An unusual finding of the pectoralis major muscle: decussation of sternal fibers across the midline.

Variations of the pectoralis major muscle are commonly seen. However, during the routine dissection of an adult male cadaver, an apparently uncommon muscular variant was identified. In this cadaver, the sternal heads of the left and right pectoralis muscles crossed the midline and interdigitated with one another. In addition, the clavicular heads of both pectoralis major muscles were separated from the remaining parts of the muscles. Such anatomical variants such be kept in mind by clinicians and surgeons during patient evaluation and treatment.