Diseases of the musculoskeletal system and connective tissue (M00–M99) ICD-10-CM
Chapter 13 of the ICD-10-CM classification spans codes M00–M99 and contains 8,270 diagnosis codes for diseases of the musculoskeletal system and connective tissue, of which 6,423 are billable. The chapter is organized into 20 sections listed below, each linking to its code ranges and individual codes.
Chapter Coding Notes
Note: Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition
Excludes2: 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)
Sections in This Chapter 20 ranges · 8,270 codes
The info icon previews the code ranges inside each row and its instructional notations from the official Tabular List.
About Chapter 13
Chapter 13 of the ICD-10-CM, covering codes M00–M99, categorizes diseases affecting the musculoskeletal system and connective tissue. These codes are used to identify disorders involving bones, joints, muscles, ligaments, and related soft tissues, including both inflammatory and non-inflammatory conditions.
This chapter includes a wide range of conditions such as arthritis, osteoporosis, muscular dystrophies, connective tissue diseases like lupus and scleroderma, and various deformities or injuries affecting the musculoskeletal framework. The codes help healthcare providers specify the type and location of musculoskeletal problems for accurate diagnosis, treatment planning, and medical reporting. Medical coders utilize this section to capture the complexity of bone and connective tissue diseases, ranging from acute infections to chronic degenerative disorders. Proper documentation under these codes supports effective communication in patient care and informs clinical decisions related to mobility and structural integrity.
Questions About This Page
How many codes are in the M00-M99 range?
The M00-M99 range contains 8,270 ICD-10-CM diagnosis codes in FY 2026. 6,423 of them are billable, and the rest are category headers that organize the chapter.
What conditions does M00-M99 cover?
The range covers diseases of the musculoskeletal system and connective tissue. The sections listed above break it into groups of related conditions, and each one links to its own page with the full code list.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
