Alphabetic Index FY2027

S66.59

Other injury of intrinsic muscle, fascia and tendon of other and unspecified finger at wrist and hand level

FY2027Chapter 19: Injury, poisoning and certain other consequences of external causes/S60–S69 Injuries to the wrist, hand and fingers

Non-billable headerNot valid on its own. Use one of the more specific codes under it.

S66.59 is a non-billable ICD-10-CM code header for other injury of intrinsic muscle, fascia and tendon of other and unspecified finger at wrist and hand level. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are S66.590 Other injury of intrinsic muscle, fascia and tendon of right index finger at wrist and hand level; S66.591 Other injury of intrinsic muscle, fascia and tendon of left index finger at wrist and hand level; S66.592 Other injury of intrinsic muscle, fascia and tendon of right middle finger at wrist and hand level; S66.593 Other injury of intrinsic muscle, fascia and tendon of left middle finger at wrist and hand level and 6 more. Its coding notes include a Use additional code instruction, a Code also instruction and 7 Excludes2 entries.

7th characters

Every code below needs one of these (defined at S66).

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

  • Ainitial encounter
  • Dsubsequent encounter
  • Ssequela

Guidelines tips

From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.

The 7th character depends on whether the patient is in active treatment, not on who sees the patient. An aftercare Z code is not used for injury aftercare.

Guidelines I.C.19.aInjuries: application of 7th charactersRead the official text

Each injury gets its own code unless a combination code exists, with the most serious injury first. Superficial injuries at the same site as a more severe injury are not coded. Injuries during medical care are coded as complications.

Guidelines I.C.19.bCoding of injuriesRead the official text

Use additional code

Add the listed code as a secondary code, if known.

Also from chapter/block level (1 note)
Inherited from Chapter 19 Injury, poisoning and certain other consequences of external causes
  • code to identify any retained foreign body, if applicable (Z18.-)

Code also

Two codes may be needed to describe the condition. This note gives no sequencing order.

Inherited from S66 Injury of muscle, fascia and tendon at wrist and hand level
  • any associated open wound (S61.-)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Inherited from 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-)
Inherited from S66 Injury of muscle, fascia and tendon at wrist and hand level
  • sprain of joints and ligaments of wrist and hand (S63.-)
Also from chapter/block level (5 notes)
Inherited from S60–S69 Injuries to the wrist, hand and fingers
Inherited from Chapter 19 Injury, poisoning and certain other consequences of external causes
  • birth trauma (P10-P15)
  • obstetric trauma (O70-O71)

Notes

Also from chapter/block level (2 notes)
Inherited from Chapter 19 Injury, poisoning and certain other consequences of external causes
  • Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
  • The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 4 entries

More specific codes under S66.59 10