Throughout the 20th century there was much questioning, from both inside and outside the chiropractic profession, as to whether the subluxation was primarily a lesion of malposition, as Dr. Palmer had originally theorized. Many, if not most, chiropractic clinicians and researchers have now concluded that the subluxation is a lesion primarily characterized by loss of joint mobility. Nonetheless, today, many doctors of chiropractic (DCs) continue to believe, and to educate patients to believe that spinal dysfunction is primarily a result of bones of the spine being "out of place". These same DCs routinely speak of a need to align the vertebra of the spine.

The question of whether a subluxation is primarily a lesion of position or of motion is easily answered and explained to the public or to healthcare professionals as follows: the inherent functional capacity of vertebrae is such that they are able to flex, extend, laterally bend, and rotate in relation to the vertebrae above and below them. Therefore, a vertebra has no single place, nor spatial relationship with its adjacent vertebrae, to which it can be returned through spinal adjustment or any other means. It has an infinite number of possible positions/spatial relationships between itself and the adjacent segment.

Additionally, the functional state of a vertebral motor unit (two
adjacent vertebrae and their contiguous and functionally associated
tissues) includes free movement between the two segments. In a state of free, adaptive movement, each vertebra would have the ability to find a dynamic balance and functional relationship to its neighbor. This balance has historically been inappropriately referred to, and confused with "alignment".