ICD-10-CM · Spine

M79.12

Muscle pain localized to the auxiliary (accessory) muscles of the head and neck region, such as the trapezius and sternocleidomastoid, without joint involvement.

Verified May 8, 2026 · 5 sources ↓

Status: Billable
Chapter: 13
Related CPT: 10
Region: Spine

Drawn from CDCICD10DataAAPCIcdcodesNIH

Documentation tips

What should appear in the chart to support M79.12.

Source · Editorial brief grounded in 5 cited references ↓

Name the specific muscle(s) involved — trapezius, sternocleidomastoid, scalenes, or other auxiliary head/neck muscles — rather than documenting only 'neck pain' or 'muscle aches.'
Record palpation findings: tenderness on exam, trigger points, or muscle guarding localizing to the auxiliary head/neck musculature.
Document that joint structures are not the primary pain source to support a soft-tissue myalgia code over a cervical or articular diagnosis.
Note any functional limitation, such as restricted or painful rotation of the head, to support medical necessity for associated therapy codes.
If fibromyalgia or myositis is on the differential, document clinical reasoning for ruling those out before assigning M79.12.

Related CPT procedures

Procedure codes commonly billed with M79.12. Linking the right diagnosis to the right procedure is what establishes medical necessity.

Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis

97110 $29.06

Therapeutic exercise billed per 15-minute unit, targeting strength, endurance, range of motion, or flexibility with direct one-on-one patient contact.

97140 $27.72

Skilled, hands-on manual therapy techniques — including joint mobilization/manipulation, manual lymphatic drainage, and manual traction — applied to one or more body regions, billed per 15-minute unit.

20552 $51.77

Injection(s) into one or two muscles for single or multiple trigger points at a single session.

20553 $59.79

Injection(s) into trigger points spanning three or more muscles during a single session

99213 $95.19

Established patient office or outpatient visit requiring 20–29 minutes of total time or low-complexity medical decision-making.

99214 $135.61

Office visit for an established patient requiring moderate-complexity medical decision making (MDM), or 30–39 minutes of total provider time on the date of service.

72040 $39.75

Radiologic examination of the cervical spine capturing two or three views (e.g., AP, lateral, oblique).

97012 View procedure details

97014 View procedure details

97530 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M79.12 and adjacent codes.

Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓

Using M79.12 for generic 'neck pain' — if the provider documents pain in the cervical spine or neck without specifying muscle involvement, cervicalgia (M54.2) is the correct code, not M79.12.
Upcoding from M79.10 (unspecified site) without adequate documentation — the medical record must explicitly localize pain to auxiliary head/neck muscles before stepping up to M79.12.
Coding M79.12 alongside fibromyalgia (M79.7) when fibromyalgia is the established diagnosis — fibromyalgia excludes site-specific myalgia codes for the same encounter unless a distinct localized condition is separately documented.
Failing to distinguish M79.12 from M79.11 — M79.11 is reserved for mastication muscle pain (masseter, temporalis); M79.12 covers the auxiliary/accessory muscles of the head and neck outside the jaw.
Billing M79.12 without supporting clinical findings when paired with injection CPT codes (e.g., 20552/20553) — payers may audit for documented trigger point identification in the auxiliary muscle group.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

M79.12 captures myalgia confined to the auxiliary muscles of the head and neck — specifically muscles like the trapezius and sternocleidomastoid that support movement and posture in that region. Use it when the provider documents palpable muscle tenderness, stiffness with head rotation, or pain in these named muscle groups, and joint involvement has been ruled out or is not the primary driver. It does not cover jaw or mastication muscle pain (M79.11) or generalized/unlocalized muscle pain (M79.10).

This code became effective October 1, 2018 (FY2019) when ICD-10-CM retired the nonspecific parent M79.1 (Myalgia) and replaced it with site-specific subcodes. Before assigning M79.12, confirm the documentation explicitly names or clinically localizes pain to auxiliary head and neck muscles. If the note says only 'neck pain,' consider cervicalgia (M54.2) instead — M79.12 requires the complaint to be muscular, not spinal or articular.

Exclude fibromyalgia (M79.7) and myositis (M60.-) before coding here. Fibromyalgia involves widespread pain with specific tender-point criteria; myositis implies inflammatory or infectious muscle pathology. M79.12 is appropriate for musculoskeletal soft-tissue muscle pain in the head/neck auxiliary group without those features.

Sibling codes

Other billable codes under M79.1 (laterality / anatomic variants).

M79.10

Myalgia, unspecified site

M79.11

Myalgia of mastication muscle

M79.18

Myalgia, other site

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 5 cited references ↓

01What muscles does M79.12 cover?

M79.12 applies to the auxiliary (accessory) muscles of the head and neck, most commonly the trapezius and sternocleidomastoid. It does not cover the mastication muscles (masseter, temporalis) — those fall under M79.11.

02When should I use M54.2 (cervicalgia) instead of M79.12?

Use M54.2 when the documented complaint is cervical spine pain or neck pain without explicit localization to a named auxiliary muscle. M79.12 requires the provider to identify the pain as muscular and in the auxiliary head/neck muscle group specifically.

03Can M79.12 and fibromyalgia (M79.7) be coded together?

Only if the documentation clearly supports a distinct localized myalgia separate from the fibromyalgia diagnosis. When fibromyalgia accounts for the head/neck muscle pain, M79.7 is the primary code and M79.12 should not be added for the same complaint.

04Is M79.12 valid for trigger point injection billing (CPT 20552/20553)?

Yes, M79.12 is an appropriate supporting diagnosis for trigger point injections into auxiliary head and neck muscles. Documentation must identify the specific muscle(s) injected and confirm palpable trigger point findings to withstand audit.

05What changed when M79.12 was introduced in FY2019?

Before October 1, 2018, all myalgia was reported under the single nonspecific code M79.1. FY2019 retired M79.1 and replaced it with four site-specific subcodes (M79.10, M79.11, M79.12, M79.18), requiring coders to document and select based on the location of muscle pain.

06Does M79.12 require laterality?

No. M79.12 has no laterality substructure in the ICD-10-CM code set. The code covers auxiliary head and neck muscles without distinguishing right from left. Document side in the clinical note for clinical accuracy, but no additional code digit is required.

07Can M79.12 be used for myofascial pain syndrome of the neck?

M79.12 is frequently assigned for myofascial pain presentations in the trapezius or sternocleidomastoid when the provider documents muscle tenderness and trigger points. There is no dedicated ICD-10-CM code for myofascial pain syndrome; M79.12 is the closest site-specific code for this region when myositis and fibromyalgia are excluded.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

01CDC ICD-10-CM Tabular List 2026 (effective Oct 1, 2025)
02
icd10data.com
https://www.icd10data.com/ICD10CM/Codes/M00-M99/M70-M79/M79-/M79.12
03
aapc.com
https://www.aapc.com/codes/coding-newsletters/my-orthopedic-coding-alert/icd-10-cm-update-code-set-for-2019-includes-expanded-myalgia-options-158113-article
04
icdcodes.ai
https://icdcodes.ai/diagnosis/myalgia/documentation
05
ncbi.nlm.nih.gov
https://www.ncbi.nlm.nih.gov/books/NBK499882/

Mira AI Scribe

Mira captures the specific muscle group named by the provider (trapezius, sternocleidomastoid, etc.), palpation findings such as tenderness or trigger points, functional deficits like restricted head rotation, and explicit absence of joint involvement. This prevents downcoding to M79.10 (unspecified site) or miscoding as cervicalgia (M54.2), both of which can trigger payer specificity edits or reduce reimbursement for associated therapy and injection procedures.

See how Mira captures M79.12 documentation