This FY 2021 Update is the 3rd update to the original Taxonomy of Injuries* report at:1) A Taxonomy of Injuries for Public Health Monitoring and Reporting; with Addendum 1 and Addendum 2 (Body Regions and Injury Types. through Fiscal Year 2018) available at https://apps.dtic.mil/docs/citations/AD10394812) The FY 2019 Update is available at https://apps.dtic.mil/docs/citations/AD10648943) The FY 2020 Update is available at https://apps.dtic.mil/sti/citations/AD1084570* The injury taxonomy defines all injuries monitored by the Army and defines different types of injuries based on causal energy sources (i.e., mechanical/kinetic energy, environmental (heat, cold), poisoning/chemical exposures, etc.). Because Army surveillance uses medical diagnoses in Soldiers electronic health records, the taxonomy injury definition is operationalized with over 12,000 specific medical diagnostic codes (International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM)). Each year the Centers for Disease Control and Prevention (CDC) updates the ICD-10-CM codes. These APHC taxonomy updates are to document any changes to the Army injury codes as well as non-injury codes used to depict the annual distribution of all Active Duty soldiers medical encounters, characterized as the burden of 16 medical diagnoses categories (injury and 15 other categories).