The sternalis muscle: radiologic findings on MDCT

The purpose of this study was to characterize and determine the prevalence of the sternalis muscle using 64-row multidetector computed tomography (MDCT).

We retrospectively reviewed MDCT chest scans that were performed in a hospital during the course of a month. The study population consisted of 948 consecutive patients (511 males and 467 females). On the MDCT scans the sternalis muscle was defined as the longitudinal muscle lying on and superficial to the pectoralis major muscle.

The prevalence of the sternalis muscle was 10.5 %. The muscle was present more frequently in females (13.0 %) compared to males (8.4 %) (P = 0.02). In the majority of patients, the muscle was located longitudinally in the parasternal position; however, in two patients it was positioned across the sternum. One hundred twenty were flat types, while the remaining five had oblique shapes. The muscle mean height, width and depth were 77.9 ± 25.1, 19.4 ± 12.2 and 2.8 ± 1.3 mm, respectively. The muscle was wider in males compared to females (P < 0.001).

Using MDCT, its prevalence was shown to be 10.5 %. This variant muscle can be differentiated from other pathological structures using its specific characteristic appearance.