Branches of medicine

Working together as an interdisciplinary team, many highly trained health professionals besides medical practitioners are involved in the delivery of modern health care. Some examples include: nurses, laboratory scientists, pharmacists, physiotherapists, speech therapists, occupational therapists, dietitians and bioengineers.

The scope and sciences underpinning human medicine overlap many other fields. Dentistry and psychology, while separate disciplines from medicine, are sometimes also considered medical fields. Physician assistants, nurse practitioners and midwives treat patients and prescribe medication in many legal jurisdictions. Veterinary medicine applies similar techniques to the care of animals.

Medical doctors have many specializations and subspecializations which are listed below. There are variations from country to country regarding which specialities certain subspecialities are in.

Basic sciences

 * Anatomy is the study of the physical structure of organisms. In contrast to macroscopic or gross anatomy, cytology and histology are concerned with microscopic structures.
 * Biochemistry is the study of the chemistry taking place in living organisms, especially the structure and function of their chemical components.
 * Biostatistics is the application of statistics to biological fields in the broadest sense. A knowledge of biostatistics is essential in the planning, evaluation, and interpretation of medical research. It is also fundamental to epidemiology and evidence-based medicine.
 * Cytology is the microscopic study of individual cells.
 * Embryology is the study of the early development of organisms.
 * Epidemiology is the study of the demographics of disease processes, and includes, but is not limited to, the study of epidemics.
 * Genetics is the study of genes, and their role in biological inheritance.
 * Histology is the study of the structures of biological tissues by light microscopy, electron microscopy and immunohistochemistry.
 * Immunology is the study of the immune system, which includes the innate and adaptive immune system in humans, for example.
 * Microbiology is the study of microorganisms, including protozoa, bacteria, fungi, and viruses.
 * Neuroscience includes those disciplines of science that are related to the study of the nervous system. A main focus of neuroscience is the biology and physiology of the human brain and spinal cord.
 * Nutrition is the study of the relationship of food and drink to health and disease, especially in determining an optimal diet. Medical nutrition therapy is done by dietitians and is prescribed for diabetes, cardiovascular diseases, weight and eating disorders, allergies, malnutrition, and neoplastic diseases.
 * Pathology is the study of disease&mdash;the causes, course, progression and resolution thereof.
 * Pharmacology is the study of drugs and their actions.
 * Physiology is the study of the normal functioning of the body and the underlying regulatory mechanisms.
 * Toxicology is the study of hazardous effects of drugs and poisons.

Diagnostic specialties

 * Clinical laboratory sciences are the clinical diagnostic services which apply laboratory techniques to diagnosis and management of patients. In the United States these services are supervised by a pathologist. The personnel that work in these medical laboratory departments are technically trained staff, each of whom usually hold a medical technology degree, who actually perform the tests, assays, and procedures needed for providing the specific services.
 * Transfusion medicine is concerned with the transfusion of blood and blood component, including the maintenance of a "blood bank".
 * Cellular pathology is concerned with diagnosis using samples from patients taken as tissues and cells using histology and cytology.
 * Clinical chemistry is concerned with diagnosis by making biochemical analysis of blood, body fluids and tissues.
 * Hematology is concerned with diagnosis by looking at changes in the cellular composition of the blood and bone marrow as well as the coagulation system in the blood.
 * Clinical microbiology is concerned with the in vitro diagnosis of diseases caused by bacteria, viruses, fungi,  and parasites.
 * Clinical immunology is concerned with disorders of the immune system and related body defenses. It also deals with diagnosis of allergy.
 * Radiology is concerned with imaging of the human body, e.g. by x-rays, x-ray computed tomography, ultrasonography, and nuclear magnetic resonance tomography.
 * Interventional radiology is concerned with using imaging of the human body, usually from CT, ultrasound, or fluoroscopy, to do biopsies, place certain tubes, and perform intravascular procedures.
 * Nuclear Medicine uses radioactive substances for in vivo and in vitro diagnosis using either imaging of the location of radioactive substances placed into a patient, or using in vitro diagnostic tests utilizing radioactive substances.
 * Clinical Neurophysiology is concerned with testing the physiology or function of the central and peripheral aspects of the nervous system. These kinds of tests can be divided into recordings of: (1) spontaneous or continuously running electrical activity, or (2) stimulus evoked responses.
 * Electroencephalography - EEG is concerned with testing the gross function of the brain.
 * Electromyography - EMG is concerned with testing the function of muscles and neuromuscular junctions.
 * Evoked potential - An EP is concerned with testing the nerve pathways involved in both sensory and motor functions.
 * Nerve conduction study
 * Polysomnography / Sleep Study

Clinical disciplines

 * Anesthesiology (AE) or anaesthesia (BE) is the clinical discipline concerned with providing anesthesia. Pain medicine is often practiced by specialised anesthesiologists.
 * Dermatology is concerned with the skin and its diseases. In the UK, dermatology is a subspeciality of general medicine.
 * Emergency medicine is concerned with the diagnosis and treatment of acute or life-threatening conditions, including trauma, surgical, medical, pediatric, and psychiatric emergencies.
 * General practice, family practice, family medicine or primary care is, in many countries, the first port-of-call for patients with non-emergency medical problems. Family doctors are usually able to treat over 90% of all complaints without referring to specialists.
 * Hospital medicine is the general medical care of hospitalized patients. Doctors whose primary professional focus is hospital medicine are called hospitalists.
 * Internal medicine is concerned with systemic diseases of adults, i.e. those diseases that affect the body as a whole (restrictive, current meaning), or with all adult non-operative somatic medicine (traditional, inclusive meaning), thus excluding pediatrics, surgery, gynecology and obstetrics, and psychiatry. There are several subdisciplines of internal medicine:
 * Cardiology is concerned with the cardiovascular system and its diseases.
 * Critical care medicine or intensive care medicine is concerned with the therapy of patients with serious and life-threatening disease or injury. Intensive care medicine employs invasive diagnostic techniques and (temporary) replacement of organ functions by technical means. This field is often associated with Pulmonology.
 * Endocrinology is concerned with the endocrine system (i.e. endocrine glands and hormones) and its diseases, including diabetes and thyroid diseases.
 * Gastroenterology is concerned with the alimentary tract.
 * Geriatrics is concerned with medical care of the elderly.
 * Hematology (AE) or haematology (BE) is concerned with the blood and its diseases. Hematology is part of oncology in the US, though the disciplines are separate in the UK.
 * Hepatology is concerned with the liver and biliary tract, and is usually a part of gastroenterology.
 * Infectious diseases is concerned with the study, diagnosis and treatment of diseases caused by biological agents.
 * Nephrology is concerned with diseases of the kidneys.
 * Oncology is devoted to the study, diagnosis, and treatment of cancer and other malignant diseases, and is often grouped with hematology.
 * Proctology specializes in treatment of disease in the rectum, anus, and colon.
 * Pulmonology, chest medicine, respiratory medicine, or lung medicine is concerned with diseases of the lungs and the respiratory system.
 * Rheumatology is devoted to the diagnosis and treatment of inflammatory diseases of the joints and other organ systems, such as arthritis.
 * Naturopathic medicine is concerned with primary care, natural remedies, patient education and disease prevention.
 * Neurology is concerned with the diagnosis and treatment of nervous system diseases. It is a subspeciality of general medicine in the UK.
 * Obstetrics and gynecology (often abbreviated as Ob/Gyn) are concerned respectively with childbirth and the female reproductive and associated organs. Reproductive medicine and fertility medicine are generally practiced by gynecological specialists.
 * Palliative care is a relatively modern branch of clinical medicine that deals with pain and symptom relief and emotional support in patients with terminal diseases including cancer and heart failure.
 * Pediatrics (AE) or paediatrics (BE) is devoted to the care of infants, children, and adolescents. Like internal medicine, there are many pediatric subspecialities for specific age ranges, organ systems, disease classes, and sites of care delivery. Most subspecialities of adult medicine have a pediatric equivalent such as pediatric cardiology, pediatric endocrinology, pediatric gastroenterology, pediatric hematology, pediatric oncology, pediatric ophthalmology, and neonatology.
 * Physical medicine and rehabilitation (or physiatry) is concerned with functional improvement after injury, illness, or congenital disorders.
 * Preventive medicine is the branch of medicine concerned with preventing disease.
 * Community health or public health is an aspect of health services concerned with threats to the overall health of a community based on population health analysis.
 * Occupational medicine's principal role is the provision of health advice to organizations and individuals to ensure that the highest standards of health and safety at work can be achieved and maintained.
 * Psychiatry is a branch of medicine that studies and treats mental disorders. Related non-medical fields are psychotherapy and clinical psychology. There are several subdisciplines of psychiatry:
 * Child and adolescent psychiatry focuses on the care of children and adolescents with mental, emotional, and learning problems including ADHD, autism, and family conflicts.
 * Geriatric psychiatry focuses on the care of elderly people with mental illnesses including dementias, post-stroke cognitive changes, and depression.
 * Addiction psychiatry focuses on substance abuse and its treatment.
 * Forensic psychiatry focuses on the interface of psychiatry and law.
 * Radiation therapy is concerned with the therapeutic use of ionizing radiation and high energy elementary particle beams in patient treatment.
 * Surgical specialties employ operative treatment. Some disciplines are highly specialized and are often not considered subdisciplines of surgery, although their naming might suggest so.
 * General surgery is traditionally defined as the specialty of surgery of the skin, endocrine glands, and abdomen (and, sometimes, the mammary glands). In some countries, it is still deemed a prerequisite training prior to progression to training in certain subspecialties, but lately has evolved into its own subspecialty.
 * Cardiovascular surgery is the surgical specialty that is concerned with the heart and major blood vessels of the chest.
 * Neurosurgery is concerned with the operative treatment of diseases of the nervous system.
 * Maxillofacial surgery is concerned with the operative treatment of diseases, deformities, and other conditions of lower and middle one-third of face, including oral cavity and teeth (technically a subspeciality of dentistry).
 * Ophthalmology deals with the diseases of the eyes and their treatment.
 * Orthopedic surgery consists of surgery of the locomotor system.
 * Otolaryngology (or otorhinolaryngology or ENT/ear-nose-throat) is concerned with treatment of ear, nose, and throat disorders. The term head and neck surgery defines a closely related specialty which is concerned mainly with the surgical management of cancer of the same anatomical structures.
 * Pediatric surgery treats a wide variety of thoracic and abdominal (and sometimes urologic) diseases of childhood.
 * Plastic surgery includes aesthetic surgery (operations that are done for other than medical purposes) as well as reconstructive surgery (operations to restore function and/or appearance after traumatic or operative mutilation).
 * Surgical oncology is concerned with curative and palliative surgical approaches to cancer treatment.
 * Urology focuses on the urinary tracts of males and females, and on the male reproductive system. It is often practiced together with andrology ("men's health").
 * Vascular surgery is surgery of peripheral blood vessels, i.e. those outside of the chest (usually operated on by cardiovascular surgeons) and of the central nervous system (treated by neurosurgery).
 * Urgent care focuses on delivery of unscheduled, walk-in care outside of the hospital emergency department for injuries and illnesses that are not severe enough to require care in an emergency department.
 * Gender-based medicine studies the biological and physiological differences between the human sexes and how that affects differences in disease.

Interdisciplinary fields
Interdisciplinary sub-specialties of medicine are:
 * Aerospace medicine deals with medical problems related to flying and space travel.
 * Bioethics is a field of study which concerns the relationship between biology, science, medicine and ethics, philosophy and theology.
 * Clinical pharmacology is concerned with how systems of therapeutics interact with patients.
 * Conservation medicine studies the relationship between human and animal health, and environmental conditions. Also known as ecological medicine, environmental medicine, or medical geology.
 * Diving medicine (or hyperbaric medicine) is the prevention and treatment of diving-related problems.
 * Evolutionary medicine is a perspective on medicine derived through applying evolutionary theory.
 * Forensic medicine deals with medical questions in legal context, such as determination of the time and cause of death.
 * Medical humanities includes the humanities (literature, philosophy, ethics, history and religion), social science (anthropology, cultural studies, psychology, sociology), and the arts (literature, theater, film, and visual arts) and their application to medical education and practice.
 * Medical anthropology is a sub-branch of cultural anthropology that is concerned with the application of anthropological and social science theories and methods to questions about health, illness and healing.
 * Medical informatics and medical computer science are relatively recent fields that deal with the application of computers and information technology to medicine.
 * Nosology is the classification of diseases for various purposes.
 * Sports medicine deals with the treatment and preventive care of athletics, amateur and professional. The team includes specialty physicians and surgeons, athletic trainers, physical therapists, coaches, other personnel, and, of course, the athlete.
 * Therapeutics is the field, more commonly referenced in earlier periods of history, of the various remedies that can be used to treat disease and promote health.
 * Travel medicine or emporiatrics deals with health problems of international travelers or travelers across highly different environments.