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Topic

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Transverse foramen

The transverse foramen is a bony canal located within the transverse processes of cervical vertebrae (C1–C7). It provides a protective passageway for the vertebral artery, vertebral vein, and sympathetic nerve fibers as they ascend toward the cranial cavity. In C1 (atlas) and C2 (axis), the transverse foramen is larger and slightly oblique, accommodating the vertebral artery’s course. C7 may have a smaller or absent transverse foramen, typically transmitting only a small vein.

The transverse foramen forms a critical anatomical landmark in cervical spine imaging, surgery, and trauma assessment, ensuring safe evaluation of vertebral artery patency, cervical fractures, or anomalies such as foraminal narrowing or congenital variation.

Function

  • Encases and protects the vertebral artery and vein

  • Provides a pathway for sympathetic nerve fibers

  • Maintains cervical spine vascular integrity

  • Serves as an important anatomical landmark for spinal procedures and imaging

  • Supports blood flow to the posterior brain

Synonyms

  • Foramen transversarium

  • Vertebral foramen of cervical transverse process

  • Transverse cervical canal

MRI Appearance

T1-weighted images:

  • The transverse foramen appears as a small, round to oval hypointense bony canal within the transverse process

  • The vertebral artery within the foramen is intermediate to slightly hyperintense, depending on flow and imaging parameters

  • Surrounding bone marrow in the transverse process is high signal intensity, providing clear contrast

T2-weighted images:

  • Bony margins of the foramen are low signal intensity (hypointense)

  • Vertebral artery lumen appears flow void (very low signal) due to rapid blood flow

  • Slow-flowing blood, thrombus, or pathology may appear hyperintense, highlighting vascular abnormalities

STIR (Short Tau Inversion Recovery):

  • Cortical bone remains low signal

  • Edema, inflammation, or fractures around the transverse foramen appear hyperintense

  • Useful for trauma, osteomyelitis, or inflammatory lesions

CT Appearance:

  • Transverse foramen is visualized as a round to oval, well-corticated bony canal within the transverse process

  • High-density cortical bone forms its margins

  • Internal lumen may be visible on high-resolution CT angiography, showing vertebral artery course

  • CT is excellent for fracture assessment, congenital variations, and foraminal stenosis

MRI images

Transverse foramen mri axial image

MRI image

Transverse foramen