Sternalis “mystery” muscle and its clinical implications

Abstract

Sternalis is an anomalous muscle found occasionally in the anterior part of the thorax. During routine dissection sternalis muscle was found in a male cadaver. This rare anatomic variant is reported in 8% of the population. In the present case, the muscle was found bilaterally, placed obliquely on either side of the sternum. It originated by tendinous fibres from the lower costal cartilages and inserted to the manubriosternal junction. The right side muscle was well developed whereas the left one was reduced in size. The pectoralis major and minor were normal. The knowledge of sternalis is important for radiologists and surgeons.