Computed tomography of the normal sternum.

The normal CT anatomy of the sternum was studied in 35 patients. In addition to the normal appearance of the sternum, normal variants that may mimic disease were often noted. In the manubrium, part of the posterior cortical margin was unsharp and irregular in 34 of 35 patients. Part of the anterior cortical margin was indistinct in 20 of the 35 patients. Angulation of the CT gantry to a position more nearly perpendicular to the manubrium improved the definition of the cortical margins. The body of the sternum was ovoid to rectangular and usually had sharp cortical margins. Sections through the manubriosternal joint and xyphoid often demonstrated irregular mottled calcifications and indistinct margins again simulating bony lesions. The rib insertions, sternal clavicular joints, and adjacent soft-tissue appearance also were evaluated.