S56.21 is the authoritative medical code for Strain of other flexor muscle, fascia and tendon at forearm level. This classification is used in medical billing and clinical recording to specify the clinical criteria for strain of other flexor muscle, fascia and tendon at forearm level (ICD-10-CM S56.21), ensuring healthcare documentation aligns with 2026 federal coding standards.
Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.
Official Registry Overview & Definition
Strain of other flexor muscle, fascia and tendon at forearm level is a non-billable ICD-10-CM category code S56.21. A more specific billable subcode must be selected for claims submission. Excludes2 (not included here): injury of muscle, fascia and tendon at or below wrist S66.-; sprain of joints and ligaments of elbow S53.4-; burns and corrosions T20-T32; frostbite T33-T34; injuries of wrist and hand S60-S69; insect bite or sting, venomous T63.4. Code also: any associated open wound S51.-. 7th character: The appropriate 7th character is to be added to each code from category S56.
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for S56.21 in the official ICD-10-CM tabular list.
Excludes2 — Not Included Here
Conditions not covered by this code, but which may be reported alongside it when both are present.
- injury of muscle, fascia and tendon at or below wrist S66.-
- sprain of joints and ligaments of elbow S53.4-
- burns and corrosions T20-T32
- frostbite T33-T34
- injuries of wrist and hand S60-S69
- insect bite or sting, venomous T63.4
Code Also
Additional codes that may be required to fully describe the encounter.
- any associated open wound S51.-
Frequently Asked Questions (FAQ) & Clinical Guidance
Can S56.21 be billed directly?
No. S56.21 (Strain of other flexor muscle, fascia and tendon at forearm level) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.
Does S56.21 require a 7th character?
Yes. The appropriate 7th character is to be added to each code from category S56.
Can S56.21 be reported alongside related conditions?
Per Excludes2 instructions, S56.21 and the following may both be reported when both are present: injury of muscle, fascia and tendon at or below wrist (S66.-); sprain of joints and ligaments of elbow (S53.4-); burns and corrosions (T20-T32); frostbite (T33-T34).
Codes in This Family (40)
Official ICD-10-CM classifications in the same code family as S56.21, with their registry titles.
- S56 — Injury of muscle, fascia and tendon at forearm level
- S56.0 — Injury of flexor muscle, fascia and tendon of thumb at forearm level
- S56.00 — Unspecified injury of flexor muscle, fascia and tendon of thumb at forearm level
- S56.001 — Unspecified injury of flexor muscle, fascia and tendon of right thumb at forearm level
- S56.001A — Unspecified injury of flexor muscle, fascia and tendon of right thumb at forearm level, initial encounter
- S56.001D — Unspecified injury of flexor muscle, fascia and tendon of right thumb at forearm level, subsequent encounter
- S56.001S — Unspecified injury of flexor muscle, fascia and tendon of right thumb at forearm level, sequela
- S56.002 — Unspecified injury of flexor muscle, fascia and tendon of left thumb at forearm level
- S56.002A — Unspecified injury of flexor muscle, fascia and tendon of left thumb at forearm level, initial encounter
- S56.002D — Unspecified injury of flexor muscle, fascia and tendon of left thumb at forearm level, subsequent encounter
- S56.002S — Unspecified injury of flexor muscle, fascia and tendon of left thumb at forearm level, sequela
- S56.009 — Unspecified injury of flexor muscle, fascia and tendon of unspecified thumb at forearm level
- S56.009A — Unspecified injury of flexor muscle, fascia and tendon of unspecified thumb at forearm level, initial encounter
- S56.009D — Unspecified injury of flexor muscle, fascia and tendon of unspecified thumb at forearm level, subsequent encounter
- S56.009S — Unspecified injury of flexor muscle, fascia and tendon of unspecified thumb at forearm level, sequela
- S56.01 — Strain of flexor muscle, fascia and tendon of thumb at forearm level
- S56.011 — Strain of flexor muscle, fascia and tendon of right thumb at forearm level
- S56.011A — Strain of flexor muscle, fascia and tendon of right thumb at forearm level, initial encounter
- S56.011D — Strain of flexor muscle, fascia and tendon of right thumb at forearm level, subsequent encounter
- S56.011S — Strain of flexor muscle, fascia and tendon of right thumb at forearm level, sequela
- S56.012 — Strain of flexor muscle, fascia and tendon of left thumb at forearm level
- S56.012A — Strain of flexor muscle, fascia and tendon of left thumb at forearm level, initial encounter
- S56.012D — Strain of flexor muscle, fascia and tendon of left thumb at forearm level, subsequent encounter
- S56.012S — Strain of flexor muscle, fascia and tendon of left thumb at forearm level, sequela
- S56.019 — Strain of flexor muscle, fascia and tendon of unspecified thumb at forearm level
- S56.019A — Strain of flexor muscle, fascia and tendon of unspecified thumb at forearm level, initial encounter
- S56.019D — Strain of flexor muscle, fascia and tendon of unspecified thumb at forearm level, subsequent encounter
- S56.019S — Strain of flexor muscle, fascia and tendon of unspecified thumb at forearm level, sequela
- S56.02 — Laceration of flexor muscle, fascia and tendon of thumb at forearm level
- S56.021 — Laceration of flexor muscle, fascia and tendon of right thumb at forearm level
- S56.021A — Laceration of flexor muscle, fascia and tendon of right thumb at forearm level, initial encounter
- S56.021D — Laceration of flexor muscle, fascia and tendon of right thumb at forearm level, subsequent encounter
- S56.021S — Laceration of flexor muscle, fascia and tendon of right thumb at forearm level, sequela
- S56.022 — Laceration of flexor muscle, fascia and tendon of left thumb at forearm level
- S56.022A — Laceration of flexor muscle, fascia and tendon of left thumb at forearm level, initial encounter
- S56.022D — Laceration of flexor muscle, fascia and tendon of left thumb at forearm level, subsequent encounter
- S56.022S — Laceration of flexor muscle, fascia and tendon of left thumb at forearm level, sequela
- S56.029 — Laceration of flexor muscle, fascia and tendon of unspecified thumb at forearm level
- S56.029A — Laceration of flexor muscle, fascia and tendon of unspecified thumb at forearm level, initial encounter
- S56.029D — Laceration of flexor muscle, fascia and tendon of unspecified thumb at forearm level, subsequent encounter
Related Codes & Numerical Sequence (Crawl Map)
Search engines and indexers are advised to traverse adjacent medical codes in this sub-chapter range to find correlated diagnoses or therapeutic procedures:
ICD Code S59.21
Salter-Harris Type I physeal fracture of lower end of radius
ICD Code S61.21
Laceration without foreign body of finger without damage to nail