Transverse Foramen
The transverse foramen is a small, round opening found in the cervical vertebrae (the bones in your neck). When this term appears on a radiology report, it usually refers to the area being evaluated for abnormalities involving the bones, arteries, or surrounding soft tissues. These foramina are important because they provide a pathway for the vertebral arteries, which supply blood to the brain. Understanding what the transverse foramen is and why it matters on imaging can help patients feel more informed when reviewing their results.
Where Is the Transverse Foramen Located?
Each cervical vertebra (C1 through C7) has a pair of transverse foramina—one on the left and one on the right. These holes are located in the transverse processes, the side portions of the vertebral bones. They are not present in thoracic or lumbar vertebrae, making them unique to the neck region.
What Travels Through the Transverse Foramina?
The vertebral arteries pass through these foramina from C6 up to C1 before entering the skull to help form the basilar artery. Alongside the vertebral arteries are veins and sympathetic nerve fibers. Any condition that affects this area can potentially impact blood flow to the brain or cause neurologic symptoms.
Why Is the Transverse Foramen Evaluated on Imaging?
Radiologists look at the transverse foramina when reviewing CT scans or MRIs of the neck and cervical spine. This evaluation is especially important when patients have symptoms like dizziness, neck pain, weakness, or signs of stroke. Any narrowing, asymmetry, or obstruction can suggest underlying pathology.
Common reasons transverse foramina are evaluated include:
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Vertebral artery compression or dissection
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Fractures involving the cervical spine
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Degenerative changes
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Congenital anomalies
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Tumors or masses encroaching on the foramen
Imaging Modalities That Show the Transverse Foramen
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CT Scan (Computed Tomography): Excellent for assessing bone detail. A CT can show fractures, bony narrowing of the foramina, or tumors pressing on the space. A CT angiogram can also assess the vertebral arteries.
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MRI (Magnetic Resonance Imaging): Better for soft tissue detail. MRI is used to assess vertebral arteries, surrounding nerves, inflammation, and tumors. MR angiography can visualize blood flow without contrast in some cases.
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Ultrasound (Doppler of the vertebral arteries): Sometimes used to assess blood flow, but limited in viewing the actual foramen itself.
Common Findings Involving the Transverse Foramen
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Asymmetric Transverse Foramina: Sometimes one foramen is smaller than the other. This can be normal or may reflect compression or congenital narrowing. If the vertebral artery on that side is also small, it may be an incidental finding.
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Foraminal Narrowing or Stenosis: Seen with degenerative changes, such as bone spurs or arthritis. This can compress the artery or nerve roots.
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Fracture Involvement: Fractures of the cervical vertebrae involving the transverse process can extend into the foramen and damage the vertebral artery.
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Vertebral Artery Dissection: If a tear occurs in the wall of the artery as it passes through the foramen, it can lead to stroke symptoms. MRI or CT angiography is used to diagnose this.
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Tumors or Metastases: Lesions near the transverse foramen may compress the artery or invade the foramen. Imaging helps detect such changes early.
Transverse Foramen Variants and Normal Differences
It’s common to see some anatomical variation in transverse foramina. For instance, the foramen may be incomplete or duplicated. In some people, the vertebral artery may enter the spine higher or lower than usual, which might be noted by the radiologist. These are often harmless but are important for surgeons and interventionalists to know.
What Should You Do If Your Report Mentions the Transverse Foramen?
If your imaging report mentions something involving the transverse foramen, review the findings with your doctor. Often it’s an incidental observation without clinical concern, especially if you’re not having related symptoms. However, if there’s evidence of compression, narrowing, or involvement by disease, further evaluation or follow-up imaging might be recommended.
Surgical or Interventional Relevance
In spine surgery or interventional procedures like cervical injections, knowledge of the location and size of the transverse foramina is important to avoid damaging the vertebral arteries. Radiologists may comment on variations or anomalies that could impact procedural planning.
Conclusion
The transverse foramen is a structure in the cervical spine that allows blood vessels to safely pass through the neck to the brain. Radiologists often assess this area for fractures, narrowing, or disease. Most findings are benign or incidental, but some may require attention, especially if symptoms are present. Your doctor will best determine whether a finding involving the transverse foramen is something that needs further evaluation and treatment.
References
https://pmc.ncbi.nlm.nih.gov/articles/PMC4581543/
https://pmc.ncbi.nlm.nih.gov/articles/PMC10572231/
https://radiopaedia.org/articles/accessory-transverse-foramen?lang=us