My understanding is that physiatry (PM&R) comes in two flavors--inpatient and outpatient.
Outpatient physiatry - Currently, the more popularly practiced PM&R is the outpatient version. Outpatient physiatry concerns itself with musculoskeletal disorders that are not rheumatologic in nature. This means nerve entrapment, osteoarthritis, muscle strain, tendinopathies, axial pain, and sports injuries. Treatment usually involves some form of medical management, minimally invasive procedure or a combination of the two. Whereas a rheumatologist would treat rheumatoid arthritis with some immunosuppressant a physiatrist would treat a patient with osteoarthritis of the knee with an ultrasound guided cortisone injection, PT and or med management.
The physiatrist uses ultrasound to diagnose nerve entrapments, tendinitis (i.e. plantar fasciitis), shoulder cuff tears, and more. Ultrasound can also be used to inject cortisone, platelet rich plasma and other regenerative treatments like bone marrow aspirate concentrate. Regenerative medicine is still an area of research and results are mixed. Physiatrists have been a part of the development of the tenex procedure at Mayo as well, which can be used for microinvasive and surgical debridement of diseased tendons--think refractory plantar fasciitis, tennis elbow, golfers elbow, and more (google 'tenex dr. oz').
Physiatrists are also pioneering technology for carpal tunnel release under ultrasound guidance (google 'sonex carpal tunnel release'). The techniques and possibilities using musculoskeletal ultrasound are rapidly expanding thanks to many physiatrists.
Physiatrists also perform various pain procedures (with and without fellowship depending on residency exposure) for axial pain such as epidural steroid injections, radiofrequency ablation of nerves, medial branch blocks, nerve blocks, kyphoplasty etc. With a pain fellowship, physiatrists can do minor surgical procedures such as spinal cord stimulator and dorsal root ganglion stimulator implantation for chronic pain and other conditions like complex reflex dystrophy syndrome.
Physiatrists also perform botox injections of the muscles for spasticity management in patients with stroke, cerebral palsy or dystonia. All physiatrists learn electromyography (EMG) is residency so they are competent in using EMG and nerve conduction studies to identify radiculopathies and nerve entrapments to assist neurosurgeons and orthopedic surgeons in identifying pathologic nerves that they can go after during operation. EMG can also be used to assist in the diagnose of ALS and other neuromusculoskeletal disorders. Lastly, PM&R docs are knowledgeable in various orthotics, prosthetics and other assistive devices to help patients regain function despite a disability.
Inpatient physiatry - This is currently a less popularly practiced form of PM&R, but those that do practice inpatient PM&R generally enjoy it very much. Following a stroke, for example, patients suffer from many new neurologic sequelae that affect their ability to return to their activities of daily living. A stroke can result in problems communicating, swallowing, walking, sleeping, depression, issues with urinating, and more. Rather than shipping out patients with fresh strokes or spinal cord injuries, a PM&R doctor will admit them to an inpatient floor which can be an attachment to the main hospital or a free-standing facility. The PM&R doctor will manage their medical conditions to ensure they don't develop pneumonia, UTI, CHF, fall, re-stroke etc. during their inpatient stay. The patient will undergo intensive PT, OT, and speech pathology for 3 hours each day. It has been shown that stroke patients that receive inpatient rehabilitation treatment rather than return home or go to a SNF decreases morbidity and mortality as well as reduces government costs in the long run. This type of work can be monotonous for some people because the patients are relatively stable compared to a patient that acutely presents with a new onset stroke, for example. Nonetheless, these patients are still sick and can quickly deteriorate. Patients may stay on the inpatient floor under the supervision of a PM&R doc for days or weeks depending on the severity of their condition. PM&R doctors usually take call for their patients in the inpatient setting from home. Because the acuity of these patients is generally less than that of patients that arrive to the ED acutely, they usually have less emergent issues. In the private sector, many PM&R doctors take second call and have a hospitalist cover acute issues overnight.
Independent medical examinations - Physiatrists often supplement their income doing independent medical examinations due to their extensive knowledge of brain and spinal cord injury, neurorehabilitation, and musculoskeletal disorders. This work is akin to what an occupational physician would do.
Research opportunities - If you are interested in research then PM&R offers many opportunities looking at long term outcomes of stroke patients, spinal cord and brain injury patients etc. There are also research opportunities in regenerative medicine, pain medicine, and sports medicine. Areas of research in this spectrum have gained popularity especially with recent advancements in ultrasound. If you are interested in product development there are also opportunities to work as an engineer or with engineers in developing new assistive devices for patients. There is clinical research in practically anything you can think of related to musculoskeletal disorders and disability.
There is quite a bit of heterogeneity with regards to how a PM&R doc chooses to practice. The way a physiatrist practices can be dependent on the niche they create within their community or academic center. If you work in the private outpatient setting practice you would mostly work as a sports-pain hybrid physician. Inpatient physician you are doing what is described above and leading an interdisciplinary team for patients that have undergone stroke, brain or spinal cord injury. Some physiatrists practice both inpatient and outpatient physiatry.
I agree, but do you have an actual answer.. or not?