S66.421A Laceration of intrinsic muscle, fascia and tendon of right thumb at wrist and hand level, initial encounter

Billable ICD-10-CM code, FY2026.

Built from S66.421 with 7th character A (initial encounter).

Applies from S66 Injury of muscle, fascia and tendon at wrist and hand level

Excludes2 (not included here)

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

Code also

• any associated open wound (S61.-)

7th character note

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

7th character required

• A — initial encounter
• D — subsequent encounter
• S — sequela

Code annotations containing back-references to S66.421A

Back-references to S66.4

• Type 2 Excludes: S66.5 Injury of intrinsic muscle, fascia and tendon of other and unspecified finger at wrist and hand level ("injury of intrinsic muscle, fascia and tendon of thumb at wrist and hand level (S66.4-)")

Back-references to S66

• Type 2 Excludes: S56 Injury of muscle, fascia and tendon at forearm level ("injury of muscle, fascia and tendon at or below wrist (S66.-)")
• Type 2 Excludes: S63 Dislocation and sprain of joints and ligaments at wrist and hand level ("strain of muscle, fascia and tendon of wrist and hand (S66.-)")

Nearby codes

• S66.419A Strain of intrinsic muscle, fascia and tendon of unspecified thumb at wrist and hand level, initial encounter
• S66.419D Strain of intrinsic muscle, fascia and tendon of unspecified thumb at wrist and hand level, subsequent encounter
• S66.419S Strain of intrinsic muscle, fascia and tendon of unspecified thumb at wrist and hand level, sequela
• S66.42 Laceration of intrinsic muscle, fascia and tendon of thumb at wrist and hand level
• S66.421 Laceration of intrinsic muscle, fascia and tendon of right thumb at wrist and hand level
• S66.421A Laceration of intrinsic muscle, fascia and tendon of right thumb at wrist and hand level, initial encounter (this code)
• S66.421D Laceration of intrinsic muscle, fascia and tendon of right thumb at wrist and hand level, subsequent encounter
• S66.421S Laceration of intrinsic muscle, fascia and tendon of right thumb at wrist and hand level, sequela
• S66.422 Laceration of intrinsic muscle, fascia and tendon of left thumb at wrist and hand level
• S66.422A Laceration of intrinsic muscle, fascia and tendon of left thumb at wrist and hand level, initial encounter
• S66.422D Laceration of intrinsic muscle, fascia and tendon of left thumb at wrist and hand level, subsequent encounter