2026 ICD-10-CM Diagnosis Code S41.109AUnspecified open wound of unspecified upper arm, initial encounter

ICD-10-CM Codes›S00–T88›S40-S49›S41

ICD-10-CM S41.109A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S41.109A is a billable ICD-10-CM diagnosis code for unspecified open wound of unspecified upper 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 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 604 through 605, 963 through 965. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Open wounds to limbs, initial encounter.

Code Identity

ICD-10-CM Code
S41.109A
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified open wound of unspecified upper arm, initial encounter
Short Description
Unspecified open wound of unspecified upper arm, init encntr
Parent Code
S41.109
Unspecified open wound of unspecified upper arm

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS40-S49Injuries to the shoulder and upper arm
CategoryS41Open wound of shoulder and upper arm
This CodeS41.109AUnspecified open wound of unspecified upper arm, initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Crushing injury of axillary region
  • Crushing injury of upper arm
  • Elbow fracture - open
  • Fracture of lesser tuberosity of humerus
  • Fracture of the lateral humeral epicondyle
  • Fracture of the medial humeral epicondyle
  • Glass in axilla
  • Glass in shoulder
  • Glass in upper arm
  • Injury of axillary artery
  • Injury of axillary vein
  • Injury of brachial artery
  • Injury of brachial plexus trunk
  • Injury of musculocutaneous nerve
  • Multiple fractures of humerus
  • Multiple open dislocations of arm
  • Multiple open fractures of distal humerus
  • Multiple open wounds of shoulder
  • Multiple open wounds of shoulder and upper arm
  • Multiple open wounds of upper arm
  • Musculocutaneous nerve lesion
  • Open crush injury, axilla
  • Open crush injury, shoulder area
  • Open crush injury, upper arm
  • Open fracture distal humerus, bicondylar
  • Open fracture distal humerus, lateral epicondyle
  • Open fracture of condyle of humerus
  • Open fracture of humerus, upper epiphysis
  • Open fracture of lesser tuberosity of humerus
  • Open fracture of lower epiphysis of humerus
  • Open fracture of medial epicondyle of humerus
  • Open injury, axillary artery
  • Open injury, axillary vein
  • Open injury, brachial artery
  • Open injury, brachial plexus, lower roots
  • Open injury, musculocutaneous nerve
  • Open multiple fractures of clavicle and/or scapula and/or humerus
  • Open supracondylar fracture of humerus
  • Open transcondylar fracture of distal humerus
  • Open wound of axillary region
  • Open wound of upper arm
  • Pellet wound of axilla
  • Pellet wound of shoulder
  • Supracondylar fracture of humerus
  • Transcondylar fracture of distal humerus
  • Wound of axillary region

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Open wound of shoulder and upper arm (S41). 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 2026, published by CMS and the National Center for Health Statistics.

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

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 S41.109A to ICD-9-CMHistory

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

ICD-9-CM
880.03 Open wound of upper arm
Approximate The match is approximate rather than exact.
ICD-9-CM
880.09 Mult open wound shoulder
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 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About S41.109AOverview

Is S41.109A (Unspecified open wound of unspecified upper arm) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unspecified open wound of unspecified upper arm, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in S41.109A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for unspecified open wound of unspecified upper arm, such as an emergency visit or first evaluation.

What MS-DRG does S41.109A group to?

When unspecified open wound of unspecified upper arm, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 604, 605, 963, 964, 965, with relative weights from 0.9160 to 2.7338 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of S41.109A?

Under the General Equivalence Mappings, unspecified open wound of unspecified upper arm, initial encounter converts to ICD-9-CM 880.03 (open wound of upper arm) and 880.09 (mult open wound shoulder). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.