| S20.441 | External constriction of right back wall of thorax | NON-BILLABLE CODE |
| S20.441A | External constriction of right back wall of thorax, initial encounter | BILLABLE CODE |
| S20.441D | External constriction of right back wall of thorax, subsequent encounter | BILLABLE CODE |
| S20.441S | External constriction of right back wall of thorax, sequela | BILLABLE CODE |
| S20.442 | External constriction of left back wall of thorax | NON-BILLABLE CODE |
| S20.442A | External constriction of left back wall of thorax, initial encounter | BILLABLE CODE |
| S20.442D | External constriction of left back wall of thorax, subsequent encounter | BILLABLE CODE |
| S20.442S | External constriction of left back wall of thorax, sequela | BILLABLE CODE |
| S20.449 | External constriction of unspecified back wall of thorax | NON-BILLABLE CODE |
| S20.449A | External constriction of unspecified back wall of thorax, initial encounter | BILLABLE CODE |
| S20.449D | External constriction of unspecified back wall of thorax, subsequent encounter | BILLABLE CODE |
| S20.449S | External constriction of unspecified back wall of thorax, sequela | BILLABLE CODE |
