S20.40 - Unspecified superficial injuries of back wall of thorax S20.4 - Other and unspecified superficial injuries of back wall of thorax S20.40 - Unspecified superficial injuries of back wall of thorax S20.401 - Unspecified superficial injuries of right back wall of thorax S20.402 - Unspecified superficial injuries of left back wall of thorax S20.409 - Unspecified superficial injuries of unspecified back wall of thorax