Transversus thoracis muscle
（重定向自Musculus transversus thoracis）
The transversus thoracis muscle (/trænzˈvɛrsəs θəˈreɪsᵻs/) 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. It is in the same layer as the subcostal muscles and the innermost intercostal muscles.