Pathology, part of the basic science of medicine and nursing, is an understanding of how cellular mechanisms and organ systems function cojointly in the physical body. An awareness of the biomechanics and pathophysiology related to a particular mechanism of injury (MOI) provides a more appreciative sense of how tissues become damaged. Cognizance of the variables and risk factors involved in MOI specific to anatomic structures not only helps the Health Care Provider (HCP) decide which treatment options are necessary, but knowing risk factors helps in preventive tactics, counseling an athlete for optimal training, and rehabilitation of the injured athlete. This article discusses the pathophysiology related to anterior cruciate ligament (ACL) injury, one of the most common and costly ligamentous knee injuries. The differentiation between contact versus noncontact mechanisms and risk factors plaguing women athletes will be listed.