Eur J Anat, 14 (2): 99-103 (2010)

Three unilateral recti sternalis muscles - an unusual variation and its clinical significance

Ramachandran Kalpana¹, Kothandaraman Usha²

¹epartment of Anatomy, Sri Muthukumaran Medical College Hospital & Research Institute, Chennai, India.²Department of Anatomy, Meenakshi Medical College & Research Institute, Kanchipuram, India.

ABSTRACT The sternalis muscle is an uncommon anatomic variation. We report a case of three unilateral recti sternalis muscles in a 60 year old male cadaver. All three muscles were slender and had a common origin from the right fourth sterno-chondral junction and partly from the lateral half of sternum. All three muscles continued up to the second costal cartilage, where they became inserted. The 3 muscles were medial, intermediate and lateral in position, and were named ST1, ST2, and ST3 respectively. The nerve supply to all three muscles was from the right third intercostal nerve through its anterior cutaneous branch. The clinical significance of this uncommon variant is discussed.

Keywords: Rectus sternalis, Unilateral, Intercostal nerve, Mammogram