ICD-10-CM 2027
ICD-10 code for muscle anomaly
From the official ICD-10-CM alphabetic index entry “Anomaly, anomalous (congenital) (unspecified type) › muscle”. Page updated September 29, 2026.
About coding muscle anomaly
The ICD-10-CM code for muscle anomaly is Q79.9 (Congenital malformation of musculoskeletal system, unspecified). The official index lists 1 more specific code, so check the documentation for details such as type, cause, site or severity before settling on Q79.9.
Within Q79, choose Q79.9 (Congenital malformation of musculoskeletal system, unspecified) only when documentation doesn't support a more specific option: congenital diaphragmatic hernia (Q79.0), other congenital malformations of diaphragm (Q79.1), Exomphalos (Q79.2), gastroschisis (Q79.3), prune belly syndrome (Q79.4), other congenital malformations of abdominal wall (Q79.5), Ehlers-Danlos syndromes (Q79.6) and other congenital malformations of musculoskeletal system (Q79.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 564 (Other Musculoskeletal System and Connective Tissue Diagnoses with MCC, relative weight 1.4908), DRG 565 (Other Musculoskeletal System and Connective Tissue Diagnoses with CC, relative weight 0.9783) and DRG 566 (Other Musculoskeletal System and Connective Tissue Diagnoses without CC/MCC, relative weight 0.7378), in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific muscle anomaly codes (official index)
- eyelid Q10.3 — Other congenital malformations of eyelid
Common questions about muscle anomaly ICD-10 codes
What is the ICD-10 code for muscle anomaly?
- Q79.9 — Congenital malformation of musculoskeletal system, unspecified. More specific codes apply when the documentation supports them: Q10.3.
What is the ICD-10 code for eyelid muscle anomaly?
- Q10.3 — Other congenital malformations of eyelid.
Is Q79.9 billable?
- Yes. Q79.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Q79.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Q79.9 as a principal diagnosis.
Is Q79.9 a CC or MCC?
- No. Q79.9 is neither a CC nor an MCC under MS-DRG v44.0.