures are seen on her pelvis radiograph
- What was the mechanism of injury responsible for
- What other injuries would you suspect in this patient?
Because the pelvis is a nearly rigid ring-like structure, any
single break in the pelvis, especially if displaced, should be accompanied
by another break elsewhere in the pelvis. If a second break is not
immediately obvious, it must be carefully sought.
In Patient 6, there are bilateral pubic
rami fractures (Figure 2). This anterior fracture fragment,
owing to its characteristic appearance, is sometimes referred to
as a butterfly fracture (Figure 3).
One mechanism that can cause this injury is anterior impact to the
perineal area by an object that is straddled by the patient’s
legs—a straddle fracture (Figure
4). These bilateral pubic rami fractures constitute the two breaks
in the pelvic ring; an additional fracture need not be present.
However, anterior impact is not the mechanism of injury in many
butterfly-shaped pelvic fractures and was not the mechanism of injury
in this patient.
Detail of the patient’s pelvis radiograph showing
bilateral pubic rami fractures (arrows).
Slight irregularity at the pubic symphysis is normal. Arrowhead–fragment of windshield
glass lying on the stretcher.
A “butterfly” fracture fragment (bilateral
pubic rami fractures) produced by an anterior impact on the pubic
Straddle fracture. This
mechanism of bilateral pubic rami fractures is actually uncommon.
There is also a fracture through the right sacral
wing (Figure 5).