An internist or Internal Medicine doctor is someone who specializes in diagnosing and treating illnesses, diseases, and health problems. Most internists are also primary care doctors and treat patients on a regular basis. They can diagnose and treat common illnesses or more serious problems. Most people see an internist regularly. Those with chronic illnesses may do so on a monthly or even weekly basis. Internists are the most common types of doctors.

A neurologist is a medical professional who specializes in the study and treatment of disorders that affect the brain and nervous system. The nervous system controls and regulates activity and movement in the body. If the nervous system is not functioning properly, the body cannot function. It is the job of a neurologist to find and correct any problems in the nervous system.

A neurosurgeon is a surgeon who specializes in the brain and neurological system. They diagnose and treat disorders of the central and peripheral nervous system. They work closely with neurologists and other medical professionals to provide the best medical care possible to their patients. Some neurosurgeons also specialize in other areas or in specific health problems, diseases, or disorders.

A rheumatologist is a certified internist who is qualified to diagnose and treat arthritic diseases of the joints, muscles, and bones. Rheumatologists can conduct tests and perform procedures that can help relieve the symptoms of various illnesses and diseases that affect the joints, muscles, and bones.