The sternalis is a long thin muscle which expands via the sternocleidomastoid to the rectus abdominis accompanying the sternum. Compared to bilateral variant the sternalis is occurs twice as unilateral variant and develops the same in male and female patients. The muscle is superficial and medial towards the pectoralis major muscle.
The sternalis is a muscle which passes accompanying the anterior part of the body of the sternum. It is located superficially and parallel towards the sternum.
The sternalis muscle typically emerges via the upper part of the sternum and can show changing attachments such as the pectoral fascia, lower ribs, costal cartilages, rectus sheath, aponeurosis of the abdominal external oblique muscle. There is yet a lot of dispute about its innervation and its embryonic genesis. Its genesis and attachment are variable.
The sternalis has not been revealed to cause any pathology. Peculiarity along with the muscle can create concern when seen on a mammogram and has even brought about biopsy.
A recent study categorized the sternalis into three class depending on morphology.
- Class I (one head and one belly).
- Class II (two-headed/multi-headed).
- Class III (two-bellied/multi-bellied).
Class I, the one head and one belly was seen in the majority of revealed cases (58.5%), class II in 18.1%, and class III in 23.4%.