Jugular Foramen
The jugular foramen is a small but important opening in the base of the skull. When it appears on your radiology report, it usually refers to something seen on a CT or MRI scan of the head or neck. Understanding what this area is and what can go wrong with it helps patients and families better interpret imaging findings and medical advice.
This article explains the jugular foramen using simple language. We’ll cover what it looks like on imaging, what structures pass through it, and what types of abnormalities may be found in this area on radiology scans.
Where Is the Jugular Foramen Located?
The jugular foramen is found at the base of the skull, behind the ear, where the skull bone meets the spine. There are two jugular foramina—one on the left and one on the right. Each forms a channel between the brain and the neck.
On imaging, radiologists look for this opening on axial (horizontal) CT or MRI views of the skull base. It appears as a small, oval-shaped hole just lateral to the internal auditory canal and anterior to the sigmoid sinus groove.
What Passes Through the Jugular Foramen?
Several important structures travel through the jugular foramen:
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Internal jugular vein: Carries blood away from the brain
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Cranial nerves IX (glossopharyngeal), X (vagus), and XI (spinal accessory): These control swallowing, speech, and some neck and shoulder movements
Because of these structures, problems in the jugular foramen can cause neurological symptoms, especially affecting the throat, voice, and shoulder.
How Is the Jugular Foramen Evaluated on Imaging?
Radiologists use CT and MRI scans to evaluate the jugular foramen:
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CT Scan: Best for evaluating bone detail. It shows the shape, size, and margins of the foramen. CT can also detect bone erosion or enlargement caused by masses or infections.
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MRI Scan: Best for evaluating soft tissues like nerves, vessels, and tumors. MRI is helpful for detecting nerve compression, abnormal growths, or inflammation.
When evaluating the jugular foramen, radiologists often compare the left and right sides to check for asymmetry.
Normal Variations of the Jugular Foramen
It’s common for one jugular foramen to be larger than the other. Usually, the larger one corresponds to the dominant internal jugular vein. This is considered a normal anatomical variation.
Radiologists note this asymmetry on reports to reassure referring doctors that it’s not a sign of disease.
Common Findings Involving the Jugular Foramen
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Jugular Foramen Tumors
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These are often glomus jugulare tumors (paragangliomas), schwannomas, or meningiomas.
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They may cause hearing loss, hoarseness, swallowing problems, or shoulder weakness.
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On imaging, they may appear as enhancing masses expanding the jugular foramen, sometimes with bony erosion.
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Jugular Foramen Schwannomas
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These tumors arise from cranial nerves IX, X, or XI.
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They are usually slow-growing and benign.
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MRI shows them as well-defined enhancing masses.
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Glomus Jugulare Tumors (Paragangliomas)
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These tumors arise from paraganglionic tissue in the jugular foramen.
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They are highly vascular, so they light up strongly with contrast on MRI.
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CT may show a “moth-eaten” bone appearance from erosion.
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Meningiomas
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These arise from the meninges (brain coverings) near the foramen.
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They often show a broad-based attachment and may cause bony thickening or hyperostosis on CT.
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Infections and Inflammation
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In rare cases, infection (osteomyelitis) or inflammatory disease can involve this region.
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MRI may show enhancement and swelling around the foramen.
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Symptoms That May Be Linked to Jugular Foramen Issues
If something abnormal is found in this area, symptoms may include:
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Hoarseness or voice changes (vagus nerve involvement)
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Difficulty swallowing (glossopharyngeal nerve involvement)
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Shoulder droop or weakness (spinal accessory nerve involvement)
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Pulsatile tinnitus (a whooshing sound in the ear, seen with glomus tumors)
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Headaches at the skull base or neck pain
When to Worry About Asymmetry
Most of the time, a difference in jugular foramen size is not concerning. But if it is accompanied by a mass, nerve compression, or bone destruction, further evaluation is needed. MRI with contrast is the best tool to see soft tissue details, and CT can confirm any bone changes.
Radiologists will mention any concerning findings and usually recommend a follow-up or additional imaging when needed. Sometimes they may suggest a referral to a neurosurgeon or ENT specialist.
What Happens Next if There’s a Mass?
If a tumor or lesion is found, your doctor may order:
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MRI with contrast: To better define the lesion
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CT angiography: To see blood vessels if the lesion is vascular
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Biopsy or surgical consultation: If the lesion needs tissue diagnosis or removal
Not all lesions need surgery. Some slow-growing tumors are monitored over time with follow-up imaging.
Conclusion
The jugular foramen is a key structure that appears on head and neck imaging. Most of the time, it’s a normal anatomic structure with side-to-side differences. But in some cases, abnormalities like tumors or infections can affect it, and radiologists carefully examine it on CT and MRI scans.
If you see “jugular foramen” on your report, it may just be describing normal anatomy. But if there’s a concern, your doctor will guide you through further tests or treatment. Understanding this area can help you feel more informed when reviewing your imaging results or discussing next steps with your doctor.
Relevant Resources
https://pmc.ncbi.nlm.nih.gov/articles/PMC7051696/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2637573/
https://pubs.rsna.org/doi/10.1148/radiographics.17.5.9308106