S21

Non-Billable
ChapterS00–T88
Rankcategory
Official Description

Open wound of thorax

Metadata & Insights
  • •2026 ICD-10-CM Edition - Effective October 1, 2025.
  • •Non-billable category (requires more specific sub-code).
  • •Chapter 19: Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88).

CH19 Parent Instructions

Excludes2(Not included here)
Use Additional Code
  • code to identify any retained foreign body, if applicable (Z18.-)

S20-S29 Parent Instructions

Includes
  • injuries of breast
  • injuries of chest (wall)
  • injuries of interscapular area
Excludes2(Not included here)
  • burns and corrosions (T20-T32)
  • effects of foreign body in bronchus (T17.5)
  • effects of foreign body in esophagus (T18.1)
  • effects of foreign body in lung (T17.8)
  • effects of foreign body in trachea (T17.4)
  • frostbite (T33-T34)
  • injuries of axilla
  • injuries of clavicle
  • injuries of scapular region
  • injuries of shoulder
  • insect bite or sting, venomous (T63.4)

Instructional Notes

Excludes1(Not coded here)
  • traumatic amputation (partial) of thorax (S28.1)
Code Also
  • any associated injury, such as:
  • injury of heart (S26.-)
  • injury of intrathoracic organs (S27.-)
  • rib fracture (S22.3-, S22.4-)
  • spinal cord injury (S24.0-, S24.1-)
  • traumatic hemopneumothorax (S27.3)
  • traumatic hemothorax (S27.1)
  • traumatic pneumothorax (S27.0)
  • wound infection

Clinical Hierarchy

CH19Injury, poisoning and certain other consequences of external causes (S00-T88)
S20-S29Injuries to the thorax (S20-S29)
S21Open wound of thorax
S21.0Open wound of breast
S21.1Open wound of front wall of thorax without penetration into thoracic cavity
S21.2Open wound of back wall of thorax without penetration into thoracic cavity
S21.3Open wound of front wall of thorax with penetration into thoracic cavity
S21.4Open wound of back wall of thorax with penetration into thoracic cavity
S21.9Open wound of unspecified part of thorax

Applicable Ancestor Context

The following parent sections contain instructions or notes that apply to S21:

blockS20-S29
Injuries to the thorax (S20-S29)
View context instructions
chapterCH19
Injury, poisoning and certain other consequences of external causes (S00-T88)
View context instructions

Alphabetic Index Mentions

These are Diagnosis Index lookup paths that route to S21. Use them as entry terms for search, then confirm final coding instructions in the Tabular List and notes above.

25 raw paths
Bite (s) (animal) (human)6 unique routes
breast→S21
thorax, thoracic (wall)→S21(5 variants)
back→S21(2 variants)
with penetration into thoracic cavity→S21
front→S21(2 variants)
with penetration into thoracic cavity→S21
Laceration16 unique routes
breast→S21(2 variants)
with foreign body→S21
thorax, thoracic (wall)→S21(14 variants)
back→S21(4 variants)
with(3 variants)
foreign body→S21(2 variants)
with penetration into thoracic cavity→S21
penetration into thoracic cavity→S21
front→S21(4 variants)
with(3 variants)
foreign body→S21(2 variants)
with penetration into thoracic cavity→S21
penetration into thoracic cavity→S21
with foreign body→S21(5 variants)
back→S21(2 variants)
with penetration into thoracic cavity→S21
front→S21(2 variants)
with penetration into thoracic cavity→S21
Puncture3 unique routes
breast→S21(3 variants)
left→S21(2 variants)
with foreign body→S21

MS-DRG Classification

2026

No direct MS-DRG triggers identified.

Cross Reference

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