Sternalis muscle: a new crossed subtype, classification, and surgical applications

Area of Science:

• Anatomy
• Radiology
• Plastic Surgery

Background:

• The sternalis muscle is an anatomical variation often overlooked by clinicians.
• Its superficial location can lead to misinterpretation as pathology on medical imaging.
• This variation can complicate breast surgery and diagnostic procedures.

Purpose of the Study:

• To investigate the prevalence of sternalis muscle variations in the anterior thoracic wall.
• To document and classify rare sternalis muscle variants.
• To highlight the clinical and surgical significance of the sternalis muscle.

Main Methods:

• Anatomical dissection of 45 human cadavers (90 hemithoraces).
• Detailed examination of the anterior thoracic wall for longitudinally placed muscles.
• Documentation of any identified sternalis muscle variations, including origin, insertion, and morphology.

Main Results:

• A rare case of a crossed-type sternalis muscle was identified in an 83-year-old male.
• This variant originated from the sternocleidomastoid muscle and inserted into the subcostal arch.
• The observed variant did not fit existing sternalis muscle classifications.

Conclusions:

• The sternalis muscle, especially rare variants, requires increased awareness among clinicians and surgeons.
• Accurate identification of sternalis muscle variations is crucial for differential diagnosis in mammography and other imaging.
• The sternalis muscle's superficial location makes it a potential resource for reconstructive plastic surgery.