S50.842D External constriction of left forearm, subsequent encounter

ICD-10-CM S50.842D: External constriction of left forearm, subsequent encounter

ICD-10-CM code S50.842D identifies an external constriction of the left forearm during a subsequent encounter. This active diagnosis concept is classified under injuries or poisonings and is nested under a parent code for left forearm constriction. The supplied sources establish its official terminology and code tree placement. 1 3

Plain-language overview

Code S50.842D serves as an active terminology record for an injury or poisoning diagnosis specifically denoting external constriction of the left forearm during a subsequent encounter. 1

What this code represents

The diagnosis S50.842D represents a subsequent encounter for external constriction of the left forearm, distinguishing it from the initial encounter code S50.842A listed within the same code tree. 3

S50.842D is a child concept of the parent code S50.842, which broadly defines external constriction of the left forearm without specifying the encounter type. 1

Coding details

The code tree situates S50.842D among specific left forearm superficial injuries, separating it from external constriction codes affecting the right forearm, unspecified forearm, or the elbow. 3

Documentation considerations

Accurate clinical documentation for this diagnosis aligns with the specific S50.842D terminology, which explicitly denotes the left forearm location and the subsequent encounter status. 1 3

Clinical context

Forearm conditions involving constriction or swelling can relate to excessive exercise, such as rock climbing, which produces a pumped sensation, weakness, and pain in the forearm muscles. 2

What the sources add

While the terminology record defines S50.842D as an injury or poisoning, the clinical case report provides operational context on how repetitive forearm muscle stress induces painful swelling and weakness. 1 2

Comparing the sources reveals that the official terminology record establishes the exact code definition, whereas the code tree source demonstrates its lateral and encounter-based distinctions among related superficial injuries. 1 3

Coverage and utilization context

The supplied sources establish the official code hierarchy and clinical context for forearm injuries, but they do not contain any payer-specific rules or coverage guidelines for S50.842D. 1 2 3

Sources

1. ICD-10-CM S50.842D terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Isolated Chronic Exertional Compartment Syndrome of the Flexor Carpi Radialis: A Case Report — pmc.ncbi.nlm.nih.gov; accessed 2026-07-27.
3. ICD-10-CM 2024 | S50 - Superficial injury of elbow and forearm — unboundmedicine.com; accessed 2026-07-27.