Above insertion of deltoid (DC 5121)
Diagnostic Code 5121 covers amputations or complete loss of use of your arm above where the deltoid muscle attaches (that's the point muscle on your shoulder). This is located roughly in the upper third of your upper arm bone. The VA gives this a fixed rating percentage based on the specific location and extent of the amputation or loss of use - you'll need to check the amputation rating table in 38 CFR § 4.71a to find your exact percentage. This is typically a high-percentage rating since it involves significant loss of arm function.
Disclaimer: This tool is for informational purposes only and is not legal or medical advice. Always consult with your VSO representative or a qualified veterans benefits attorney for guidance on your specific claim.