Injury to muscles that lift and move the arm away from the body.
Because the rating levels — slight, moderate, moderately severe, and severe — are defined in 38 CFR § 4.56, evidence that maps directly to those criteria matters most. Medical records documenting the nature and extent of the muscle injury, such as operative reports, imaging, and physical examination findings, can show where your injury falls on that scale.
Examination findings that reflect how well you can raise your arm to shoulder level or swing it forward and backward are directly tied to what these muscles do. Range-of-motion measurements, strength testing of the deltoid and pectoralis major, and notes on muscle wasting, tenderness, or scarring support the severity level your examiner assigns.
Statements from you or people who know you about how the injury affects daily tasks — reaching overhead, lifting, carrying, or work duties that require arm movement — give context to the clinical findings. If your dominant arm is involved, make that clear, since the regulation assigns higher ratings to the dominant side at the severe and moderately severe levels.
Conditions that are often caused or made worse by this one. If you have any of these, they may be claimable as secondary service connection.
