S21.101D Unspecified open wound of right front wall of thorax without penetration into thoracic cavity, subsequent encounter

ICD-10-CM Diagnosis Code S21.101D

ICD-10-CM code S21.101D is an unspecified open wound of the right front wall of the thorax without penetration into the thoracic cavity, designated for a subsequent encounter. Official sources from CMS and the NLM VSAC establish this exact descriptor. The sources also list related thoracic wall injuries to distinguish initial from subsequent encounters and penetration status. 1 3

Plain-language overview

Code S21.101D identifies an unspecified open wound located on the right front wall of the thorax that does not penetrate into the thoracic cavity, specifically for a subsequent encounter. 3

What this code represents

The official ICD10CM code system descriptor for S21.101D is an unspecified open wound of the right front wall of thorax without penetration into the thoracic cavity, subsequent encounter. 3

Coding details

CMS manuals list S21.101D alongside descriptors for initial encounters of the same right front thoracic wall injury, establishing a distinction between initial and subsequent encounter characters within this code category. 1 2

The CMS v37.0 manual lists S21.101D separately from unspecified open wounds of the right front wall of the thorax with penetration into the thoracic cavity, establishing a distinction based on thoracic cavity penetration. 1

Documentation considerations

The official descriptor for S21.101D specifies the right front wall of the thorax, the absence of thoracic cavity penetration, and a subsequent encounter, providing the exact clinical elements documented for this code. 3

What the sources add

The NLM VSAC provides the code system and exact descriptor for S21.101D, while the CMS manuals list this code among related thoracic wall wound descriptors, adding operational context regarding initial versus subsequent encounters and penetration status. 1 2 3

The CMS v37.0 manual includes S21.101D in a list with puncture wounds and unspecified open wounds of the left, right, and unspecified thorax walls, providing context on how this specific diagnosis relates to other thoracic injuries. 1

Sources

1. ICD-10-CM/PCS MS-DRG v37.0 Definitions Manual — cms.gov; accessed 2026-07-25.
2. ICD-10-CM/PCS MS-DRGv33 Definitions Manual — cms.gov; accessed 2026-07-25.
3. Browse Code Systems — vsac.nlm.nih.gov; accessed 2026-07-25.