Is ICD-10-CM code M77 billable?

No, M77 (Other enthesopathies) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code M77 belong to?

M77 belongs to Chapter 13 of the ICD-10-CM tabular list: M00–M99 (Diseases of the Musculoskeletal System and Connective Tissue).

M77Not billable, use a more specific code below

Other enthesopathies

In Other soft tissue disorders (M70-M79), chapter 13: Diseases of the Musculoskeletal System and Connective Tissue

20 billable codes under M77: none are a CC or MCC; none map to an HCC.

Instructional notes

Excludes1: not coded here, use a different code

bursitis NOS (M71.9-)

Excludes2: not included here, code separately if applicable

bursitis due to use, overuse and pressure (M70.-)
osteophyte (M25.7)
spinal enthesopathy (M46.0-)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Covers site and laterality, acute injury versus chronic musculoskeletal conditions, 7th characters for pathologic fractures, osteoporosis with or without current fracture, and multisystem inflammatory syndrome.

Site and laterality (page 60)
Acute traumatic versus chronic or recurrent musculoskeletal conditions (page 61)
Coding of Pathologic Fractures (page 61)
Osteoporosis (page 61)
Multisystem Inflammatory Syndrome (page 62)

Read Section I.C.13 (page 60)

All codes under M77

M77 can't be used on a claim. Pick a billable code below; grey headings group them.

M77 MS-DRGs

As the principal diagnosis, the billable codes under M77 group to MS-DRG 557, 558, 564, 565, or 566 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

DRG 557 Tendonitis, Myositis and Bursitis with MCC (17 of 20 codes)
DRG 558 Tendonitis, Myositis and Bursitis without MCC (17 of 20 codes)
DRG 564 Other Musculoskeletal System and Connective Tissue Diagnoses with MCC (3 of 20 codes)
DRG 565 Other Musculoskeletal System and Connective Tissue Diagnoses with CC (3 of 20 codes)
DRG 566 Other Musculoskeletal System and Connective Tissue Diagnoses without CC/MCC (3 of 20 codes)

Other codes that refer to M77

Notes on these codes point to M77.

M65.2 Excludes1: tendinitis as classified in M75-M77
M70 Excludes2: enthesopathies (M76-M77)
M71 Excludes1: enthesopathies (M76-M77)

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

Connective Tissue Disorders

Your connective tissue supports many different parts of your body, such as your skin, eyes, and heart. It is like a "cellular glue" that gives your body parts their shape and helps keep them strong. It also helps some of your tissues do their work. It is made of many kinds of proteins. Cartilage and fat are types of connective tissue.

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.