A 27 year old male presents after a motor vehicle accident, He has focal tenderness over his sternum which is worse with movement and deep inspiration.
Ultrasound excludes large pneumothorax but you wonder whether you can see a sternal fracture.
Describe and interpret these scans
Image 1: Longitudinal view sternum; The linear transducer is placed in sagittal section over the sternum. Sliding it from the sternal notch to the xiphisternum shows the manubrium, then the sterno-manubrial junction (a cartilaginous joint) and then the sternum.
A transverse fracture is seen just proximal to the point the third costal cartilage joins the sternum. The proximal and distal sternum move relative to one another with inspiration, proving the fracture involves both cortices.
In adults the sterno-manubrial junction at the level of the second costal cartilage is clearly identified with ultrasound and should not be confused with a fracture. In children there are numerous ossification centres in the sternum and these should not be confused with fractures (sternebrae). Congenital abnormalities of the sternum (such as a “bullet hole“) can also cause confusion.
Patients with an isolated sternal fracture are usually able to precisely localize their worst pain. Scan at this point and search for a clear lack of continuity in the anterior sternal cortex that runs transversely. You often see a small associated hypoechoic haematoma. Where the two parts of the sternum move separately with respiration it can be inferred the fracture involves both cortical surfaces.