2027 ICD-10-CM Diagnosis Code M79.12Myalgia of auxiliary muscles, head and neck

ICD-10-CM Codes›M00–M99›M70-M79›M79

ICD-10-CM M79.12
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

M79.12 is a billable ICD-10-CM diagnosis code for myalgia of auxiliary muscles, head and neck. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 555 through 556. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Musculoskeletal pain, not low back pain.

Code Identity

ICD-10-CM Code
M79.12
Billable Status
Yes — Valid for Submission
Code Describes
Myalgia of auxiliary muscles, head and neck
Short Description
Myalgia of auxiliary muscles, head and neck
Same as the full description in the CMS dataset.
Parent Code
M79.1
Myalgia

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM70-M79Other soft tissue disorders
CategoryM79Other and unspecified soft tissue disorders, not elsewhere classified
This CodeM79.12Myalgia of auxiliary muscles, head and neck

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to M79.12: its own notes plus those printed at M79.1, M79, and Chapter 13. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From M79.1 Myalgia applies to 4 codes
From M79 Other and unspecified soft tissue disorders, not elsewhere classified applies to 52 codes
  • psychogenic rheumatism (F45.8)
  • soft tissue pain, psychogenic (F45.41)

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 Chapter 13 (M00-M99) Diseases of the musculoskeletal system and connective tissue applies to 6,687 codes
  • arthropathic psoriasis (L40.5-)
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • compartment syndrome (traumatic) (T79.A-)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Notes

General instructions on how these codes are used.

From Chapter 13 (M00-M99) Diseases of the musculoskeletal system and connective tissue applies to 6,687 codes
  • Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name M79.12, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming M79.12: they are not reported together with it, unless the two conditions are unrelated.

  • M62 Other disorders of muscle
    myalgia (M79.1-) names M79.1-, which includes this code

Excludes2 1

These codes carry an Excludes2 note naming M79.12: its condition is not part of those codes, and both may be reported when the patient has both.

  • G89 Pain, not elsewhere classified
    myalgia (M79.1-) names M79.1-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

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

CCSR MUS010
Musculoskeletal pain, not low back pain
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Myalgia

    painful sensation in the muscles.

Patient EducationClinical

Muscle Disorders

Your muscles help you move and help your body work. Different types of muscles have different jobs. There are many problems that can affect muscles. Muscle disorders can cause weakness, pain or even paralysis.

Read the full article at MedlinePlus

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

Code History & ChangesHistory

Replacement M79.12 replaces the following previously assigned code(s):

  • M79.1 - Myalgia
FY 2019AddedAdded to the ICD-10-CM code setEffective October 1, 2018.
FY 2020–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About M79.12Overview

What is the ICD-10 code for myalgia of auxiliary muscles, head and neck?

The ICD-10-CM code for myalgia of auxiliary muscles, head and neck is M79.12 (sometimes written as M7912). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is M79.12 (Myalgia) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report myalgia of auxiliary muscles, head and neck on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does M79.12 group to?

When myalgia of auxiliary muscles, head and neck is the principal diagnosis on an inpatient stay, it groups to MS-DRG 555, 556, with relative weights from 0.8210 to 1.2908 depending on complications. Higher weights mean higher Medicare reimbursement.

Can M79.12 be reported with M79.7?

Not as a rule. The Excludes1 note at M79.1, which applies to M79.12, lists "fibromyalgia (M79.7)". 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).