ICD-10-CM · Other

M79.11

Pain localized to the muscles of mastication — primarily the masseter and temporalis — without joint involvement, classified under soft tissue disorders of the musculoskeletal system.

Verified May 8, 2026 · 6 sources ↓

Status
Billable
Chapter
13
Related CPT
7
Region
Other
Drawn from CDCICD10DataAAPCIcdcodesOstrowonline

Documentation tips

What should appear in the chart to support M79.11.

Source · Editorial brief grounded in 6 cited references ↓

  • Name the specific muscle(s) involved — masseter, temporalis, or pterygoid — rather than writing 'jaw pain' or 'facial pain.'
  • Explicitly document absence of TMJ joint involvement (no clicking, locking, or joint line tenderness) to justify a myogenous rather than articular code.
  • Record findings from palpation: location of tenderness, reproduction of familiar pain, and any referred pain pattern to distinguish localized myalgia from myofascial pain syndrome.
  • Note whether pain is provoked by mastication (chewing, clenching) to anchor it to the masticatory muscle group and support medical necessity.
  • If imaging (MRI, panoramic X-ray) was performed, document the result — normal joint space and intact condyle support a myogenous diagnosis over an articular one.

Related CPT procedures

Procedure codes commonly billed with M79.11. Linking the right diagnosis to the right procedure is what establishes medical necessity.

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

Common coding pitfalls

The recurring mistakes coders make with M79.11 and adjacent codes.

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

  • Coding M79.11 and M79.7 (fibromyalgia) together on the same claim violates the Excludes1 rule at the M79.1 category level — payers will reject or deny.
  • Defaulting to M79.10 (unspecified site) when the chart clearly identifies the masseter or temporalis — M79.11 is the correct specific code and M79.10 is likely to trigger a documentation query or downcoded reimbursement.
  • Using M79.11 for TMJ pain with confirmed joint pathology — articular temporomandibular disorders belong in the M26.6x range, not the myalgia subcategory.
  • Confusing M79.11 (mastication muscles) with M79.12 (auxiliary muscles of head and neck such as SCM and trapezius) — the clinical note must specify which muscle group is affected.
  • Applying M79.11 when myositis (M60.-) is the documented diagnosis — Excludes1 prohibits concurrent coding with any M60.- code.

Clinical context

Source · Editorial summary grounded in 6 cited references ↓

M79.11 applies when a patient presents with dull, aching muscle pain confined to the masticatory muscles (masseter, temporalis, medial and lateral pterygoids) and the clinical record explicitly excludes joint pathology. The key distinction from temporomandibular joint (TMJ) disorder is that this code covers myogenous pain — muscle origin — not articular pain. If imaging or clinical exam implicates the TMJ joint itself, look to the M26.6x range instead.

M79.11 was introduced in FY2019 (effective October 1, 2018) when the non-specific parent code M79.1 was converted to a non-billable parent and four site-specific child codes were added. Before that split, all myalgia mapped to a single unclassified code. Today, if the documented pain is in cervical or head muscles other than the masticators, use M79.12. If the site is identifiable but outside those regions, use M79.18. Reserve M79.10 only when localization is genuinely undocumented.

Two Excludes1 restrictions apply at the M79.1 category level: fibromyalgia (M79.7) and myositis (M60.-) cannot be coded on the same claim as M79.11. If the clinical picture points to widespread pain meeting fibromyalgia criteria, M79.7 displaces M79.11 entirely. Psychogenic muscle pain maps to F45.8 or F45.41, not here.

Sibling codes

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

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 6 cited references ↓

01Can M79.11 be used for TMJ pain?
Only if the pain is purely myogenous — documented as muscle tenderness without joint involvement. Confirmed TMJ articular pathology (disc displacement, joint degeneration) maps to M26.6x, not M79.11.
02What is the difference between M79.11 and M79.12?
M79.11 is restricted to the muscles of mastication (masseter, temporalis, pterygoids). M79.12 covers auxiliary muscles of the head and neck such as the sternocleidomastoid and trapezius. The clinical note must identify which muscle group is symptomatic.
03Why was M79.1 replaced, and does it still exist?
M79.1 was converted to a non-billable parent code in FY2019 when four site-specific child codes (M79.10–M79.18) were added. M79.1 alone will reject as non-specific; you must bill one of the four billable child codes.
04Can M79.11 and fibromyalgia (M79.7) be coded together?
No. The Excludes1 note at the M79.1 category level prohibits coding M79.11 and M79.7 on the same claim. If fibromyalgia criteria are met, M79.7 is the appropriate code and M79.11 should not be reported.
05Does M79.11 require a 7th character?
No. M-codes in Chapter 13 do not use 7th-character extensions. The 7th-character A/D/S convention applies to injury codes (S-codes), not musculoskeletal disorder codes.
06What MS-DRG does M79.11 fall into?
M79.11 groups to MS-DRG 555 (Signs and symptoms of musculoskeletal system and connective tissue with MCC) or 556 (without MCC), per MS-DRG v43.0.
07Is M79.11 appropriate when myositis is also documented?
No. The Excludes1 restriction at M79.1 prohibits concurrent coding with any myositis code in the M60.- range. If myositis is confirmed, code from M60.- and drop M79.11.

Mira AI Scribe

Mira captures the specific muscle name (masseter, temporalis, pterygoid), provocation by chewing or clenching, palpation tenderness findings, and explicit absence of TMJ joint signs from the encounter note. That detail locks in M79.11 over the unspecified M79.10, prevents a cross-code conflict with M79.7 or M60.-, and gives the payer clinical justification for any associated therapeutic procedures.

See how Mira captures M79.11 documentation

Related ICD-10 codes

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