MCMedicalCodingSoftware
S66.318

S66.318: Strain of extensor muscle, fascia and tendon of other finger at wrist and hand level

Non-billable headerICD-10-CM

S66.318 is a non-billable header ICD-10-CM code for strain of extensor muscle, fascia and tendon of other finger at wrist and hand level. It cannot be billed on its own: choose one of the more specific child codes below. This code also requires a 7th character before it is complete.

This code requires a 7th character

The appropriate 7th character is to be added to each code from category S66

A
initial encounter
D
subsequent encounter
S
sequela

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Strain of extensor muscle, fascia and tendon of specified finger with unspecified laterality at wrist and hand level

Excludes2 inherited from the categories above S66.318

Not part of this code, but both may be coded when both are present.

Written on S66.3: Injury of extensor muscle, fascia and tendon of other and unspecified finger at wrist and hand level

  • Injury of extensor muscle, fascia and tendon of thumb at wrist and hand level (S66.2-)

Written on S66: Injury of muscle, fascia and tendon at wrist and hand level

  • sprain of joints and ligaments of wrist and hand (S63.-)

Risk adjustment

No CMS-HCC V28 category: this code does not change a RAF score.

Code history

Unchanged in every release from FY2024 to FY2027.

Code to one of these instead S66.318

3 child codes. Green means billable.

Other codes under S66.31

ICD-10-CMFY2027· effective October 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release: see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.