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S66.491 vs S66.492

S66.491 (Other specified injury of intrinsic muscle, fascia and tendon of right thumb at wrist and hand level) compared with S66.492 (Other specified injury of intrinsic muscle, fascia and tendon of left thumb at wrist and hand level), from the official CMS tabular data. S66.491 and S66.492 code the same condition on opposite sides.

Relationship

Review

Laterality relationship

S66.491
Right
Other specified injury of intrinsic muscle, fascia and tendon of right thumb at wrist and hand level
S66.492
Left
Other specified injury of intrinsic muscle, fascia and tendon of left thumb at wrist and hand level

Same condition; these differ only in which side is documented.

These codes share a category and title and differ only in the side affected. The documentation decides which applies, and a bilateral code is reported only where the code set provides one.

Source: ICD-10-CM tabular list (laterality variant derived from the code title)

Can these codes be reported together?

Same condition, opposite side. S66.491 and S66.492 name the same condition on opposite sides of the body.

Same category and title, differing only in which side is affected — the documentation decides which one applies, and a bilateral code is reported only where the code set provides one.

Side by side

S66.491Other specified injury of intrinsic muscle, fascia and tendon of right thumb at wrist and hand levelS66.492Other specified injury of intrinsic muscle, fascia and tendon of left thumb at wrist and hand level
Billing statusNon-billable header

Report instead: S66.491A, S66.491D, S66.491S

Non-billable header

Report instead: S66.492A, S66.492D, S66.492S

ClassificationS00-T88 — Injury, poisoning and certain other consequences of external causesS00-T88 — Injury, poisoning and certain other consequences of external causes
DefinitionOther specified injury of intrinsic muscle, fascia and tendon of right thumb at wrist and hand level is a non-billable ICD-10-CM category code (S66.491).Other specified injury of intrinsic muscle, fascia and tendon of left thumb at wrist and hand level is a non-billable ICD-10-CM category code (S66.492).
7th characterThe appropriate 7th character is to be added to each code from category S66The appropriate 7th character is to be added to each code from category S66

Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources