2027 ICD-10-CM Diagnosis Code S04.71XAInjury of accessory nerve, right side, initial encounter
ICD-10-CM Codes›S00–T88›S00-S09›S04
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- 7th Character A — Initial Encounter
- Not Chronic
S04.71XA is a billable ICD-10-CM diagnosis code for injury of accessory nerve, right side, 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 73 through 74, 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 10 closely related codes. Coders also document this condition as injury of accessory nerve. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Injury to nerves, muscles and tendons, initial encounter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Injury of accessory nerve
- Injury of right accessory nerve
- Right accessory neuropathy
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Injury of cranial nerve (S04). 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 S04.71XA: its own notes plus those printed at S04, block S00-S09, 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.
- injuries of ear
- injuries of eye
- injuries of face [any part]
- injuries of gum
- injuries of jaw
- injuries of oral cavity
- injuries of palate
- injuries of periocular area
- injuries of scalp
- injuries of temporomandibular joint area
- injuries of tongue
- injuries of tooth
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.
- burns and corrosions (T20-T32)
- effects of foreign body in ear (T16)
- effects of foreign body in larynx (T17.3)
- effects of foreign body in mouth NOS (T18.0)
- effects of foreign body in nose (T17.0-T17.1)
- effects of foreign body in pharynx (T17.2)
- effects of foreign body on external eye (T15.-)
- frostbite (T33-T34)
- insect bite or sting, venomous (T63.4)
Code First
The underlying condition named in the note is sequenced before this code.
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.
- for any associated infection
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 S04
- 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 S04.71XA, its category, or a range that includes it.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Neuromuscular Disorders
Neuromuscular disorders affect your neuromuscular system. They can cause problems with:
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Convert S04.71XA to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S04.71XAOverview
What is the ICD-10 code for injury of accessory nerve, right side, initial encounter?
The ICD-10-CM code for injury of accessory nerve, right side, initial encounter is S04.71XA (sometimes written as S0471XA). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is S04.71XA (Injury of accessory nerve, right side) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report injury of accessory nerve, right side, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character A in S04.71XA mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for injury of accessory nerve, right side, such as an emergency visit or first evaluation.
What MS-DRG does S04.71XA group to?
When injury of accessory nerve, right side, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 964, 965, 74, 73, 963, with relative weights from 1.0054 to 2.6361 depending on complications. Higher weights mean higher Medicare reimbursement.
Is S04.71XA a CC or MCC?
CMS lists S04.71XA 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 10 closely related codes in its exclusion list.
