The birth of chiropractic as a profession occurred in the year 1895 when Daniel David Palmer (1845-1913) adjusted the spine of a deaf man, William Harvey Lillard. Daniel David Palmer established the Palmer School in Davenport, Iowa, in 1896.

Wilhelm Conrad Rontgen was a German physicist (1845-1923). In 1895, at age 50, he produced and detected x-rays (Rontgen rays). For that achievement, he was awarded the very first Nobel Prize in Physics in 1901. A few weeks after his discovery, he produced the first “x-ray picture” by applying this new technology to the bones of his wife’s hand. The following month he published the first paper on his new discovery, titled “On a New Kind of Rays.” This is considered to be the birth of diagnostic radiology.

Bartlett Joshua Palmer (1882-1961) was the son of Daniel David Palmer. Bartlett Joshua Palmer took over the Palmer School in 1906. In 1910, Bartlett Joshua (BJ) Palmer began to apply x-rays for taking images of the spine. These were some of the first spinal x-rays ever taken. BJ Palmer called the exposing of x-rays of the spine spinography (1).

Chiropractic and X-rays were born in the same year, 1895, by 50-year-old men who were born in 1845. The new technology of x-rays was quickly embraced by chiropractic, primarily for the purpose of imaging the spine. The relationship between chiropractic and x-rays continues through today.

•••••••••

Today’s chiropractor has extensive undergraduate education in radiology, and post-graduate certification in radiology is available. Most field practitioner chiropractors frequently attend continuing education classes in radiology. Today, chiropractors take x-rays on patients for a variety of reasons:

• Pathology: This includes entities such as fracture, infection, malignancy, and benign tumors. In my clinical practice, I have taken x-rays on patients and diagnosed such entities as rib fractures, dens fracture, Hangman’s fracture, Jefferson’s fracture, uncinate process fracture, spinous/transverse process fracture, vertebral body fracture, cervical spine pillar fracture, spondylolysis with spondylolisthesis; osteogenic sarcoma, multiple myeloma, a few metastatic cancers; osteoid osteoma, giant cell tumor; osteomyelitis; etc.
• Metabolic: This includes diagnosis such as rheumatoid arthritis, ankylosing spondylitis, Otto’s pelvis.
• Developmental: Examples would include slipped capital femoral epiphysis, congenital hip dislocation, Legg-Calves-Perth’s disease, etc.
• Degeneration: This would include disc disease, facet arthrosis, spondylosis, central canal stenosis, lateral recess stenosis, etc.
• Anomalies: This would include block vertebrae, hemi vertebrae, demi vertebrae, Klippel-Feil syndrome, cervical ribs, os odontoideum, lumbosacral transitional segments (sacralization, lumbarization), facet tropism, dysplasia, agenesis, spina bifida, etc.
• Biomechanics: This would include segmental malpositions, postural distortions, leg length inequality, scoliosis, ligamentous instabilities (stress radiography), etc. Many chiropractors base their adjustive line-of-drive on spinal biomechanical measurements.

•••••••••

In 1983, Stephen Kovach and Eldon Huslig published a study in the Journal of Manipulative and Physiological Therapeutics, titled (2):

Prevalence of diagnoses on the basis of radiographic evaluation of chiropractic cases

In this study they show the results of a review of all the radiographic examinations performed at the National College of Chiropractic Clinic during the 1982 calendar year. They show how these radiographs helped in the diagnosis of musculoskeletal, cardiopulmonary, or abdominal syndromes. They state:

“The use of plain film radiography has long been a staple of the chiropractic profession. Radiographic examinations are a valuable tool in the chiropractic diagnosis of a patient’s condition.”

•••••••••

The following year, 1984, Kovach and Huslig published another study in the Journal of Manipulative and Physiological Therapeutics, titled (3):

Shoulder pain and Pancoast tumor: A diagnostic dilemma

In this study, the authors describe a case of shoulder pain radiating into the arm and ulnar side of the hand. Cervical spine radiographs were exposed. A careful evaluation showed a Pancoast tumor in the apical region of the lung. The Pancoast tumor is a malignant tumor. The authors note that radiography was necessary to acquire an accurate diagnosis and an appropriate referral.

•••••••••

In 1992, Owens published a study in the Journal of Manipulative and Physiological Therapeutics, titled (4):

Line drawing analyses of static cervical X-ray used in chiropractic

In this review article, Owens identifies the chiropractic techniques used to assess the structure of the cervical spine as seen on the static cervical radiograph. His data was accumulated from a search of MEDLINE using key words “radiograph and X ray in combination with cervical spine (vertebrae)”; the Chiropractic Research Archives Collection; indexes published in the Journal of Chiropractic Research; conference proceedings from the Annual Biomechanics Conference of the Spine, FCER sponsored conferences and the Annual Upper Cervical Spine Conference; references identified from bibliographies of pertinent articles; and a telephone poll of radiography/technique instructors at chiropractic colleges. He specifically looked at techniques that quantitatively assess relative alignment of skeletal structures or distortion of the spinal column, and the techniques were assessed for their reliability and validity.

“Reliability studies exist showing that inter- and intra-examiner reliability are sufficient to measure lateral and rotational displacements of C1 to within +/- 1 degree. This amount of error allows objective analysis of upper cervical x-rays to detect changes in the angular positional relationships of radiographic images on the order of those already seen clinically. Methods of cervical analysis that use relative angular measures of skeletal positioning are best able to control the effects of radiographic distortion.”

This study supports the utilization of upper cervical spine radiographs to determine the measureable biomechanics of atlas lateral and rotational displacements.

•••••••••

In 1995, John Taylor and colleagues from the Department of Radiology, University of California, Medical Center, San Diego, published a study in the journal Spine, titled (5):

Interpretation of abnormal lumbosacral spine radiographs:

A test comparing students, clinicians, radiology residents, and radiologists in medicine and chiropractic

This study was a controlled comparison of radiographic interpretive performance based on training and experience by these different disciplines and students. The authors tested their abilities to interpret abnormal plain film radiographs of the lumbosacral spine and pelvis. This study is the first to compare radiographic interpretations of students, clinicians, radiology residents, and radiologists.

The authors used 19 sets of radiographs with clinically important radiographic findings and had them interpreted by 496 volunteers, as follows:

• 183 chiropractic students
• 66 medical clinicians
  • 12 general practice physicians
  • 25 orthopedic surgeons
  • 21 orthopedic residents
  • 8 rheumatologists
• 55 chiropractic radiologists
• 48 general medical radiologists
• 46 chiropractic clinicians
• 36 skeletal radiologists and fellows
• 27 medical radiology residents
• medical students
• 13 chiropractic radiology residents

Percentage of Correct Diagnosis by Group

The authors discovered that in the interpretation of abnormal plain film radiographs of the lumbosacral spine and pelvis, significant differences were found among professional groups. Yet, the study also clearly showed that chiropractic radiologists, chiropractic radiology residents, chiropractic clinicians, and chiropractic students have comparative ability to interpret pathology of lumbar spine/pelvis radiographs as do their medical counterpart group.

•••••••••

In 1997, Assendelft and colleagues from the Institute for Research in Extramural Medicine, Amsterdam, published a study in the journal Spine, titled (6):

Reliability of lumbar spine radiograph reading by chiropractors

This study investigated the variability in the interpretation of lumbar spine radiographs by chiropractors working in private practice. The authors used 4 chiropractors to read 100-blinded sets of standard, upright antero-posterior and lateral lumbar radiographs.

The authors found that the interobserver and intraobserver agreement to be “fair to good,” which they judged to be “acceptable.”

•••••••••

Also in 1997, Harger and colleagues from the Department of Radiology, Western States Chiropractic College, Portland, Oregon, published a study in the Journal of Manipulative and Physiological Therapeutics, titled (7):

Chiropractic radiologists:
A survey of chiropractors’ attitudes and patterns of use

The objective of this study was to assess the chiropractic use of radiography, referral patterns to both medical and chiropractic radiologists and attitudes toward radiologists by 197 practicing U.S. chiropractors. Seventy-four percent of the respondents have radiographic facilities in their offices. The results gave the following reasons for taking radiographs:

71% To screen for contraindication to chiropractic care.

63% To assess existence of pathological conditions.

51% To observe/measure altered biomechanics and posture.

27% For medicolegal protection.

84% of the participating chiropractors refer to medical radiologists and/or to chiropractic radiologists for a formal interpretation of their radiographs.

85% of the participating chiropractors felt that chiropractic radiologists are as well qualified as medical radiologists in interpreting their radiographs.

•••••••••

The Chiropractic Biophysics, Inc., group prides itself on precision radiographic postural analysis of patients, both prior to and after following a protocol of structural rehabilitation. Starting in the 1990s they performed a series of studies whose objective was to establish the reliability and validity of their postural radiological measurements. Their blinded radiological analysis was assessed with the help of the Department of Statistics, Temple University, Philadelphia, PA. They were able to prove both the reliability and validity of their x-ray measurement systems for postural analysis (8, 9, 10, 11, 12).

•••••••••

In 2002, an important study was published in the journal Spine, titled (13):

Reliability and validity of lumbosacral spine radiograph reading by chiropractors, chiropractic radiologists, and medical radiologists

The authors were from the Department of Radiology, Medical Center Alkmaar, Alkmaar, The Netherlands. Their design was a cross-sectional diagnostic study. Their objective was to determine and compare the reliability and validity of contraindications to chiropractic treatment (infections, malignancies, inflammatory spondylitis, and spondylolysis/spondylolisthesis) detected by chiropractors, chiropractic radiologists, and medical radiologists on plain lumbosacral radiographs.

The authors acknowledge that plain radiography of the spine is an established part of chiropractic practice, but that few studies have assessed the ability of chiropractors to read plain radiographs.

Five chiropractors, three chiropractic radiologists and five medical radiologists read a set of 300 blinded lumbosacral radiographs, 50 of which showed an abnormality, in two sessions. The results were expressed in terms of reliability and validity.

The results were such that the authors concluded that the small differences between the groups were of “little clinical relevance.” The authors stated:

“All the professional groups could adequately detect contraindications to chiropractic treatment on radiographs. For this indication, there is no reason to restrict interpretation of radiographs to medical radiologists. Good professional relationships between the professions are recommended to facilitate interprofessional consultation in case of doubt by the chiropractors.”

•••••••••

Percentages change over the years. Presented evidence suggests that about 75% of chiropractors have x-ray available to them in their clinics. Additional chiropractors (myself included) that do not have x-ray available in their clinics have the ability to readily obtain x-rays. I do not have an x-ray machine in my office, but I refer patients for x-rays to the chiropractor who practices across the parking lot from my office.

The decision to take x-rays by some chiropractors is based upon specific aspects of individual case history or the presence of certain red flags. Yet, it appears that there is a large group of chiropractors, perhaps as high as 50% that take x-rays primarily for spinal biomechanical analysis reasons. These chiropractors often pride themselves on the accuracy of their exposure parameters and of their roentgenometric line analysis and measurements. Often, the chiropractor’s line-of-drive (adjustment) designed to correct the biomechanical distortion is based upon these biomechanical analysis. For example:

In 1992, an article published in the journal Manual Medicine by German physician Heiner Biedermann, MD, titled (14):

Kinematic Imbalances Due To Suboccipital Strain In Newborns

Dr. Biedermann is from the Surgical Department of the University of Witten-Herdecke, Germany. In this article he discusses the importance of the biomechanics of upper cervical spine in infants, especially as related to birth delivery stress. He details both the analysis and manual correction of these biomechanical problems. In the article he states [Biedermann Group]:

On these babies, “an A-P radiograph of the upper cervical spine is imperative.”

“The radiological evaluation helps to find malformations and aids in determining the direction of the manipulation.”

“In most cases the direction of the manipulation is determined by radiological findings (85%).”

“Selection of the direction of the treatment without x-ray seems the most plausible cause of the less encouraging results of some colleagues.”

The author determines the direction of the manipulation with an “exact evaluation of the lateral displacement of atlas and/or axis against the occiput.”

In 2007, a study from Rush University Hypertension Center in Chicago was published in the Journal of Human Hypertension, and titled (15):

Atlas vertebra realignment and achievement of arterial pressure goal in hypertensive patients

Once again, the authors used a careful and precise radiological analysis to determine the line-of-drive for manual correction of aberrant biomechanics of the upper cervical spine. The article includes these concepts [Dickholtz Group]:

Pre-Alignment Craniocervical Radiographs: Three X-ray views to measure in three dimensions the Atlas misalignments in precise degree of orientation.

On the radiographs, the “clinician locates physiological landmarks to mark pencil lines at ‘vertical axis’ (perfect Atlas alignment) and the center of the skull on the Nasium view, then uses a protractor to measure physiologic angles that deviate from them, view by view, in order to visualize, in three dimensions, the Atlas misalignment’s degree and orientation.”

“The hypothesis behind the Atlas adjustment suggests that misalignment involves either a displacement from an optimally centered location or a rotation away from an optimally angular orientation (as determined by X-ray).”

Interestingly, both the Biedermann Group (14) and the Dickholtz Group (15) insist that optimum clinical outcomes on their patient populations require careful exposure, analysis, and specific line-of-drive spinal adjusting based upon the x-ray analysis. Biedermann is a medical physician. Dickholtz is a chiropractor.

Chiropractors that expose x-rays on patients for biomechanical analysis also read the film for pathology and anomalies. Evidence suggests that chiropractors have fair to good, but not excellent, accuracy in reading x-rays for pathology. It is clear that both chiropractic or medical radiologists have significantly improved accuracy in pathology reading of x-rays. This suggests that chiropractors should often have questionable findings read by a certified radiologist. Even so, certified radiology reads only achieved an accuracy level of about 70%. Field practitioners who send their x-ray out to a radiologist for interpretation usually assume a 100% accuracy of the reading, but evidence indicates that is overly optimistic. This should be understood by field practitioners.

An apparent universal problem with the human brain is “inattentional blindness,” which is defined as “people often miss the occurrence of an unexpected yet salient event if they are engaged in a different task.” Many examples of this “inattentional blindness” phenomenon are found on the internet’s YOUTUBE, usually found under the words “invisible gorilla.” Interestingly, this “inattentional blindness” has recently (September 2013) been applied to the reading of radiology. In the journal Psychological Science published a study titled (16):

The invisible gorilla strikes again:
Sustained inattentional blindness in expert observers

The authors are from the Visual Attention Lab, Harvard Medical School, and Brigham and Women’s Hospital, Boston, Massachusetts. They note:

“Researchers have shown that people often miss the occurrence of an unexpected yet salient event if they are engaged in a different task, a phenomenon known as inattentional blindness.

However, demonstrations of inattentional blindness have typically involved naive observers engaged in an unfamiliar task. What about expert searchers who have spent years honing their ability to detect small abnormalities in specific types of images?

We asked 24 radiologists to perform a familiar lung-nodule detection task. A gorilla, 48 times the size of the average nodule, was inserted in the last case that was presented. Eighty-three percent of the radiologists did not see the gorilla. Eye tracking revealed that the majority of those who missed the gorilla looked directly at its location.

Thus, even expert searchers, operating in their domain of expertise, are vulnerable to inattentional blindness.”

Perhaps this explains the 70% accuracy rate in reading x-rays for pathology by trained radiology experts. It’s a phenomenon that all clinicians should be aware of.

References

1. Martin SC (1993); Chiropractic and the social context of medical technology; Technology and Culture, Vol. 34, No. 4; pp. 808–34.
2. Kovach SG; Huslig EL; Prevalence of diagnoses on the basis of radiographic evaluation of chiropractic cases; Journal of Manipulative and Physiological Therapeutics; December 1983; Vol. 6, No. 4; pp. 197-201.
3. Kovach SG; Huslig EL; Shoulder pain and Pancoast tumor: A diagnostic dilemma; Journal of Manipulative and Physiological Therapeutics; March 1984; Vol. 7, No. 1; pp. 25-31.
4. Owens EF; Line drawing analyses of static cervical X ray used in chiropractic; Journal of Manipulative and Physiological Therapeutics; September 1992; Vol. 15; No. 7; pp. 442-449
5. Taylor JA; Clopton P; Bosch E; MillerKA; Marcelis S; Interpretation of abnormal lumbosacral spine radiographs. A test comparing students, clinicians, radiology residents, and radiologists in medicine and chiropractic; Spine; May 15, 1995; Vol. 20; No. 5; pp. 1147-1153.
6. Assendelft WJ, Bouter LM, Knipschild PG, Wilmink JT; Reliability of lumbar spine radiograph reading by chiropractors; Spine; June 1, 1997; Vol. 22; No. 11; pp. 1235-1241.
7. Harger BL, Taylor JA, Haas M; Nyiendo J; Chiropractic radiologists: A survey of chiropractors’ attitudes and patterns of use; Journal of Manipulative and Physiological Therapeutics; June 1997; Vol. 20; No. 5; pp. 311-314.
8. Troyanovich SJ, Harrison DE, Harrison DD, Holland B, Janik TJ; Further analysis of the reliability of the posterior tangent lateral lumbar radiographic mensuration procedure: concurrent validity of computer-aided X-ray digitization; Journal of Manipulative and Physiological Therapeutics; September 1998; Vol. 21; No. 7; pp. 460-467.
9. Troyanovich SJ, Harrison SO, Harrison DD, Harrison DE, Payne MR, Janik TJ, Holland B; Chiropractic biophysics digitized radiographic mensuration analysis of the anteroposterior lumbopelvic view: a reliability study; Journal of Manipulative and Physiological Therapeutics; June 1999; Vol. 22; No. 5; pp. 309-315.
10. Troyanovich SJ, Harrison DE, Harrison DD, Holland B, Janik TJ; Chiropractic biophysics digitized radiographic mensuration analysis of the anteroposterior cervicothoracic view: a reliability study; Journal of Manipulative and Physiological Therapeutics; September 2000; Vol. 23; No. 7; pp. 476-482.
11. Harrison DE, Holland B, Harrison DD, Janik TJ; Further reliability analysis of the Harrison radiographic line-drawing methods: crossed ICCs for lateral posterior tangents and modified Risser-Ferguson method on AP views; Journal of Manipulative and Physiological Therapeutics; February 2002; Vol. 25; No. 2; pp. 93-98.
12. Harrison DE, Harrison DD, Colloca CJ, Betz J, Janik TJ, Holland B; Repeatability over time of posture, radiograph positioning, and radiograph line drawing: an analysis of six control groups; Journal of Manipulative and Physiological Therapeutics; February 2003; Vol. 26; No. 2; pp. 87-98.
13. de Zoere A, Assendelft WJ, Algra PR, Oberman WR, Vanderschueren GM, Bezemer PD; Reliability and validity of lumbosacral spine radiograph reading by chiropractors, chiropractic radiologists, and medical radiologists; Spine; September 1, 2002; Vol. 27; No. 17; pp. 1926-1933.
14. Biedermann H; Kinematic Imbalances Due To Suboccipital Strain In Newborns; Journal of Manual Medicine; June (No. 6) 1992, pp. 151-156.
15. Bakris G, DickholtzSr M, Meyer PM, Kravitz G, Avery E, Miller M, Brown J, Woodfield C, Bell B; Atlas vertebra realignment and achievement of arterial pressure goal in hypertensive patients: a pilot study; Journal of Human Hypertension; March 2,2007 (advanced e-publication).
16. Drew T, Vo ML, Wolfe JM; The invisible gorilla strikes again: sustained inattentional blindness in expert observers; Psychological Science; September 1, 2013; Vol. 24; No. 9; pp. 1848-1853.