S42.209B Unspecified fracture of upper end of unspecified humerus, initial encounter for open fracture

ICD-10-CM S42.209B: Unspecified fracture of upper end of unspecified humerus, initial encounter for open fracture

ICD-10-CM code S42.209B designates an unspecified fracture of the upper end of an unspecified humerus during an initial encounter for an open fracture. The terminology record classifies this concept under the semantic type of Injury or Poisoning and notes it as an active code with a parent concept of S42.209. 1 3

Plain-language overview

This diagnosis code represents a break at the upper end of the upper arm bone where the specific details are unspecified, and it applies to the initial medical encounter for an open fracture. 1

Clinical literature defines fractures of the proximal humerus as those occurring at the top end of the humerus or upper arm bone, providing general anatomical context for this injury category. 2

What this code represents

The official display label for S42.209B is Unspecified fracture of upper end of unspecified humerus, initial encounter for open fracture, and its semantic type is Injury or Poisoning. 1 3

Within the ICD-10-CM hierarchy, S42.209B is a narrower concept under the parent code S42.209, which is the unspecified fracture of the upper end of an unspecified humerus. 1 4

Coding details

The S42.209B terminology record includes an abbreviation noting this is an unsp fracture of upper end of unsp humerus, init for opn fx, and confirms the record status is active. 1

The S42.209 parent concept listing distinguishes the initial encounter for open fracture code S42.209B from the sequela code S42.209S for the same unspecified upper humerus fracture. 4

Documentation considerations

Clinical text indicates that radiographic confirmation, generally plain radiography, is used to verify proximal humerus fractures before patients are sent home or admitted to the hospital. 2

What the sources add

While terminology sources define the S42.209B code structure, clinical trial literature adds that rare serious complications like an open fracture or major vascular injury necessitate emergency surgery for proximal humerus injuries. 1 2

Coverage and utilization context

Historical mapping data links the ICD-10-CM code S42.209B to the ICD-9-CM diagnosis code 812.10 for an open fracture of an unspecified part of the upper end of the humerus. 5

Sources

1. ICD-10-CM S42.209B terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Bookshelf — ncbi.nlm.nih.gov; accessed 2026-07-27.
3. EVS Explore — evsexplore.semantics.cancer.gov; accessed 2026-07-27.
4. EVS Explore — evsexplore.semantics.cancer.gov; accessed 2026-07-27.
5. ICD-9-CM Diagnosis Code 812.10 : Open fracture of unspecified part of upper end of humerus — icd9data.com; accessed 2026-07-27.