---
title: "DC 5321 - Group XXI. Function: Respiration. Muscles of respiration: Thoracic muscle group"
diagnostic_code: "5321"
body_system: "Muscle Injuries"
cfr_section: "§ 4.73"
canonical: "https://veteranai.co/va-rating-schedule/muscle-injuries/5321-group-xxi-function-respiration-muscles-of-respiration"
source: "https://www.ecfr.gov/current/title-38/section-4.73"
updated: "2026-07-21T17:58:02.491968Z"
---

# DC 5321 - Group XXI. Function: Respiration. Muscles of respiration: Thoracic muscle group

Rated under § 4.73. Body system: Muscle Injuries.

## Rating criteria

| Rating | Criteria |
| --- | --- |
| 20% | Severe or Moderately Severe |
| 10% | Moderate |
| 0% | Slight |

# Thoracic Muscle Group Injuries (VA Diagnostic Code 5321)

## Understanding Respiratory Muscle Injuries and Their VA Ratings

The VA evaluates injuries to the **Muscles of respiration: Thoracic muscle group (Group XXI)** under **Diagnostic Code 5321**, found in **§ 4.73** of the VA rating schedule. This diagnostic code falls within the **Muscle Injuries** body system.

### What This Condition Involves

The thoracic muscle group (Group XXI) supports the **function of respiration** — the muscles involved in breathing. An injury to this muscle group can affect how these muscles perform their role in the respiratory process.

### Available Rating Levels

Under Diagnostic Code 5321, the VA assigns disability ratings based on the severity of the muscle injury. The available rating levels are:

| Rating | Severity of Injury |
|--------|--------------------|
| **20%** | Severe or Moderately Severe |
| **10%** | Moderate |
| **0%** | Slight |

### What the VA Looks For

When rating an injury to the thoracic muscle group, the VA classifies the severity of the muscle injury into one of these categories — **Slight**, **Moderate**, or **Severe/Moderately Severe** — and assigns the corresponding percentage. The more severe the injury to these respiratory muscles, the higher the disability rating within the range provided by this diagnostic code.

---

*This information is based on VA Diagnostic Code 5321 under § 4.73 and is provided for general educational purposes. Individual ratings depend on the specific facts of each case as evaluated by the VA.*

Source: https://www.ecfr.gov/current/title-38/section-4.73