Sternal Fracture after a Car Accident
A 26-year-old man is involved in a motor vehicle collision. He is awake and alert, and complains of chest pain. On exam, his vitals are: 120/88 mm Hg, HR 122 beats/minute, RR 24 breaths/minute. On the cardiac monitor, he also has frequent premature ventricular complexes. On a chest X-ray, you see a fractured sternum.
You are concerned about cardiac injury and so you obtain an EKG seen here.
The answer is B - Right Ventricle, this is because the right ventricle lies most anterior in the thorax, immediately behind the sternum. Additionally, sternum fractures required a great amount of force and so the presence of this finding on X-ray suggests a high velocity impact. This puts patients at risk for myocardial contusions which can lead to arrhythmias, chest pain, difficulty breathing, palpitations, etc.
The patient in this case complaints of chest pain, along with an EKG showing anterior T-wave inversions suggestive of myocardial injury; additionally, serum troponin levels may be elevated further increasing the suspicion of myocardial injury. If the patient has any of these signs of myocardial injury, admission for telemetry monitoring should be strongly considered.
Although not mentioned in the case stem, these patients can also have deformities on inspection or palpation such as ecchymosis, or palpable deformities from the fracture. Also when suspecting a sternal fracture, a lateral X-ray must be obtained since these can be missed on AP/PA Chest X-ray films.
Answer A, C, E are less commonly injured in sternal fractures given they lie more posterior within the thorax.
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