hi, thanks for the query, it is an interesting question. physical therapy is a field of medical science which assesses, examines, diagnoses and treats a patient with physical modalities like heat therapy, cold therapy, electrotherapy, exercise therapy, hydrotherapy, manual therapy or mobilizations and various forms of specialized exercises based on scientific and proven concepts. physical medicine - is sometimes and in some parts of the world is used as a synonym to physical therapy. But majorly it is used in context with the rehabilitation of the patients. rehabilitation means bringing back a patient into his/her normal life in which he/she was prior to illness. and most commonly it is required in conditions like head injury, spinal cord injury, stroke, knee replacement and hip replacement surgeries, in all of these the patients faces physical as well as systemic problems to perform his/her daily activities so physical medicine more appropriate called as physical medicine and rehabilitation will help the patient. and In this not only a physical therapist but an occupational therapist, speech therapist, orthotist, prosthetist etc will play an important role. i hope this helps feel free to ask further queries