Spinous Process
The spinous process can be mentioned in X-ray, CT or MRI studies of the spine. This bony projection extends from the back of each vertebra in your spine and serves several important functions in your body’s structure and movement. Understanding what radiologists mean when they reference the spinous process can help you have more informed discussions with your doctor.
What Is the Spinous Process?
The spinous process is the bony projection that extends posteriorly (toward your back) from each vertebra in your spine. These are the bumps you can feel when you run your fingers down someone’s back along the midline. Each vertebra in your spine—from the neck (cervical) to the lower back (lumbar)—has one spinous process, though they vary in size, shape, and angle depending on their location.
Anatomy and Function of the Spinous Process
The spinous processes serve as attachment points for muscles and ligaments that help stabilize and move your spine. They act as levers that muscles can pull on to create movement or maintain posture. Additionally, they protect the spinal cord by forming part of the posterior boundary of the spinal canal.
In the cervical (neck) region, spinous processes are often short and bifid (split into two). In the thoracic (mid-back) region, they tend to be longer and angle downward. In the lumbar (lower back) region, they are typically shorter, thicker, and project more horizontally.
Common Findings Related to the Spinous Process on Imaging
Fractures and Trauma
Spinous process fractures may appear on imaging following trauma. These fractures are often caused by direct impact, forceful muscle contraction, or as part of more complex spinal injuries. On radiographs or CT scans, radiologists might note “fracture of the spinous process of C7” or “avulsion of the spinous process of T4.”
This finding often indicates significant force was applied to the back, though isolated spinous process fractures generally have a favorable prognosis compared to other spinal fractures. Patients typically experience localized pain, tenderness, and may need restricted activity and pain management rather than surgical intervention.
Degenerative Changes
Age-related wear and tear can affect the spinous processes. Reports might mention “hypertrophy of the spinous process” or “osteophyte formation on the spinous process.” These changes may contribute to conditions like spinal stenosis (narrowing of the spinal canal) or potentially impact nearby nerves.
Alignment Issues
Radiologists often assess the alignment of spinous processes to evaluate spinal curvature. Terms like “spinous process deviation,” “rotation,” or “offset” may indicate conditions such as scoliosis or rotational malalignment of the spine.
Spinous Process in Different Imaging Modalities
X-rays and the Spinous Process
On standard X-rays, spinous processes appear as projections extending backward from each vertebra. Lateral (side) views show them as hook-like projections, while on anterior-posterior (front-to-back) views, they appear as oval densities superimposed on the vertebral bodies. Radiologists look for proper alignment, symmetry, and any abnormal appearances.
CT Scans and the Spinous Process
CT scans provide detailed cross-sectional images that can show fractures, degenerative changes, or abnormal growths affecting the spinous processes with greater clarity than X-rays. They’re particularly useful for evaluating trauma.
MRI and the Spinous Process
MRI are best at showing soft tissues around the spinous processes, including muscles, ligaments, and any inflammation. This can be valuable for diagnosing conditions like interspinous ligament sprains or evaluating for infection or tumors involving these structures.
Clinical Significance of Spinous Process Findings
Pain Generators
The interspinous ligaments and muscles attached to spinous processes can become painful due to injury or inflammation. Conditions like “kissing spine” (Baastrup’s disease), where adjacent spinous processes rub against each other, may be noted in radiology reports as a potential source of back pain.
Surgical Landmarks
Surgeons use spinous processes as important anatomical landmarks during spine procedures. Your radiologist might provide detailed descriptions of these structures to help guide surgical planning, particularly for minimally invasive approaches.
Reference Points for Procedures
The spinous processes serve as palpable reference points for spinal injections, including epidural steroid injections and facet joint blocks. Accurate imaging of these structures helps ensure proper needle placement during these procedures.
When to Be Concerned About Spinous Process Findings
While many findings related to spinous processes are incidental or minor, certain situations warrant further attention:
- Fractures following trauma, especially if accompanied by neurological symptoms
- Erosions or destruction of the spinous process, which might indicate infection or tumor
- Significant malalignment that could suggest instability
- Excessive bone growth (hypertrophy) that might be compressing neural structures
Radiologists typically note these concerns specifically in their reports and may recommend further imaging or specialist consultation.
Conclusion
Spinous process abnormalities on imaging studies range from incidental observations to significant pathology requiring treatment. Fractures, degenerative changes, and alignment issues of spinous processes directly correlate with clinical symptoms and functional outcomes. Discuss any spinous process findings in your radiology report with your doctor to determine clinical relevance and appropriate management. Treatment decisions should be based on both imaging findings and clinical presentation.
References
- https://www.mdpi.com/2079-9721/12/12/302
- https://hughston.com/wellness/spinous-process-fractures/
- https://www.ajronline.org/doi/10.2214/AJR.10.5803