---
title: "DC 5313 - Group XIII. Function: Extension of hip and flexion of knee; outward and inward rotation of flexed knee; acting with rectus femoris and sartorius (see XIV, 1, 2) synchronizing simultaneous flexion of hip and knee and extension of hip and knee by belt-over-pulley action at knee joint. Posterior thigh group, Hamstring complex of 2-joint muscles: (1) Biceps femoris; (2) semimembranosus; (3) semitendinosus"
diagnostic_code: "5313"
body_system: "Muscle Injuries"
cfr_section: "§ 4.73"
canonical: "https://veteranai.co/va-rating-schedule/muscle-injuries/5313-group-xiii-function-extension-of-hip-and-flexion-of-knee"
source: "https://www.ecfr.gov/current/title-38/section-4.73"
updated: "2026-07-21T17:58:01.618977Z"
---

# DC 5313 - Group XIII. Function: Extension of hip and flexion of knee; outward and inward rotation of flexed knee; acting with rectus femoris and sartorius (see XIV, 1, 2) synchronizing simultaneous flexion of hip and knee and extension of hip and knee by belt-over-pulley action at knee joint. Posterior thigh group, Hamstring complex of 2-joint muscles: (1) Biceps femoris; (2) semimembranosus; (3) semitendinosus

Rated under § 4.73. Body system: Muscle Injuries.

## Rating criteria

| Rating | Criteria |
| --- | --- |
| 40% | Severe |
| 30% | Moderately Severe |
| 10% | Moderate |
| 0% | Slight |

# VA Disability Rating: Muscle Group XIII (Diagnostic Code 5313)

## Understanding Muscle Group XIII Injuries

Muscle Group XIII refers to the **posterior thigh group**, also known as the **hamstring complex**. This group is made up of three muscles that work across two joints:

1. **Biceps femoris**
2. **Semimembranosus**
3. **Semitendinosus**

**What these muscles do:** Muscle Group XIII is responsible for extension of the hip and flexion of the knee, as well as the outward and inward rotation of the flexed knee. Working together with the rectus femoris and sartorius (see Group XIV), these muscles help synchronize the simultaneous flexion of the hip and knee, and the extension of the hip and knee, through a "belt-over-pulley" action at the knee joint.

An injury to this muscle group can affect everyday movements that depend on the coordination between your hip and knee.

## Available Rating Levels

Under **§ 4.73**, injuries to Muscle Group XIII are evaluated within the **Muscle Injuries** body system. The VA assigns a disability rating based on the severity of the muscle injury, using the following levels:

| Rating | Severity |
|--------|-------------------|
| **40%** | Severe |
| **30%** | Moderately Severe |
| **10%** | Moderate |
| **0%** | Slight |

## What the VA Looks For

When rating a Muscle Group XIII injury, the VA evaluates the **degree of severity** of the injury and places it into one of four categories, ranging from **Slight (0%)** up to **Severe (40%)**.

The rating reflects how significantly the injury to the posterior thigh (hamstring) muscles affects the functions this muscle group performs — including hip extension, knee flexion, rotation of the flexed knee, and the coordinated movement of the hip and knee together.

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*This information is provided for general educational purposes and is grounded in the VA rating schedule under Diagnostic Code 5313, § 4.73. Individual rating decisions depend on the specific facts and medical evidence in each case.*

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