Muscle Group XVIII — Trunk (Lateral Spine)

DC 5318Musculoskeletal38 CFR 4.73, DC 5318

Muscle Group XVIII includes the lateral trunk muscles: the external oblique, internal oblique, transversus abdominis (lateral portion), and quadratus lumborum. These muscles control lateral flexion of the trunk (side bending), rotation of the trunk, and stabilization of the spine during movement and load bearing. In military service, injuries commonly occur from carrying heavy loads asymmetrically (ammo cans, crew-served weapons), twisting movements during combat and vehicle operations, blast injuries to the torso, penetrating wounds from shrapnel to the flank region, and chronic strain from wearing heavy body armor and equipment belts. The VA rates Muscle Group XVIII injuries under 38 CFR 4.73.

How the VA rates this condition

The VA rates this condition based on how much it affects your ability to work and carry out daily activities. The examiner will focus on the functional limitations your condition causes, not just the diagnosis itself.

Diagnostic code

DC 5318

Rating range

0% – 40%

Rating levels

Rating criteria are defined in 38 CFR 4.73, DC 5318. This guide presents a plain-language summary and is not a substitute for the full regulatory text. Always consult a VSO or VA-accredited attorney for case-specific advice.

Rating Levels

Your Muscle Group XVIII injury is severe. There is extensive scarring with severe loss of lateral trunk muscle substance and visible atrophy. Trunk rotation and lateral stability are profoundly impaired, affecting posture, balance, and nearly all physical activities that require torso control.

What the VA looks for

Ragged, depressed, or adherent scars
Severe lateral trunk muscle substance loss with visible atrophy
Muscle swelling and hardening abnormally in contraction
X-ray evidence of retained foreign bodies or bony changes
Profound impairment of trunk rotation and lateral stability
Postural deviation from asymmetric muscle loss

Common Pitfalls

⚠Not documenting your MOS and specific duties that caused the injury — lateral trunk injuries should be linked to asymmetric load carrying, twisting during combat or vehicle operations, blast exposure, or specific penetrating trauma to the flank.
⚠Failing to describe the cardinal signs of muscle disability per 38 CFR 4.56 — loss of power, weakness, lowered threshold of fatigue, fatigue-pain, impairment of coordination, and uncertainty of movement must each be addressed.
⚠Not documenting core instability — lateral trunk muscle weakness undermines overall core stability, which should be assessed through functional testing and documented as it affects virtually all physical activities.
⚠Not distinguishing between muscle injury and spinal condition — if your trunk pain is caused by muscle damage rather than a spine condition, it should be claimed under the muscle injury codes rather than the spine codes to avoid pyramiding issues.

Related DBQ Forms

DBQ Muscle Injuries

View evidence checklist →See secondary conditions →

Condition Rating Guides

Understand what the VA looks for at each rating level — loading conditions…

Muscle Group XVIII — Trunk (Lateral Spine)

How the VA rates this condition

Diagnostic code

DC 5318

Rating range

0% – 40%

Rating levels

Rating Levels

What the VA looks for

Ragged, depressed, or adherent scars
Severe lateral trunk muscle substance loss with visible atrophy
Muscle swelling and hardening abnormally in contraction
X-ray evidence of retained foreign bodies or bony changes
Profound impairment of trunk rotation and lateral stability
Postural deviation from asymmetric muscle loss

Common Pitfalls

⚠Not documenting your MOS and specific duties that caused the injury — lateral trunk injuries should be linked to asymmetric load carrying, twisting during combat or vehicle operations, blast exposure, or specific penetrating trauma to the flank.

⚠Failing to describe the cardinal signs of muscle disability per 38 CFR 4.56 — loss of power, weakness, lowered threshold of fatigue, fatigue-pain, impairment of coordination, and uncertainty of movement must each be addressed.

⚠Not documenting core instability — lateral trunk muscle weakness undermines overall core stability, which should be assessed through functional testing and documented as it affects virtually all physical activities.

⚠Not distinguishing between muscle injury and spinal condition — if your trunk pain is caused by muscle damage rather than a spine condition, it should be claimed under the muscle injury codes rather than the spine codes to avoid pyramiding issues.