Part V, Subpart iii, Chapter 1, Section E Muscle Injuries — M-21-1

Revised July 21, 2022

V.iii.1.E.1.aTypes of Muscle Injuries

A missile that penetrates the body results in two problems

it destroys muscle tissue in its direct path by crushing it, then
the temporary cavitation forces stretch the tissues adjacent to the missile track and result in additional injury or destruction.

Muscles are much more severely disrupted if multiple penetrating projectiles strike in close proximity to each other. Examples of this type of injury are

explosive device injuries
deforming or fragmenting rifle projectiles, or
any rifle projectile that strikes bone.

For additional information regarding types of injuries, the effects of explosions and projectiles, and symptoms and complications, refer to the table below.

Type of Injury	Initial Effects	Signs, Symptoms, and Complications
Gunshots	Entrance and exit wounds result. The amount of damage and relative size of entrance and exit wounds depends on many factors such as caliber of bullet distance from victim organs, bone, blood vessels, and other structures hit. Exit wounds are generally larger than entrance wounds, and bullets are essentially sterile when they reach the body but carry particles into wound which could be sources of infection.
Fragments from explosive devices	Most result in decreased tissue penetration compared to denser rifle bullets.	Multiple fragments in a localized area result in tissue disruption affecting a wide area.
Tears and lacerations	Muscles that become isolated from nerve supply by lacerations will be non-functional.	Torn muscle fibers heal with very dense scar tissue, but the nerve stimulation will not cross this barrier. Parts of muscle isolated from the nerve will most likely remain non-contractile resulting in a strength deficit proportional to amount of muscle tissue disrupted. Treatment for small tears is symptomatic. Large tears/lacerations may require reconstruction.
Through and through wound	Injuring instrument enters and exits one or multiple muscle groups.	Two wounds result entrance wound, and exit wound.

Reference : For more information on the potential for multiple through and through wounds from a single injuring instrument, see Jones v. Principi, 18 Vet.App. 248 (2004).
References: For more information on

muscle groups (MGs) and corresponding diagnostic codes (DCs), see 38 CFR 4.73
anatomical regions of the body, see 38 CFR 4.55(b), and
gunshot wounds (GSWs) with pleural cavity involvement, see 38 CFR 4.97, DC 6840-6845, Note (3).

V.iii.1.E.1.bStandard Muscle Strength Grading System for Examinations

Refer to the table below for information about how muscle strength is evaluated on an examination.

Numeric Grade	Corresponding Strength Assessment	Indications on Exam
(0)	absent	no contraction felt
(1)	trace	muscle can be felt to tighten but no movement is produced
(2)	poor	muscle movement is produced against gravity but cannot overcome resistance
(3)	fair	muscle movement is produced against gravity but cannot overcome resistance
(4)	good	muscle movement is produced against resistance, however, less than normal resistance
(5)	normal	muscle movement can overcome a normal resistance

V.iii.1.E.1.cIdentification of MG in Examination Reports

The examination report must include information to adequately identify the MG affected by either

specifically noting which MG is affected, or
noting which muscles are involved so that the name of the muscles may be used to identify the MG affected.

V.iii.1.E.1.dFractures Associated With GSW/SFW

All fractures associated with a GSW and/or shell fragment wound (SFW) will be considered open because all of them involve an opening to the outside. Most GSW/SFW fractures are also comminuted due to the shattering nature of the injury.

2Applying 38 CFR 4.55, 4.56, and 4.73 for Muscle Injury Evaluations

This topic contains information on applying 38 CFR 4.55, 4.56, and 4.73 for evaluations of muscle injuries, including

general criteria for muscle evaluations
determining whether 38 CFR 4.55 applies to muscle injuries
applying 38 CFR 4.55 to muscle injuries
evaluating
- joint manifestations and muscle damage acting on the same joint, and
- damage to multiple muscles within the same MG
considering peripheral nerve involvement in muscle injuries
evaluating
- muscle injuries with peripheral nerve conditions of different etiology
- scars associated with muscle injuries, and
- painful motion associated with muscle injuries
applying the amputation rule to muscle injuries, and
evaluating muscle disabilities not involving shrapnel, GSWs, or other projectile-type injury.

Revised May 16, 2022

V.iii.1.E.2.aGeneral Criteria for Muscle Evaluations

Evaluation of muscle disabilities is the result of a multi-factorial consideration. However, there are hallmark traits that are suggestive of certain corresponding evaluations. Refer to the following table for additional information regarding these hallmark traits and the suggested corresponding disability evaluation.

If the evidence shows a history of ...	Then consider evaluating the muscle injury as ...
open comminuted fracture with muscle damage, or tendon damage	severe.Note: This level of impairment is specified by regulation at 38 CFR 4.56(a).
through and through or deep penetrating wound by small high velocity missile or large low velocity missile with debridement prolonged infection, or sloughing of soft parts, and intermuscular scarring	at least moderately severe.
through and through injury with muscle damage	no less than moderate.Note: This level of impairment is specified by regulation at 38 CFR 4.56(b).
retained fragments in muscle tissue	at least moderate.
deep penetrating wound without explosive effect of high velocity missile residuals of debridement, or prolonged infection	at least moderate.

Important: No single factor is controlling for the assignment of a disability evaluation for a muscle injury. The entire evidence picture must be taken into consideration.

Reference: For more information on assigning disability evaluations for muscle injuries, see

Tropf v. Nicholson, 20 Vet.App. 317 (2006)
Robertson v. Brown, 5 Vet.App. 70 (1993)
Jones v. Principi, 18 Vet.App. 248 (2004), and
38 CFR 4.55.

V.iii.1.E.2.bDetermining Whether 38 CFR 4.55 Applies to Muscle Injuries

38 CFR 4.55 applies to certain combinations of muscle injuries and joint conditions. Consider the provisions of 38 CFR 4.55 if

there are multiple MGs involved
the MG acts on a joint or joints, and/or
there is peripheral nerve damage to the same body part affected by the muscle.

V.iii.1.E.2.cApplying 38 CFR 4.55 to Muscle Injuries

If more than one MG is injured or affected or if the injured MG acts on a joint, conduct a preliminary review of the evidence to gather information needed to properly apply the provisions of 38 CFR 4.55. The information needed will include whether the

affected MGs are in the same or different anatomic regions
MGs are acting on a single joint or multiple joints, and
joint or joints is/are ankylosed.

After the preliminary review is complete, use the evidence gathered and apply the following table to determine how 38 CFR 4.55 affects the evaluation of the muscle injury.

Step	Action
1	Does the MG(s) act on an ankylosed joint? If yes , go to Step 2. If no , go to Step 4.
2	For MG(s) that act on an ankylosed joint, is the joint an ankylosed knee and is MG XIII disabled? If yes , grant separate evaluations for the ankylosed knee and the MG XIII injury. For the MG XIII injury, assign the next lower level than that which would otherwise be assigned. Then go to Step 3. If no , then is the ankylosed joint the shoulder and are MGs I and II severely disabled? If yes , then assign a single evaluation for the muscle injury and the shoulder ankylosis under DC 5200. The evaluation will be at the level of unfavorable ankylosis. If no , then no evaluation will be assigned for the muscle injury. The combined disability arising from the ankylosis and the muscle injury will be evaluated as ankylosis.
3	For the injury to MG XIII with an associated ankylosed knee, are there other MG injuries in the same anatomical region affecting the pelvic girdle and/or thigh? If no , then no additional change to the evaluation for the muscle injury is warranted. If yes , do the affected MG injuries act on the ankylosed knee? If yes , then no separate evaluation for the muscle injury to a MG other than MG XIII can be assigned, as indicated in Step 2. If no , then for the MG XIII injury that acts on the knee and the injury to another MG of the pelvic girdle and thigh acting on a different joint, is the different joint ankylosed? If yes , then no separate evaluation can be assigned for the other MG injury of the pelvic girdle and thigh, as indicated in Step 2. No further action is warranted. If no , then assign a single evaluation for the MG XIII injury and the injury to the other MG of the pelvic girdle and thigh anatomical region by determining the most severely injured MG and increasing by one level.
4	For muscle injury(ies) acting on unankylosed joint(s), is a single MG injury involved? If yes , then grant a single evaluation for the muscle injury. If no , then are the MG injuries in the same anatomical region? If yes , go to Step 5. If no , go to Step 6.
5	Do the MGs in the same anatomical region act on a single joint? If yes , are the MGs involved MG I and II acting on a shoulder joint? If yes , then assign separate disability evaluations for the MGs, but the combined evaluation cannot exceed the evaluation for unfavorable ankylosis of the shoulder. If no , then for the muscles in the same anatomical region acting on a single joint, assign separate disability evaluations for the MGs, but the combined evaluation must be less than the evaluation that would be normally assigned for unfavorable anklyosis of the joint involved. If no , for the MGs in the same anatomical region acting on different joints, are the MG injuries compensable? If yes , then assign a single disability evaluation for the affected MGs by determining the evaluation for the most severely injured MG, and increasing by one level and using as the combined evaluation. If no , then assign a noncompensable evaluation for the combined MG injuries.
6	For MG injuries in different anatomical areas, is a single unankylosed joint affected? If yes , are MG I and II affected and acting upon the shoulder? If yes , then assign separate disability evaluations for the muscle injuries, but the combined evaluation cannot exceed the evaluation for unfavorable ankylosis of the shoulder. If no , for the MG injuries in different anatomical areas affecting a single unankylosed joint (not including MG I and II acting on the shoulder) assign separate disability evaluations for the muscle injuries, but the combined evaluation must be lower than the evaluation that would be assigned for unfavorable ankylosis of the affected joint. If no , then for MG injuries in different anatomical areas acting on different unankylosed joints, assign separate disability evaluations for each MG injury.

References: For additional information on evaluating

joint manifestations and muscle damage acting on the same joint, see M21-1, Part V, Subpart iii, 1.E.2.d, and
peripheral nerve involvement in muscle injuries, see M21-1 Part V, Subpart iii, 1.E.2.f.

V.iii.1.E.2.dEvaluating Joint Manifestations and Muscle Damage Acting on the Same Joint

A separate evaluation for joint manifestations and muscle damage acting on the same joint are prohibited if both conditions result in the same symptoms.Although LOM is not directly discussed in 38 CFR 4.56, the DC provisions within 38 CFR 4.73 describing the functions of various MGs are describing motion.

The muscles move the joint.
If the joint manifestation is LOM, that manifestation is already compensated through the evaluation assigned by a muscle rating decision.
Evaluating the same symptoms under multiple DCs is prohibited by 38 CFR 4.14.

Note: Consider the degree of disability under the corresponding muscle DC and joint DC and assign the higher evaluation.Exception: Per 38 CFR 4.55(c)(1), if MG XIII is disabled and acts on an ankylosed knee, separate disability evaluations can be assigned for the muscle injury and the knee ankylosis. However, the evaluation for the MG injury will be rated at the next lower level than that which would have otherwise been assigned. Reference: For more information on applying 38 CFR 4.55 when evaluating muscle injuries and joint conditions, see M21-1, Part V, Subpart iii, 1.E.2.b and c.

V.iii.1.E.2.eEvaluating Damage to Multiple Muscles Within the Same MG

A separate evaluation cannot be assigned for each muscle within a single MG. Muscle damage to any of the muscles within the group must be included in a single evaluation assigned for the MG.

V.iii.1.E.2.fConsidering Peripheral Nerve Involvement in Muscle Injuries

When there is nerve damage associated with the muscle injury, use the table below to determine appropriate actions to take to evaluate the nerve damage and the muscle injury.

If ...	Then ...
the nerve damage is in the same body part as the muscle injury, and the muscle injury and the nerve damage affect the same functions of the affected body part	assign a single evaluation for the combined impairment by determining whether the nerve code or the muscle code will result in a higher evaluation. Assign the higher evaluation.Note: If the muscle and nerve evaluations are equal, evaluate with the DC with the highest maximum evaluation available.
the nerve damage is in the same body part as the muscle injury, and the muscle injury and the nerve damage affect entirely different functions of the affected body part	assign separate evaluations for the nerve damage and the muscle injury.

V.iii.1.E.2.gEvaluating Muscle Injuries with Peripheral Nerve Conditions of Different Etiology

The provisions of 38 CFR 4.55 preclude the combining of a muscle injury rating with a peripheral nerve paralysis evaluation involving the same body part when the same functions are affected. A muscle injury and a peripheral nerve paralysis of the same body part, originating from separate etiologies, may not be rated separately.

The exception to this rule is only when entirely different functions are affected.
Etiology of the disability is irrelevant in rendering a determination regarding combining evaluations for muscle injuries and peripheral nerve paralysis.

Example: A Veteran is service-connected (SC) for GSW to the right leg MG XI at 10-percent. SC diabetic peripheral neuropathy develops many years later. The peripheral neuropathy affects the external popliteal nerve. Since MG XI and the external popliteal nerve both control the same functions, dorsiflexion of the foot and extension of the toes, only a single disability evaluation can be assigned under either 38 CFR 4.73, DC 5311 or 38 CFR 4.73, DC 8521, whichever is more advantageous.

V.iii.1.E.2.hEvaluating Scars Associated With Muscle Injuries

Use the table below to determine appropriate action to take when evaluating scars associated with muscle injuries.

If ...	Then ...
there is scarring associated with the muscle injury	assign a separate evaluation for the scar, even if noncompensable.
there is painful or unstable scarring associated with the muscle injury	assign a separate compensable disability evaluation under 38 CFR 4.118, DC 7804.
there is scarring that results in functional loss under 38 CFR 4.118, DC 7805 that is compensable	do not assign a separate evaluation if the body part affected and the functional impairment resulting from the scar are the same as the part and function affected by the muscle injury.

Reference: For more information on assigning separate evaluations for the muscle injury and associated scarring, see

Esteban v. Brown, 6 Vet. App. 259 (1994)
Jones v. Principi, 18 Vet.App. 248 (2004), and
38 CFR 4.14.

V.iii.1.E.2.iEvaluating Painful Motion Associated With Muscle Injuries

Fatigue-pain is a cardinal sign and symptom of muscle disability, as discussed in 38 CFR 4.56(c). Painful motion associated with a muscle injury is consistent with fatigue-pain. As noted in 38 CFR 4.56(d)(2)(iii), a record of consistent complaint of one or more of the cardinal signs and symptoms of muscle disability is consistent with at least moderate disability of the muscles.

V.iii.1.E.2.jApplying the Amputation Rule to Muscle Injuries

The amputation rule applies to musculoskeletal conditions and any associated peripheral nerve injuries. Therefore, when assigning separate evaluations for the muscle injury, peripheral nerve injury directly related to that muscle injury must be considered in applying the amputation rule. References: For more information on

the amputation rule, see 38 CFR 4.68, and
evaluating peripheral nerve disabilities associated with muscle injuries, see M21-1, Part V, Subpart iii, 1.E.2.f.

V.iii.1.E.2.kEvaluating Muscle Disabilities Not Involving Shrapnel, GSWs, or Other Projectile-Type Injury

Generally, apply 38 CFR 4.73 to muscle injuries such as those arising from shrapnel, GSWs, or other projectiles or similar foreign objects entering the muscle from outside the body since the criteria for the evaluation weigh heavily on the type of wound, treatment, and current manifestations of the wound. Generally, a disability such as that arising from injuries such as muscle strains, tears not resulting from injury by a foreign object entering the muscle, or muscle atrophy due to a SC joint or nerve injury should be evaluated under an appropriate DC based on associated functional impairment.Exception : Compartment syndrome is evaluated under 38 CFR 4.73, DC 5331 using the muscle injury evaluation criteria.

End of Part V, Subpart iii, Chapter 1, Section E

Part V, Subpart iii, Chapter 1, Section EMuscle Injuries