ICD-10-CM Code S66.10

Unspecified injury of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level

Version 2021 Non-Billable Code

Not Valid for Submission

S66.10 is a "header" nonspecific and non-billable code code, consider using a code with a higher level of specificity for a diagnosis of unspecified injury of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level. The code is NOT valid for the year 2021 for the submission of HIPAA-covered transactions.

ICD-10:S66.10
Short Description:Unsp inj flexor musc/fasc/tend and unsp finger at wrs/hnd lv
Long Description:Unspecified injury of flexor muscle, fascia and tendon of other and unspecified finger at wrist and hand level

Consider the following ICD-10 codes with a higher level of specificity:

  • S66.100 - Unspecified injury of flexor muscle, fascia and tendon of right index finger at wrist and hand level
  • S66.100A - Unspecified injury of flexor muscle, fascia and tendon of right index finger at wrist and hand level, initial encounter
  • S66.100D - Unspecified injury of flexor muscle, fascia and tendon of right index finger at wrist and hand level, subsequent encounter
  • S66.100S - Unspecified injury of flexor muscle, fascia and tendon of right index finger at wrist and hand level, sequela
  • S66.101 - Unspecified injury of flexor muscle, fascia and tendon of left index finger at wrist and hand level
  • S66.101A - Unspecified injury of flexor muscle, fascia and tendon of left index finger at wrist and hand level, initial encounter
  • S66.101D - Unspecified injury of flexor muscle, fascia and tendon of left index finger at wrist and hand level, subsequent encounter
  • S66.101S - Unspecified injury of flexor muscle, fascia and tendon of left index finger at wrist and hand level, sequela
  • S66.102 - Unspecified injury of flexor muscle, fascia and tendon of right middle finger at wrist and hand level
  • S66.102A - Unspecified injury of flexor muscle, fascia and tendon of right middle finger at wrist and hand level, initial encounter
  • S66.102D - Unspecified injury of flexor muscle, fascia and tendon of right middle finger at wrist and hand level, subsequent encounter
  • S66.102S - Unspecified injury of flexor muscle, fascia and tendon of right middle finger at wrist and hand level, sequela
  • S66.103 - Unspecified injury of flexor muscle, fascia and tendon of left middle finger at wrist and hand level
  • S66.103A - Unspecified injury of flexor muscle, fascia and tendon of left middle finger at wrist and hand level, initial encounter
  • S66.103D - Unspecified injury of flexor muscle, fascia and tendon of left middle finger at wrist and hand level, subsequent encounter
  • S66.103S - Unspecified injury of flexor muscle, fascia and tendon of left middle finger at wrist and hand level, sequela
  • S66.104 - Unspecified injury of flexor muscle, fascia and tendon of right ring finger at wrist and hand level
  • S66.104A - Unspecified injury of flexor muscle, fascia and tendon of right ring finger at wrist and hand level, initial encounter
  • S66.104D - Unspecified injury of flexor muscle, fascia and tendon of right ring finger at wrist and hand level, subsequent encounter
  • S66.104S - Unspecified injury of flexor muscle, fascia and tendon of right ring finger at wrist and hand level, sequela
  • S66.105 - Unspecified injury of flexor muscle, fascia and tendon of left ring finger at wrist and hand level
  • S66.105A - Unspecified injury of flexor muscle, fascia and tendon of left ring finger at wrist and hand level, initial encounter
  • S66.105D - Unspecified injury of flexor muscle, fascia and tendon of left ring finger at wrist and hand level, subsequent encounter
  • S66.105S - Unspecified injury of flexor muscle, fascia and tendon of left ring finger at wrist and hand level, sequela
  • S66.106 - Unspecified injury of flexor muscle, fascia and tendon of right little finger at wrist and hand level
  • S66.106A - Unspecified injury of flexor muscle, fascia and tendon of right little finger at wrist and hand level, initial encounter
  • S66.106D - Unspecified injury of flexor muscle, fascia and tendon of right little finger at wrist and hand level, subsequent encounter
  • S66.106S - Unspecified injury of flexor muscle, fascia and tendon of right little finger at wrist and hand level, sequela
  • S66.107 - Unspecified injury of flexor muscle, fascia and tendon of left little finger at wrist and hand level
  • S66.107A - Unspecified injury of flexor muscle, fascia and tendon of left little finger at wrist and hand level, initial encounter
  • S66.107D - Unspecified injury of flexor muscle, fascia and tendon of left little finger at wrist and hand level, subsequent encounter
  • S66.107S - Unspecified injury of flexor muscle, fascia and tendon of left little finger at wrist and hand level, sequela
  • S66.108 - Unspecified injury of flexor muscle, fascia and tendon of other finger at wrist and hand level
  • S66.108A - Unspecified injury of flexor muscle, fascia and tendon of other finger at wrist and hand level, initial encounter
  • S66.108D - Unspecified injury of flexor muscle, fascia and tendon of other finger at wrist and hand level, subsequent encounter
  • S66.108S - Unspecified injury of flexor muscle, fascia and tendon of other finger at wrist and hand level, sequela
  • S66.109 - Unspecified injury of flexor muscle, fascia and tendon of unspecified finger at wrist and hand level
  • S66.109A - Unspecified injury of flexor muscle, fascia and tendon of unspecified finger at wrist and hand level, initial encounter
  • S66.109D - Unspecified injury of flexor muscle, fascia and tendon of unspecified finger at wrist and hand level, subsequent encounter
  • S66.109S - Unspecified injury of flexor muscle, fascia and tendon of unspecified finger at wrist and hand level, sequela

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code S66.10 are found in the index:


Code Classification

  • Injury, poisoning and certain other consequences of external causes (S00–T98)
    • Injuries to the wrist, hand and fingers (S60-S69)
      • Injury of muscle, fascia and tendon at wrist and hand level (S66)

Code History

  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016
    (First year ICD-10-CM implemented into the HIPAA code set)
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021

Information for Patients


Hand Injuries and Disorders

No matter how old you are or what you do for a living, you are always using your hands. When there is something wrong with them, you may not be able to do your regular activities.

Hand problems include

  • Carpal tunnel syndrome - compression of a nerve as it goes through the wrist, often making your fingers feel numb
  • Injuries that result in fractures, ruptured ligaments and dislocations
  • Osteoarthritis - wear-and-tear arthritis, which can also cause deformity
  • Tendinitis - irritation of the tendons
  • Disorders and injuries of your fingers and thumb
  • Brachial plexopathy (Medical Encyclopedia)
  • Claw hand (Medical Encyclopedia)
  • Dupuytrens contracture (Medical Encyclopedia)
  • Hand fracture - aftercare (Medical Encyclopedia)
  • Hand or foot spasms (Medical Encyclopedia)
  • Hand x-ray (Medical Encyclopedia)
  • Radial nerve dysfunction (Medical Encyclopedia)
  • Ulnar nerve dysfunction (Medical Encyclopedia)

[Learn More]

Wrist Injuries and Disorders

Your wrist is made up of eight small bones known as carpals. They support a tube that runs through your wrist. That tube, called the carpal tunnel, has tendons and a nerve inside. It is covered by a ligament, which holds it in place.

Wrist pain is common. Repetitive motion can damage your wrist. Everyday activities like typing, racquet sports or sewing can cause pain, or even carpal tunnel syndrome. Wrist pain with bruising and swelling can be a sign of injury. The signs of a possible fracture include misshapen joints and inability to move your wrist. Some wrist fractures are a result of osteoporosis.

Other common causes of pain are

  • Sprains and strains
  • Tendinitis
  • Arthritis
  • Gout and pseudogout
  • Colles wrist fracture - aftercare (Medical Encyclopedia)
  • De Quervain tendinitis (Medical Encyclopedia)
  • Wrist arthroscopy (Medical Encyclopedia)
  • Wrist pain (Medical Encyclopedia)
  • Wrist sprain - aftercare (Medical Encyclopedia)

[Learn More]