2027 ICD-10-CM Diagnosis Code S46.129ALaceration of muscle, fascia and tendon of long head of biceps, unspecified arm, initial encounter

ICD-10-CM Codes›S00–T88›S40-S49›S46

ICD-10-CM S46.129A
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

S46.129A is a billable ICD-10-CM diagnosis code for laceration of muscle, fascia and tendon of long head of biceps, unspecified arm, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 564 through 566, 963 through 965. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 54 closely related codes. The code is flagged as an unspecified code, since codes identifying laterality exist in the same family. Coders also document this condition as injury of fascia of long head of biceps. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Open wounds to limbs, initial encounter.

Code Identity

ICD-10-CM Code
S46.129A
Billable Status
Yes — Valid for Submission
Code Describes
Laceration of muscle, fascia and tendon of long head of biceps, unspecified arm, initial encounter
Short Description
Laceration of musc/fasc/tend long hd bicep, unsp arm, init
Parent Code
S46.129
Laceration of muscle, fascia and tendon of long head of biceps, unspecified arm

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS40-S49Injuries to the shoulder and upper arm
CategoryS46Injury of muscle, fascia and tendon at shoulder and upper arm level
This CodeS46.129ALaceration of muscle, fascia and tendon of long head of biceps, unspecified arm, initial encounter

Code EditsBilling

Medicare Code Editor checks that affect claim validity for S46.129A.

Unspecified codes
Unspecified codes exist in the ICD-10-CM classification for circumstances when documentation in the medical record does not provide the level of detail needed to support reporting a more specific code. However, in the inpatient setting, there should generally be very limited and rare circumstances for which the laterality (right, left, bilateral) of a condition is unable to be documented and reported. The following pages contain the list of unspecified ICD-10-CM diagnosis codes for which there is a more specific code to identify laterality (right, left, bilateral) within that code family.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Injury of fascia of long head of biceps
  • Injury of muscle of long head of biceps
  • Laceration of biceps brachii
  • Laceration of fascia of long head of biceps brachii
  • Laceration of muscle of long head of biceps brachii
  • Laceration of tendon of biceps brachii
  • Laceration of tendon of long head of biceps brachii
  • Laceration of tendon of upper arm

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Injury of muscle, fascia and tendon at shoulder and upper arm level (S46). 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 S46.129A: its own notes plus those printed at S46, block S40-S49, 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 S40-S49 Injuries to the shoulder and upper arm applies to 2,730 codes
  • injuries of axilla
  • injuries of scapular region

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 S46 Injury of muscle, fascia and tendon at shoulder and upper arm level applies to 216 codes
  • injury of muscle, fascia and tendon at elbow (S56.-)
  • sprain of joints and ligaments of shoulder girdle (S43.9)
From Block S40-S49 Injuries to the shoulder and upper arm applies to 2,730 codes
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 S46 Injury of muscle, fascia and tendon at shoulder and upper arm level applies to 216 codes
  • any associated open wound (S41.-)

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 S46 Injury of muscle, fascia and tendon at shoulder and upper arm level applies to 216 codes
  • The appropriate 7th character is to be added to each code from category S46
Values for category S46 Encounter: Initial, Subsequent, Sequela
  • Ainitial encounter this code
  • Dsubsequent encounter
  • 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 S46.129A, its category, or a range that includes it.

Excludes2 1

These codes carry an Excludes2 note naming S46.129A: its condition is not part of those codes, and both may be reported when the patient has both.

  • S43 Dislocation and sprain of joints and ligaments of shoulder girdle
    strain of muscle, fascia and tendon of shoulder and upper arm (S46.-) names S46.-, which includes this code

Clinical ClassificationClinical

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

CCSR INJ012
Open wounds to limbs, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Shoulder Injuries and Disorders

Your shoulder joint is composed of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone). Your shoulders are the most movable joints in your body. They can also be unstable because the ball of the upper arm is larger than the shoulder socket that holds it.

Read the full article at MedlinePlus

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

Convert S46.129A to ICD-9-CMHistory

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

ICD-9-CM
880.20 Opn wnd shouldr w tendon
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 S46.129AOverview

Is S46.129A a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report laceration of muscle, fascia and tendon of long head of biceps, unspecified arm, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What does the 7th character A in S46.129A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for laceration of muscle, fascia and tendon of long head of biceps, unspecified arm, such as an emergency visit or first evaluation.

What MS-DRG does S46.129A group to?

When laceration of muscle, fascia and tendon of long head of biceps, unspecified arm, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 564, 964, 965, 566, 565, 963, with relative weights from 0.7374 to 2.6361 depending on complications. Higher weights mean higher Medicare reimbursement.

Is S46.129A a CC or MCC?

CMS lists S46.129A as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 54 closely related codes in its exclusion list.

What is the ICD-9 equivalent of S46.129A?

Under the General Equivalence Mappings, laceration of muscle, fascia and tendon of long head of biceps, unspecified arm, initial encounter converts to ICD-9-CM 880.20 (opn wnd shouldr w tendon). The mapping is approximate, so confirm the match fits the documentation.