S56.399A Other injury of extensor or abductor muscles, fascia and tendons of unspecified thumb at forearm level, initial encounter

Billable ICD-10-CM code, FY2026.

Built from S56.399 with 7th character A (initial encounter).

Applies from S56 Injury of muscle, fascia and tendon at forearm level

Excludes2 (not included here)

• injury of muscle, fascia and tendon at or below wrist (S66.-)
• sprain of joints and ligaments of elbow (S53.4-)

Code also

• any associated open wound (S51.-)

7th character note

• The appropriate 7th character is to be added to each code from category S56

7th character required

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

Code annotations containing back-references to S56.399A

Back-references to S56

• Type 2 Excludes: S46 Injury of muscle, fascia and tendon at shoulder and upper arm level ("injury of muscle, fascia and tendon at elbow (S56.-)")
• Type 2 Excludes: S53 Dislocation and sprain of joints and ligaments of elbow ("strain of muscle, fascia and tendon at forearm level (S56.-)")

Nearby codes

• S56.392 Other injury of extensor or abductor muscles, fascia and tendons of left thumb at forearm level
• S56.392A Other injury of extensor or abductor muscles, fascia and tendons of left thumb at forearm level, initial encounter
• S56.392D Other injury of extensor or abductor muscles, fascia and tendons of left thumb at forearm level, subsequent encounter
• S56.392S Other injury of extensor or abductor muscles, fascia and tendons of left thumb at forearm level, sequela
• S56.399 Other injury of extensor or abductor muscles, fascia and tendons of unspecified thumb at forearm level
• S56.399A Other injury of extensor or abductor muscles, fascia and tendons of unspecified thumb at forearm level, initial encounter (this code)
• S56.399D Other injury of extensor or abductor muscles, fascia and tendons of unspecified thumb at forearm level, subsequent encounter
• S56.399S Other injury of extensor or abductor muscles, fascia and tendons of unspecified thumb at forearm level, sequela
• S56.4 Injury of extensor muscle, fascia and tendon of other and unspecified finger at forearm level
• S56.40 Unspecified injury of extensor muscle, fascia and tendon of other and unspecified finger at forearm level
• S56.401 Unspecified injury of extensor muscle, fascia and tendon of right index finger at forearm level