M66.221 — Spontaneous rupture of extensor tendons, right upper arm
Is M66.221 billable?
Yes — M66.221 is billable for FY2027. M66.221 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. M66.221 may be submitted for encounters from October 1, 2026 through September 30, 2027.
M66.221 at a glance
| Code | M66.221 |
|---|---|
| Description | Spontaneous rupture of extensor tendons, right upper arm |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does M66.221 group to?
M66.221 sits in MDC 08 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 557Tendonitis, Myositis and Bursitis with MCCmedical
- 558Tendonitis, Myositis and Bursitis without MCCmedical
How is M66.221 listed in the Alphabetic Index?
The Alphabetic Index lists these routes under M66.22, the nearest indexed parent of M66.221. Use them to find the family, then select the specific code.
- Rupture, ruptured › tendon › nontraumatic › extensor › upper arm
Excludes2 — not included here — inherited from Chapter 13
The conditions below are not part of M66.221, but a patient may have both at the same time. When documentation supports it, M66.221 and the excluded code may both be reported.
- 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)
Excludes2 — not included here — inherited from M66
The conditions below are not part of M66.221, but a patient may have both at the same time. When documentation supports it, M66.221 and the excluded code may both be reported.
- rotator cuff syndrome (M75.1-)
- rupture where an abnormal force is applied to normal tissue - see injury of tendon by body region
How long has M66.221 existed?
M66.221 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.