S21.209 - Unspecified open wound of unspecified back wall of thorax without penetration into thoracic cavity S21.2 - Open wound of back wall of thorax without penetration into thoracic cavity S21.20 - Unspecified open wound of back wall of thorax without penetration into thoracic cavity S21.209 - Unspecified open wound of unspecified back wall of thorax without penetration into thoracic cavity