Chiropractic is a form of alternative medicine mostly concerned with the diagnosis and treatment of mechanical disorders of the musculoskeletal system, especially the spine.[1][2] Some proponents, especially those in the field’s early history, have claimed that such disorders affect general health via the nervous system,[2] through vertebral subluxation, claims which are not based on scientific evidence. The main chiropractic treatment technique involves manual therapy, especially spinal manipulation therapy (SMT), manipulations of other joints and soft tissues.[3] Its foundation is at odds with mainstream medicine, and chiropractic is sustained by pseudoscientific ideas such as subluxation and “innate intelligence” that reject science.[4][5][6][7][8] Chiropractors are not medical doctors.[9]

Numerous controlled clinical studies of treatments used by chiropractors have been conducted, with conflicting results.[4] Systematic reviews of this research have not found evidence that chiropractic manipulation is effective, with the possible exception of treatment for back pain.[4] A critical evaluation found that collectively, spinal manipulation was ineffective at treating any condition.[10] Spinal manipulation may be cost-effective for sub-acute or chronic low back pain but the results for acute low back pain were insufficient.[11] The efficacy and cost-effectiveness of maintenance chiropractic care are unknown.[12] There is not sufficient data to establish the safety of chiropractic manipulations.[13] It is frequently associated with mild to moderate adverse effects, with serious or fatal complications in rare cases.[14] There is controversy regarding the degree of risk of vertebral artery dissection, which can lead to stroke and death, from cervical manipulation.[15] Several deaths have been associated with this technique[14] and it has been suggested that the relationship is causative,[16][17] a claim which is disputed by many chiropractors.[17]

Chiropractic is well established in the United States, Canada, and Australia.[18] It overlaps with other manual-therapy professions such as osteopathy and physical therapy.[19] Most who seek chiropractic care do so for low back pain.[20] Back and neck pain are considered the specialties of chiropractic, but many chiropractors treat ailments other than musculoskeletal issues.[4] Many chiropractors describe themselves as primary careproviders,[4][21] but the chiropractic clinical training does not support the requirements to be considered primary care providers,[2] so their role on primary care is limited and disputed.[2][21] Chiropractic has two main groups: “straights”, now the minority, emphasize vitalism, “innate intelligence”, and consider vertebral subluxations to be the cause of all disease; “mixers”, the majority, are more open to mainstream views and conventional medical techniques, such as exercise, massage, and ice therapy.[22]

D. D. Palmer founded chiropractic in the 1890s,[23] after saying he received it from “the other world”,[24] and his son B. J. Palmer helped to expand it in the early 20th century.[23] Throughout its history, chiropractic has been controversial.[25][26] Despite the overwhelming evidence that vaccination is an effective public health intervention, among chiropractors there are significant disagreements over the subject,[27] which has led to negative impacts on both public vaccination and mainstream acceptance of chiropractic.[28] The American Medical Association called chiropractic an “unscientific cult” in 1966[29] and boycotted it until losing an antitrust case in 1987.[21] Chiropractic has had a strong political base and sustained demand for services; in recent decades, it has gained more legitimacy and greater acceptance among conventional physicians and health plans in the United States.[21]


The United States of America (USA), commonly referred to as the United States (U.S.), America, and sometimes the States, is a federal republic[17][18] consisting of 50 statesand a federal district. The 48 contiguous states and Washington, D.C., are in central North America between Canada and Mexico. The state of Alaska is located in the northwestern part of North America and the state of Hawaii is an archipelago in the mid-Pacific. The country also has five populated and nine unpopulated territories in the Pacific and the Caribbean. At 3.80 million square miles (9.85 million km2)[4] and with around 318 million people, the United States is the world’s fourth-largest country by total area and third-largest by population. It is one of the world’s most ethnically diverse and multicultural nations, the product of large-scale immigration from many countries.[19]The geography and climate of the United States is also extremely diverse, and it is home to a wide variety of wildlife.[20]

The United States is a developed country and has the world’s largest national economy.[6] The economy is fueled by an abundance of natural resources and high worker productivity.[29] While the U.S. economy is considered post-industrial, it continues to be one of the world’s largest manufacturers.[30] The country accounts for 37% of global military spending,[31] being the world’s foremost economic and military power, a prominent political and cultural force, and a leader in scientific research and technological innovations.[32]