From November 1990 to April 1991, the 48th Infantry Brigade (Mechanized), an Army National Guard unit, was activated under Operation Desert Shield and deployed to the National Training Center, Fort Irwin, California, for training in desert warfare. All casualties requiring care beyond the battalion aid stations were evacuated to the medical company organic to the 48th Brigade, Each of 727 orthopedic patient visits were grouped into one of eight etiologies: trauma, degenerative, overuse, infectious, neoplastic, congenital/pediatric, miscellaneous, and psychiatric. Each case was also classified according to anatomic region, severity, and disposition as well as need for a minor procedure, operation, or referral, Orthopedic casualties in a reserve mechanized infantry brigade undergoing intensive field training primarily arose from four common etiologic/regional presentations: wrist/hand trauma, knee/leg trauma, spine/pelvis degenerative, and ankle/foot overuse, Many of these injuries are predictable consequences of a particular soldier's military occupational specialty and unit mission.