2027 ICD-10-CM Diagnosis Code S56.309SUnspecified injury of extensor or abductor muscles, fascia and tendons of unspecified thumb at forearm level, sequela
S56.309S is a billable ICD-10-CM diagnosis code for unspecified injury of extensor or abductor muscles, fascia and tendons of unspecified thumb at forearm level, sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 913 through 914. The code is exempt from POA reporting. Coders also document this condition as injury of extensor or abductor muscles and tendons of thumb at forearm level. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Injury, sequela.
Code Identity
Code Classification
Present on Admission (POA)Billing
S56.309S is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Injuries to the elbow and forearm (S50-S59).
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Injury of extensor or abductor muscles and tendons of thumb at forearm level
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Injury of muscle, fascia and tendon at forearm level (S56). 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 S56.309S: its own notes plus those printed at S56, block S50-S59, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.
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.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- 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.
Notes
General instructions on how these codes are used.
- 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.
- The appropriate 7th character is to be added to each code from category S56
- Ainitial encounter
- Dsubsequent encounter
- Ssequela this code
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name S56.309S, its category, or a range that includes it.
Excludes2 2
These codes carry an Excludes2 note naming S56.309S: its condition is not part of those codes, and both may be reported when the patient has both.
- S46 Injury of muscle, fascia and tendon at shoulder and upper arm levelinjury of muscle, fascia and tendon at elbow (S56.-) names S56.-, which includes this code
- S53 Dislocation and sprain of joints and ligaments of elbowstrain of muscle, fascia and tendon at forearm level (S56.-) names S56.-, which includes this code
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Arm Injuries and Disorders
Of the 206 bones in your body, three of them are in your arm: the humerus, radius, and ulna. Your arms are also made up of muscles, joints, tendons, and other connective tissue. Injuries to any of these parts of the arm can occur during sports, a fall, or an accident.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert S56.309S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S56.309SOverview
Is S56.309S a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report unspecified injury of extensor or abductor muscles, fascia and tendons of unspecified thumb at forearm level, sequela on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character S in S56.309S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the unspecified injury of extensor or abductor muscles, fascia and tendons of unspecified thumb at forearm level itself has resolved, not the original event.
What MS-DRG does S56.309S group to?
When unspecified injury of extensor or abductor muscles, fascia and tendons of unspecified thumb at forearm level, sequela is the principal diagnosis on an inpatient stay, it groups to MS-DRG 914, 913, with relative weights from 0.9281 to 1.5448 depending on complications. Higher weights mean higher Medicare reimbursement.
Is S56.309S 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 injury of extensor or abductor muscles, fascia and tendons of unspecified thumb at forearm level, sequela on inpatient claims. The code appears in the Injuries to the elbow and forearm (S50-S59) range of the CMS exempt list.
What is the ICD-9 equivalent of S56.309S?
Under the General Equivalence Mappings, unspecified injury of extensor or abductor muscles, fascia and tendons of unspecified thumb at forearm level, sequela converts to ICD-9-CM 908.9 (late effect injury NOS). The mapping is approximate, so confirm the match fits the documentation.
