2027 ICD-10-CM Diagnosis Code S21.90XDUnspecified open wound of unspecified part of thorax, subsequent encounter

ICD-10-CM Codes›S00–T88›S20-S29›S21

ICD-10-CM S21.90XD
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

S21.90XD is a billable ICD-10-CM diagnosis code for unspecified open wound of unspecified part of thorax, subsequent encounter. The 7th character D marks it as a subsequent encounter code, used during routine care in the healing or recovery phase. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 949 through 950. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Open wounds of trunk, subsequent encounter.

Code Identity

ICD-10-CM Code
S21.90XD
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified open wound of unspecified part of thorax, subsequent encounter
Short Description
Unsp open wound of unspecified part of thorax, subs encntr
Parent Code
S21.90
Unspecified open wound of unspecified part of thorax

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS20-S29Injuries to the thorax
CategoryS21Open wound of thorax
This CodeS21.90XDUnspecified open wound of unspecified part of thorax, subsequent encounter

Present on Admission (POA)Billing

S21.90XD is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Injuries to the thorax (S20-S29).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute lung injury
  • Anterior cord syndrome due to open fracture of T1-T6 level
  • Burst fracture of thoracic vertebra
  • Central cord syndrome of thoracic spinal cord due to injury of spinal cord at T7 - T12 level
  • Central cord syndrome of thoracic spinal cord due to open fracture at T1-T6 level
  • Central cord syndrome of thoracic spinal cord due to open fracture at T7-T12 level
  • Central cord syndrome of thoracic spinal cord due to traumatic injury
  • Closed injury of lung
  • Complete spinal cord injury at T1-T6 level
  • Complete spinal cord injury at T7-T12 level
  • Contusion of lung
  • Contusion of lung with open wound into thorax
  • Contusion to heart
  • Contusion to heart with open wound into thorax
  • Direct acute lung injury
  • Dislocation of costovertebral joint
  • Extravasation injury
  • Fracture of eight OR more ribs
  • Fracture of five ribs
  • Fracture of four ribs
  • Fracture of multiple left ribs
  • Fracture of multiple right ribs
  • Fracture of one rib
  • Fracture of seven ribs
  • Fracture of six ribs
  • Fracture of spinous process of thoracic vertebra
  • Fracture of three ribs
  • Fracture of transverse process of thoracic vertebra
  • Fracture of two ribs
  • Fractures involving thorax with lower back and pelvis
  • Fractures involving thorax with lower back and pelvis with limb
  • Glass in chest
  • Glass in trunk
  • Heart injury, closed
  • Heart injury, open
  • Heart laceration with open wound into thorax, with penetration of heart chambers
  • Hemopericardium
  • Hemopneumothorax
  • Hemothorax
  • Injury of bronchus with open wound into thoracic cavity
  • Injury of cutaneous sensory nerve of upper limb
  • Injury of diaphragm with open wound into cavity
  • Injury of esophagus with open wound into thoracic cavity
  • Injury of heart with hemopericardium
  • Injury of heart with open wound into thorax
  • Injury of intercostobrachial nerve
  • Injury of lung with open wound into thorax
  • Injury of pleura
  • Injury of subclavian artery
  • Injury of subclavian vein
  • Injury of thoracic cavity
  • Injury of thoracic duct
  • Injury of thoracic trachea
  • Injury of thoracic viscus with open wound into thoracic cavity
  • Injury of thymus gland
  • Laceration of heart
  • Laceration of heart with penetration of heart chambers
  • Laceration of lung
  • Long thoracic nerve injury
  • Long thoracic nerve lesion
  • Lung laceration with open wound into thorax
  • Multiple fractures of upper limb with sternum
  • Multiple injuries of intrathoracic organs
  • Multiple injuries of thorax
  • Multiple intrathoracic organ injury with open wound into cavity
  • Multiple open wounds of thoracic wall
  • Open bilateral fracture of multiple ribs
  • Open division of ligament of thoracic vertebral column
  • Open division, chondrosternal ligament
  • Open division, costal cartilage ligament
  • Open division, rib ligament
  • Open division, sternal ligament
  • Open fracture involving thorax with lower back and pelvis and limbs
  • Open fracture of bone of thorax
  • Open fracture of eight OR more ribs
  • Open fracture of five ribs
  • Open fracture of four ribs
  • Open fracture of multiple left ribs
  • Open fracture of multiple ribs
  • Open fracture of multiple right ribs
  • Open fracture of one left rib
  • Open fracture of one rib
  • Open fracture of one right rib
  • Open fracture of seven ribs
  • Open fracture of six ribs
  • Open fracture of T1-T6 level with spinal cord injury
  • Open fracture of T7-T12 level with incomplete spinal cord lesion
  • Open fracture of T7-T12 level with spinal cord injury
  • Open fracture of three ribs
  • Open fracture of two ribs
  • Open fracture thoracic vertebra
  • Open fracture thoracic vertebra, burst
  • Open fracture thoracic vertebra, posterior arch
  • Open fracture thoracic vertebra, spinous process
  • Open fracture thoracic vertebra, spondylolysis
  • Open fracture thoracic vertebra, transverse process
  • Open fracture thoracic vertebra, tricolumnar
  • Open fracture thoracic vertebra, wedge
  • Open heart injury with hemopericardium
  • Open injury of bronchus
  • Open injury of diaphragm
  • Open injury of intercostobrachial nerve
  • Open injury of lung
  • Open injury of pleura
  • Open injury of thoracic duct
  • Open injury of thoracic trachea
  • Open injury of thymus
  • Open injury, long thoracic nerve
  • Open injury, subclavian artery
  • Open injury, subclavian vein
  • Open multiple fracture of thoracic spine
  • Open multiple fractures of upper limb with sternum
  • Open spinal fracture with anterior thoracic cord lesion, T1-6
  • Open spinal fracture with complete thoracic cord lesion, T1-6
  • Open spinal fracture with complete thoracic cord lesion, T7-12
  • Open spinal fracture with posterior thoracic cord lesion, T1-6
  • Open spinal fracture with posterior thoracic cord lesion, T7-12
  • Open traumatic dislocation costovertebral joint
  • Open traumatic dislocation of costochondral joint
  • Open traumatic subluxation costovertebral joint
  • Open traumatic subluxation of costochondral joint
  • Open wound of thorax
  • Open wound of trachea
  • Open wounds involving thorax with abdomen, lower back and pelvis
  • Penetrating wound of lung
  • Penetrating wound of thorax
  • Posterior cord syndrome due to open fracture of T1-T6 level
  • Posterior cord syndrome due to open fracture of T7-T12 level
  • Spondylolysis of thoracic vertebra
  • Structural abnormality of thoracic duct
  • Subluxation of costochondral joint
  • Subluxation of costovertebral joint
  • Three column fracture of thoracic vertebra
  • Traumatic anterior cord syndrome
  • Traumatic hemopericardium
  • Traumatic hemothorax
  • Traumatic hemothorax with open wound into thorax
  • Traumatic pneumohemothorax
  • Traumatic pneumohemothorax with open wound into thorax
  • Traumatic pneumothorax
  • Traumatic pneumothorax with open wound into thorax
  • Wedge fracture of thoracic vertebra
  • Wedge fracture of vertebra

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Open wound of thorax (S21). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027, published by CMS and the National Center for Health Statistics.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to S21.90XD: its own notes plus those printed at S21, block S20-S29, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Block S20-S29 Injuries to the thorax applies to 1,602 codes
  • injuries of breast
  • injuries of chest (wall)
  • injuries of interscapular area

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From S21 Open wound of thorax applies to 288 codes
  • traumatic amputation (partial) of thorax (S28.1)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Block S20-S29 Injuries to the thorax applies to 1,602 codes
  • 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)
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • code to identify any retained foreign body, if applicable (Z18.-)

Code Also

A second code may be needed to fully describe the condition; the note gives no sequencing direction.

From S21 Open wound of thorax applies to 288 codes
  • 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

Notes

General instructions on how these codes are used.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
  • The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

7th Character

Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.

From S21 Open wound of thorax applies to 288 codes
  • The appropriate 7th character is to be added to each code from category S21
Values for category S21 Encounter: Initial, Subsequent, Sequela
  • Ainitial encounter
  • Dsubsequent encounter this code
  • Ssequela

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name S21.90XD, its category, or a range that includes it.

Code Also 6

These codes say S21.90XD may also be needed to fully describe the condition. The note gives no sequencing direction.

  • S23.1 Subluxation and dislocation of thoracic vertebra
    open wound of thorax (S21.-) names S21.-, which includes this code
  • S24 Injury of nerves and spinal cord at thorax level
    open wound of thorax (S21.-) names S21.-, which includes this code
  • S25 Injury of blood vessels of thorax
    any associated open wound (S21.-) names S21.-, which includes this code
  • S26 Injury of heart
    open wound of thorax (S21.-) names S21.-, which includes this code
  • S27 Injury of other and unspecified intrathoracic organs
    any associated open wound of thorax (S21.-) names S21.-, which includes this code
  • S29 Other and unspecified injuries of thorax
    any associated open wound (S21.-) names S21.-, which includes this code

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INJ050
Open wounds of trunk, subsequent encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Chest Injuries and Disorders

The chest is the part of your body between your neck and your abdomen (belly). The medical term for your chest is thorax.

The full article covers:

  • What is the chest?
  • What are chest injuries and disorders?
  • How are chest injuries and disorders diagnosed?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert S21.90XD to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
V58.89 Other specfied aftercare
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About S21.90XDOverview

Is S21.90XD (Unspecified open wound of unspecified part of thorax) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unspecified open wound of unspecified part of thorax, subsequent encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What does the 7th character D in S21.90XD mean?

The final character D marks a subsequent encounter: use it for routine care while the unspecified open wound of unspecified part of thorax is healing, after active treatment has ended.

What MS-DRG does S21.90XD group to?

When unspecified open wound of unspecified part of thorax, subsequent encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 950, 949, with relative weights from 0.7661 to 1.1231 depending on complications. Higher weights mean higher Medicare reimbursement.

Is S21.90XD exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for unspecified open wound of unspecified part of thorax, subsequent encounter on inpatient claims. The code appears in the Injuries to the thorax (S20-S29) range of the CMS exempt list.

Can S21.90XD be reported with S28.1?

Not as a rule. The Excludes1 note at S21, which applies to S21.90XD, lists "traumatic amputation (partial) of thorax (S28.1)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).