The “discovery” of X-rays occurred in 1895 by German physicists Wilhelm Conrad Rontgen. Rontgen did not actually discover x-rays; he identified them. He named them “x-rays” because their exact nature was not yet identified. Much of the world refers to x-rays as “Rontgen Rays.” Rontgen was awarded the first Nobel Prize in physics for his discovery in 1901.

The first biological application for x-rays was when Rontgen made an x-ray of his wife’s hand. Rontgen immediately knew that x-rays would have medical applications.

History records that the chiropractic profession pioneered the use of x-rays on the spine in 1910 (1, 2). They called spinal x-rays “spinographs.”

Today, x-ray (radiology) is at the center of much of chiropractic education. Typical chiropractic curriculum has between 6-10 courses that are wholly dedicated to radiology. Additionally, radiology is woven into the majority of clinical science and technique courses. Consequently, leading scientific/medical journals have confirmed the competency of chiropractors in reading/interpreting spinal x-rays (3, 4, 5).

In 2002, a study was published in the journal Spine, titled (5):

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, The Netherlands. Their objective was to determine and compare the reliability and validity of contraindications to chiropractic treatment (infections, malignancies, inflammatory spondylitis, spondylolysis and spondylolisthesis) detected by chiropractors, chiropractic radiologists, and medical radiologists on plain lumbosacral radiographs. The authors acknowledge that x-rays of the spine are an established part of chiropractic clinical practice.

The participants of the study read a set of 300 blinded lumbosacral (lower back) radiographs, 50 of which showed an abnormality. The authors concluded that the small differences between the groups were of “little clinical relevance,” stating:

“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.”

An important inclusion in this study was that x-rays were used to determine contraindications to chiropractic care, including the presence of infections, malignancies, and inflammatory spondylitis.

The clinical use of x-rays in chiropractic clinical practice is very common. A study published in 1997 in the Journal of Manipulative and Physiological Therapeutics noted (6):

• 74%of chiropractors have x-ray facilities in their offices.
• 71%use x-rays to screen for contraindications to chiropractic care.
• 63% use x-rays to assess existence of pathological conditions.
• 51%use x-rays to observe/measure altered biomechanics and posture.
• 27%use x-rays for medico-legal protection.
• 84% of the chiropractors refer to medical radiologists and/or to chiropractic radiologists for a formal interpretation of their radiographs.

X-rays are particularly important in clinical practice when the patient presents with a history of trauma, such as whiplash-injury trauma. More than 100 years ago (1919) a study was published on this topic in the Boston Medical and Surgical Journal. The author, Herman W. Marshall, MD, noted (7):

“X-rays of cervical spines demonstrate their positive values in instances of dislocation, fracture, and of bone disease so often that it is needless to emphasize their great importance.”

Dr. Marshall notes that following trauma, initial x-rays may be considered normal, but that subsequent x-rays may show the healing of such fractures.

Marshall also noted that later x-rays (months later) can show hypertrophic changes increasing. He interprets this as meaning there is a local impairment in physiologic function of the affected tissues, and that such hypertrophic changes “are liable to increase as the result of the injury.”
Later x-rays, months after injury, may be valuable because they may show signs of an earlier missed fracture or they may show progression of degenerative disease.

He also notes that pre-injury degenerative spinal disease found on early post-traumatic x-rays indicates a weakness that results in increased injury from a given traumatic event.

In 1953, physicians James Gay, MD, and Kenneth Abbott, MD, published a study in the Journal of the American Medical Association, titled (8):

Common Whiplash Injuries of the Neck

These authors studied 50 whiplash-injured patients. Pertaining to x-rays, they note:

“The roentgen examination of the cervical spine was an important adjunct procedure in defining the pathology of the injury.”

They advocated taking 6 cervical radiographic views: anterior to posterior, lateral cervical, lateral-flexion, lateral-extension, left and right oblique views. When skull or low back injury was suspected, x-rays were taken of those regions as well.

Another study in 1953 by physician Harvey Billig, MD, was published in the Journal of the International College of Surgeons, titled (9):

Traumatic Neck, Head, Eye Syndrome

Dr. Billig noted that with traumatic neck injuries, early radiographs could show chip or compression fractures of the vertebral bodies. He also noted that post-traumatic cervical dorsal discs injuries “went on to the development of traumatic arthritic changes.”

If the facet joint ligaments were injured, radiographs would show anterior or posterior alignment subluxation. Billig specifically stated:

“In these cases, the subluxation usually did not materialize until six months or more after the date of trauma, so that it is well to remember that all injuries to the neck should be followed by periodic roentgenographic studies for several years after the injury, with this point in mind.”

In 1957, physician Kirk V. Cammack, MD, published a study in the American Journal of Surgery, titled (10):

Whiplash Injuries to the Neck

Dr. Cammack evaluated 50 consecutive whiplash cases that were hospital treated; 82% had long-term follow-up. Exposed radiographs found:

• 22% had a vertebral body compression fraction.
• 82% of the compression fractions were at the body of C5 or C6, indicating occurrence during the rebound flexion phase of whiplash.

In 1958, neurosurgeon Emil Seletz, MD published an article in the Journal of the American Medical Association, titled (11):

Whiplash Injuries: Neurophysiological Basis for
Pain and Methods Used for Rehabilitation

Dr. Seletz emphasizes the physiological and radiological importance of post-traumatic injury to the uncinate processes (joints of von Luschka). He notes that in whiplash injury, the joints of von Luschka play a very significant clinical role:

“With degenerative thinning of the disk after trauma, the processes of the lateral joints are gradually forced outward and laterally, resulting in osteophyte formation.”

“These spurs project even more, since the osteophytes are capped with cartilage and are considerably larger than is revealed by the roentgenogram.”

“The resultant faulty posture in neglected cases enhances the degeneration of the intervertebral disks, as well as spur formation in the lateral co-vertebral articulations, which on the roentgenogram has come to be known as traumatic arthritis.”

Dr. Seletz notes that lateral spurs from the joints of von Luschka compress the nerve root in the foramen. When slightly more anterior to the nerve root, joints of von Luschka spurs can encroach on the vertebral artery and the vertebral nerve (sympathetic) within the foramen transversarium.
In 1964, orthopedic surgeon and whiplash injury expert Ruth Jackson, MD, published a study in the American Journal of Orthopedics, titled (12):

The Positive Findings in Neck Injuries

After analyzing 5,000 motor vehicle collisions patients, Dr. Jackson stated:

“An adequate radiographic examination of the cervical spine is essential for diagnosis.”

Pre-existing pathological conditions of the cervical spine, when injured, “result in more damage than would be anticipated in a so-called ‘normal’ cervical spine.”

Dr. Jackson recommended that 8 x-rays be exposed following whiplash trauma, including lateral radiographs of the cervical spine in maximum flexion and extension to document segmental motion problems. She noted that x-rays showing “any segmental instability, any segmental restriction of motion, and any segmental angulation may indicate severe injury.”

Dr. Jackson also noted that initial x-rays may be normal, but subsequent x-rays may reveal multiple problems. Therefore, repeat x-rays are essential:

“All radiographs should be repeated periodically. Subsequent findings may be very revealing.”

“Repeated physical and radiographic examinations are necessary for final analysis.”

In 1993, Australian physicians JR Taylor, MD, and P Finch, MD, published a study in the Annals Academy of Medicine Singapore, titled (13):

Acute Injury of the Neck: Anatomical and Pathological Basis of Pain

Their paper focused on neck sprain from road traffic accidents as a cause of pain. Their data is compiled from literature review as well as autopsy and/or histology on their own 105 subjects.

These authors emphasize the value of maximum lateral cervical extension x-rays to detect a post-traumatic “rim lesion.” Rim lesions only occur as a consequence of trauma. They represent a traumatic disruption of the annular disk fibers from their attachment to the vertebral body. They are permanent injuries, only detectable with maximum extension x-rays. A positive finding is the presence of a gas shadow (vacuum cleft) in the disk. The authors state:

“Simple investigations such as extension X-rays may reveal vacuum clefts in the same anatomical position as rim lesions.”

In extension there is a typical “rim lesion,” which is an anterior distraction-shearing injury, “a transverse tear in the disc near the attachment of the anterior annulus to the vertebral rim.”

“In patients with extension injuries, vacuum clefts may be demonstrated in extension radiographs.”

In 2017, a study was published in the Mayo Clinic Proceedings, titled (14):

Influence of Initial Provider on Health Care Utilization
in Patients Seeking Care for Neck Pain

The authors compared and contrasted 5 different health care provider groups in the management of a new episode of neck pain in a retrospective cohort of 1,702 patients. The provider groups included:

• Primary Care Provider
• Physical Therapist
• Chiropractor
• Specialist (physiatrists or neurologist)

“These specific provider types were included in the analysis because they are the most common providers consulted for neck pain.” In every assessed parameter, chiropractic had the best outcomes.

These authors note that chiropractors are noted for the frequent use of spinal x-rays. Yet, they speculate that this increase in x-ray imaging may be responsible for the reduction of the use of advanced imaging, such as MRI and CT, resulting in a net benefit for both the patient and the reimbursing parties, saving the system money, time, and personnel resources.

In 2020, a study was published in the journal Quantitative Imaging in Medicine and Surgery, titled (15):

The Role of Radiography in the Study of Spinal Disorders

This article is a comprehensive review of the value and importance of standard spinal x-rays as the initial assessment for a variety of common congenital, degenerative, traumatic, infectious, metabolic, and carcinogenic spinal disorders. The authors state:

“Radiography plays an important role in many conditions affecting the spine.”

“Radiologists are increasingly unfamiliar with the typical findings in normal and pathologic conditions of the spine.”

“Clinicians and radiologists are losing their interest in interpreting radiographs, relying more in the source of information provided by tomographic techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI).”

“Because CT and MRI have displaced radiography in the study of many spinal conditions, radiographic signs of spinal conditions have become increasingly less studied and thus less known among clinicians and radiologists.”

“Radiographs are recommended as the initial imaging study in patients with history of low-energy trauma and in patients with suspicion of vertebral compression fracture, such as osteoporotic patients or those receiving steroids.”

“When persistent pain or red flags are present (e.g., fever, trauma, history of malignancy), radiography is still considered the first imaging modality.”

The authors note that the most frequent origin of spinal pain is classified as “non-specific” (approximately 70%) because the specific nociceptive source cannot be identified. The second most prevalent cause of spinal pain is mechanical. Mechanical spinal pain includes degenerative disorders of the spine, alignment abnormalities, and vertebral fractures. X-rays are very valuable in diagnosing mechanical causes of back pain.

Back pain may also be secondary to specific causes, such as infection, inflammatory, or tumors, etc. X-rays are also very valuable in diagnosing these specific causes of back pain and hence they are recommended.

These authors advocate spinal x-rays for the assessment of these categories:

• Traumatic Fracture
• Congenital Abnormalities
• Osteoporotic Vertebral Fracture
• Degenerative Spinal Pathology
• Spinal Instability
• Spondylolisthesis
• Alterations in Spinal Curvature
• Inflammatory Pathology
• Infectious Pathology
• Neoplastic Pathology

Traumatic Fracture

Traumatic fractures are readily viewed on spinal x-rays. When fracture is suspected by history and examination, x-rays are the imaging modality of choice.

A vertebral body fracture is considered unstable if the posterior height of the vertebral body (a burst fracture) is reduced (lateral view), or when there is a widening of the interpedicular distance (AP view), or a widening of the interspinous distance (AP view). Sometimes on the AP view, a horizontal fracture line may be seen through a pedicle. The authors insist that:

“CT must be performed even after detection of a vertebral fracture in radiographs.”

Congenital Abnormalities

Congenital pathologies are easily identified with x-rays, including:

• Kyphosis
• Lordosis
• Scoliosis
• Congenital vertebral anomalies (agenesis, hemi-vertebrae, wedged or butterfly vertebrae), block vertebrae, Klippel-Feil, etc.
• Transitional vertebra (present in <25% of the population)
  • Sacralization of L5 which is fused to the sacrum
  • Lumbarization in which S1 is detached from the sacrum

Osteoporotic Vertebral Fracture

Osteoporosis is a systemic skeletal disease characterized by a reduction in bone mass “leading to increased bone fragility and fracture risk.” These fragility fractures primarily occur in the vertebral column. A vertebral fracture after minor trauma is a hallmark of osteoporosis.

Osteoporotic vertebral fractures have a high prevalence in the elderly. They affect at least 25% of all postmenopausal women, and is commonly seen among women approximately one decade after menopause. The prevalence of osteoporotic vertebral fracture in elderly men is about half of that in age-matched women.

The most frequent site of osteoporotic vertebral fracture is the thoracolumbar junction. The second most frequent region is the mid-thoracic spine.

Many osteoporotic vertebral fractures go undiagnosed because they are often relatively asymptomatic.

When symptomatic, patients often report sudden or acute onset of back pain in temporal relationship with relatively nontraumatic activities such as bending forward, standing from a seated position, or even with vigorous coughing or sneezing.

Smoking and alcohol use increase the risk for osteoporotic fractures.

Degenerative Pathology

Degenerative pathology of the spine can affect the synovial joints, atlantoaxial joints, facets, disk, costovertebral and sacroiliac joints. They are exceptionally common in all adult age groups, and their incidence increases with age (16). Disc degeneration in particular is found in nearly 100% of persons in their 8th decade, yet such degenerative pathology is often asymptomatic (16).

Disc degeneration is characterized by “narrowing of the intervertebral disc space, central vacuum phenomenon, sclerosis of the vertebral endplates and subchondral bone, and asymmetric osteophytes in any direction.” Disc degeneration is best viewed with lateral x-rays in the cervical, thoracic, and lumbar spines.

Facet joint degeneration in both the cervical and lumbar spines is best viewed with oblique x-rays.

Degenerative changes of the cervical spine will usually also involve the uncovertebral processes (uncinate processes), with formation of posterior osteophytes. Cervical oblique x-rays are best to visualize uncinate osteophytes and any foraminal stenosis. AP x-rays may show uncinate flattening with sclerosis. On lateral cervical x-rays, uncinate degeneration may show a line that leads to the false impression of a fracture.

Degenerative bone-related central canal stenosis is best visualized on the lateral x-ray in both the cervical and lumbar spines.

At the cervical level (72-inch film distance), a “sagittal canal diameter <14 mm between C4 and C7 or a ratio between the sagittal diameter of the canal and that of the vertebral body <0.8 is considered signs of central canal stenosis.”

In the lumbar spine exposed at 40 inches, “moderate stenosis is established if the sagittal diameter is between 10 and 14 mm and severe stenosis if the diameter is <10 mm.”

Diffuse Idiopathic Skeletal Hyperostosis “DISH” is a “systemic
condition, with an estimated prevalence of approximately 10% in people >50 years of age.” It is considered to be degenerative in nature. The diagnosis is made in the presence of large bridging osteophytes affecting adjacent vertebrae. Patients with DISH “may be largely asymptomatic.”
The spinal stiffness associated with the disease implies increased “spinal vulnerability to low-energy trauma.”

Instability

Stress x-rays, especially lateral flexion and extension x-rays are useful in assessing spinal stability and to diagnose post-traumatic instability.

For the lumbar spine, sagittal rotation exceeding 10° between segments, measured as the shift of the angle between the vertebral endplates, indicates instability. If there is more than 3 mm of sagittal translation, that segment is also instable.

For cervical spine instability, a 3-mm slippage is a reliable cut-off point.

For the atlantoaxial joint, the accepted criteria with flexion-extension radiographs is an interval “greater than 3 mm between the anterior margin of the odontoid process and the posterior cortex of the anterior arch of the atlas.”

Spondylolisthesis

X-rays are excellent in diagnosing all 6 types of spondylolisthesis: congenital/dysplastic, isthmic, traumatic, pathologic, iatrogenic, and degenerative.

Isthmic spondylolisthesis is the most frequent type of spondylolisthesis and is generally considered to be a stress fracture at the pars interarticularis. This fracture is adequately visualized with a lateral lumbar x-ray spot shot or with oblique x-rays. The oblique view provides better definition of the isthmic defect, showing a silhouette resembling a ‘dog’ known as the ‘Scotty dog’. Demonstration of ‘the collar or broken neck of the Scotty dog’ sign indicates isthmic spondylolisthesis.

Degenerative spondylolisthesis is secondary to facet and disc degeneration, so the vertebral neural arch remains intact. Degenerative spondylolisthesis is the “most frequent cause of spondylolisthesis in elderly subjects.”

Traumatic spondylolisthesis is a rare injury, and defined as an acute fracture or dislocation of the posterior elements associated with vertebral spondylolisthesis. “Traumatic spondylolisthesis at C2 is called the ‘Hangman’s Fracture’.”

Retrolisthesis is a “posterior shifting of a cephalad vertebra over caudal vertebra.” Retrolisthesis is generally secondary to loss of disc material caused by disc degeneration.

Alterations in Spinal Curvature

Full-spine x-rays are “essential in assessing coronal alignment and sagittal balance after fracture, in congenital or developmental abnormalities with associated deformity (scoliosis and kyphosis), or in deformity secondary to degenerative disorders.”

X-rays “play a key role in the diagnosis and management of abnormal spine curvature, including scoliosis and kyphosis.” Vertebral alignment and spinal curvatures can be readily assessed and measured using full-spine x-rays.

During adolescence, juvenile kyphosis (Scheuermann’s disease), will cause pathological kyphosis. Scheuermann’s disease is characterized by irregular endplates, Schmorl nodes, and narrowing of the intervertebral disc.

“Scoliosis is defined as a lateral curvature of the spine greater than 10° when measured on a standing radiograph according to the Cobb method.” In adolescent scoliosis, x-rays are used to monitor for curve progression.
Inflammatory Pathology

X-rays are still recommended as initial examination to rule out inflammatory diseases such as ankylosing spondylitis, inflammatory bowel disease bony changes, and psoriatic arthritis.

Infectious Pathology

X-ray findings in osteomyelitis include “destruction of two adjacent vertebral endplates with narrowing or disappearance of the disc space.”

Neoplastic Pathology

Tumors of the spine may be metastatic, primary benign or primary malignant.

“Metastatic lesions can manifest on radiographs with an osteolytic, osteoblastic, or mixed pattern.” Between 30–50% of bone destruction is needed before the lesions become visible on x-rays. Destruction of the pedicle indicates that the lesion is advanced. Metastases from breast and prostate cancer present with a sclerotic pattern.

Hemangiomas are one of the most frequent benign tumor lesions seen in the spine, with a classic “corduroy cloth” pattern.

Multiple myeloma is characterized by lytic bone lesions that can result in pathologic fractures and severe pain. “Vertebral fractures are reported in 50–70% of patients with multiple myeloma.” The radiographic appearance of multiple myeloma may resemble that of osteoporotic vertebral fractures.

These authors conclude:

“If the clinical history, physical examination, and radiographs do not lead to any specific diagnosis, MRI is advocated as the next diagnostic exam because of its high sensitivity to depict the spinal and paraspinal soft tissues, disc and vertebral abnormalities associated to back pain.”

There are many benefits for both the chiropractor and patient to having spinal x-rays to assist in the analysis, diagnosis, and treatment of spinal syndromes.

REFERENCES

1. Young KJ; Evaluation of Publicly Available Documents to Trace Chiropractic Technique Systems That Advocate Radiography for Subluxation Analysis: A Proposed Genealogy; Journal of Chiropractic Humanities; December 2014; Vol. 21; No. 1; pp. 1–24.
2. Jenkins HJ, Downie AS, Moore CS, French SD; Current evidence for spinal X-ray use in the chiropractic profession: A narrative review; Chiropractic & Manual Therapies; November 21, 2018; Vol. 26; No. 48.
3. Taylor JA; Clopton P; Bosch E; Miller KA; 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.
4. 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.
5. de Zoete 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.
6. 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.
7. Marshall, HW; Neck Injuries; Boston Medical and Surgical Journal; January 23, 1919; Vol. 180; No. 4; pp. 93-98.
8. Gay JR, Abbott KH; Common Whiplash Injuries of the Neck; Journal of the American Medical Association; August 29, 1953; Vol. 152; No. 18; pp. 1698-1704.
9. Billig H; Traumatic Neck, Head, Eye Syndrome; Journal of the International College of Surgeons; November 1953; Vol. 20; No. 5; pp. 558-561.
10. Cammack KV; Whiplash Injuries to the Neck; American Journal of Surgery; April 1957; Vol. 93; pp. 663-666.
11. Seletz E; Whiplash Injuries: Neurophysiological Basis for Pain and Methods Used for Rehabilitation; Journal of the American Medical Association; November 29 1958; pp. 1750 – 1755.
12. Jackson R; The Positive Findings In Neck Injuries; American Journal of Orthopedics; August-September; 1964; pp. 178-187.
13. Taylor JR, Finch P; Acute Injury of the Neck: Anatomical and Pathological Basis of Pain; Annals Academy of Medicine Singapore; March 1993; Vol. 22; No. 2; pp. 187-192.
14. Horn ME, George SZ, Fritz JM; Influence of Initial Provider on Health Care Utilization in Patients Seeking Care for Neck Pain; Mayo Clinic Proceedings: Innovations, Quality & Outcomes; October 19, 2017; Vol. 1; No. 3; pp. 226-233.
15. Santiago FR, Ramos-Bossini AJL, Wáng YXJ, Zúñiga DL; The Role of Radiography in the Study of Spinal Disorders; Quantitative Imaging in Medicine and Surgery; 2020; Vol. 1; No. 12; pp. 2322-2355.
16. Brinjikji W, Luetmer PH, Comstock B, Bresnahan BW, Chen LE, Deyo RA, Halabi S, Turner JA, Avins AL, James K, Wald JT, Kallmes DF, Jarvik JG; Systematic Literature Review of Imaging Features of Spinal Degeneration in Asymptomatic Populations; American Journal of Neuroradiology (AJNR); April 2015; Vol. 36; No. 4; pp. 811–816.

“Authored by Dan Murphy, D.C.. Published by ChiroTrust® – This publication is not meant to offer treatment advice or protocols. Cited material is not necessarily the opinion of the author or publisher.”