S66.802S Unspecified injury of other specified muscles, fascia and tendons at wrist and hand level, left hand, sequela

ICD-10-CM S66.802S: Unspecified injury of other specified muscles, fascia and tendons at wrist and hand level, left hand, sequela

ICD-10-CM code S66.802S designates a sequela of an unspecified injury to specified muscles, fascia, and tendons at the wrist and hand level of the left hand. Soft tissue includes muscles, ligaments, and tendons that support joints. Injuries to these structures can occur due to falls, overuse, or direct impact. This diagnosis code is distinct from HCPCS Level II codes, which are maintained by CMS. 5 6 2

Plain-language overview

The term soft tissue refers to muscles, ligaments, and tendons that surround and support our joints. Injuries to the soft tissue around the wrist and hand can occur due to a fall, overuse, or direct impact. 6

What this code represents

The ICD-10-CM code S66.802S represents an unspecified injury of other specified muscles, fascia, and tendons at the wrist and hand level of the left hand. The code tree explicitly designates this specific diagnosis with a sequela encounter bracket. 5

Coding details

The code tree for S66.802 includes distinct encounter characters for the left hand, such as S66.802A for the initial encounter, S66.802D for a subsequent encounter, and S66.802S for a sequela. Related codes also specify right hand and unspecified hand injuries. 5

Clinical context

Wrist tendons connect the muscles in the forearm to the bones in the hand, and there are about six tendons in the wrist. Irritation and wrist pain can affect any of these tendons if they are overused or sustain an injury such as a sprain. 4

Documentation considerations

Clinical documentation for a laceration of other specified muscles, fascia, and tendons at the wrist and hand level includes laterality and encounter status. An example from a billing article is the code S66.822A for a right hand initial encounter. 3

Coverage and utilization context

HCPCS Level II codes are additional codes created and maintained by the Centers for Medicare & Medicaid Services. The Value Set Authority Center provides a browse window to view complete details by enabling the search, detail, tree, and code clipboard views. 2

What the sources add

A clinical reference from the Cleveland Clinic defines wrist tendon anatomy and inflammation, while a coding reference from Unbound Medicine lists the ICD-10-CM code tree for S66.802S. The coding reference provides the official diagnosis description and sequela designation. 4 5

A National Health Statistics Reports document lists various upper extremity injury codes, including traumatic rupture of an unspecified ligament of the left wrist. A wound care billing article identifies a specific laceration diagnosis code for the right hand initial encounter. 1 3

Sources

1. National Health Statistics Reports — cdc.gov; accessed 2026-07-26.
2. Browse Code Systems — vsac.nlm.nih.gov; accessed 2026-07-26.
3. Article - Billing and Coding: Wound Care (A55909) — cms.gov; accessed 2026-07-26.
4. Wrist Tendonitis: Symptoms, Causes & Treatment — my.clevelandclinic.org; accessed 2026-07-26.
5. ICD-10-CM 2024 | S66 - Injury of muscle, fascia and tendon at wrist and hand level — unboundmedicine.com; accessed 2026-07-26.
6. Soft Tissue Injury: Wrist and Hand | Hull University Teaching Hospitals NHS Trust — hey.nhs.uk; accessed 2026-07-26.