Subdivision of thorax, which in humans is the posterior part of the thorax and is demarcated from the chest by the external surface of the posterolateral part of the rib cage and the anterior surface of the thoracic vertebral column; together with the chest, it constitutes the thorax. [ FMA:24217 ]
Synonyms: posterior part of thorax upper back dorsum of thorax thoracic back thoracic part of back