2027 ICD-10-CM Diagnosis Code S21.209DUnspecified open wound of unspecified back wall of thorax without penetration into thoracic cavity, subsequent encounter

ICD-10-CM Codes›S00–T88›S20-S29›S21

ICD-10-CM S21.209D
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

S21.209D is a billable ICD-10-CM diagnosis code for unspecified open wound of unspecified back wall of thorax without penetration into thoracic cavity, 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
S21.209D
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified open wound of unspecified back wall of thorax without penetration into thoracic cavity, subsequent encounter
Short Description
Unsp opn wnd unsp bk wl of thorax w/o penet thor cav, subs
Parent Code
S21.209
Unspecified open wound of unspecified back wall of thorax without penetration into thoracic cavity

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS20-S29Injuries to the thorax
CategoryS21Open wound of thorax
This CodeS21.209DUnspecified open wound of unspecified back wall of thorax without penetration into thoracic cavity, subsequent encounter

Present on Admission (POA)Billing

S21.209D 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.

  • Anterior cord syndrome due to injury at T7-T12 level
  • Anterior cord syndrome due to open fracture of T7-T12 level
  • Anterior lesion of thoracic spinal cord due to open dislocation of joint of thoracic spine
  • Anterior lesion of thoracic spine due to open subluxation of joint of thoracic spine
  • Central cord syndrome of thoracic spinal cord due to open dislocation of joint of thoracic spine
  • Central cord syndrome of thoracic spinal cord due to open subluxation of joint of thoracic spine
  • Central cord syndrome of thoracic spinal cord due to traumatic injury
  • Complete lesion of thoracic spinal cord due to open subluxation of joint of thoracic spine
  • Degloving injury back
  • Degloving injury chest wall
  • Degloving injury of trunk
  • Degloving injury, scapular area
  • Degloving injury, shoulder area
  • Dislocation of costovertebral joint
  • Dislocation of scapulothoracic joint
  • Fracture of first thoracic vertebra
  • Fracture of fourth thoracic vertebra
  • Fracture of second thoracic vertebra
  • Fracture of third thoracic vertebra
  • Glass in back
  • Lesion of thoracic spinal cord due to open dislocation of joint of thoracic spine
  • Lesion of thoracic spinal cord due to subluxation of joint of thoracic spine
  • Open dislocation of scapula
  • Open dislocation thoracic spine
  • Open fracture of first thoracic vertebra
  • Open fracture of fourth thoracic vertebra
  • Open fracture of second thoracic vertebra
  • Open fracture of T7-T12 level with incomplete spinal cord lesion
  • Open fracture of T7-T12 level with spinal cord injury
  • Open fracture of third thoracic vertebra
  • Open fracture of thoracic spine with spinal cord injury
  • Open spinal dislocation with complete thoracic cord lesion
  • Open subluxation thoracic spine
  • Open traumatic dislocation costovertebral joint
  • Open traumatic dislocation of scapulothoracic joint
  • Open wound of back
  • Open wound of back wall of thorax
  • Open wound of scapular region
  • Posterior cord syndrome of thoracic spinal cord due to open dislocation of joint of thoracic spine
  • Posterior cord syndrome of thoracic spinal cord due to open subluxation of joint of thoracic spine
  • Traumatic anterior cord syndrome
  • Traumatic dislocation of scapulothoracic joint

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 S21.209D: 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 S21.209D, its category, or a range that includes it.

Code Also 6

These codes say S21.209D 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

Back Injuries

Your back is made of bones, muscles, and other tissues extending from your neck to your pelvis. Back injuries can result from sports injuries, work around the house or in the garden, or a sudden jolt such as a car accident. The lower back is the most common site of back injuries and back pain. Common back injuries include :

Read the full article at MedlinePlus

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

Convert S21.209D 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 S21.209DOverview

Is S21.209D a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unspecified open wound of unspecified back wall of thorax without penetration into thoracic cavity, subsequent encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What does the 7th character D in S21.209D mean?

The final character D marks a subsequent encounter: use it for routine care while the unspecified open wound of unspecified back wall of thorax without penetration into thoracic cavity is healing, after active treatment has ended.

What MS-DRG does S21.209D group to?

When unspecified open wound of unspecified back wall of thorax without penetration into thoracic cavity, 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 S21.209D 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 back wall of thorax without penetration into thoracic cavity, subsequent encounter on inpatient claims. The code appears in the Injuries to the thorax (S20-S29) range of the CMS exempt list.

Can S21.209D be reported with S28.1?

Not as a rule. The Excludes1 note at S21, which applies to S21.209D, 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).