Transversus thoracis muscle :-
Muscle details :-
lies internal to the thoracic cage, anteriorly. It is a thin plane of muscular and tendinous fibers, situated upon the inner surface of the front wall of the chest.
Costal cartilages of last 3-4 true ribs, body of sternum and xiphoid process.
Ribs/costal cartilages 2-6 .