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External jugular vein

The external jugular vein is a prominent superficial vein of the neck, easily visible and palpable in certain clinical conditions. It serves as a major venous drainage pathway for the head and neck, channeling blood from the scalp and face into the subclavian vein. Due to its superficial course, the external jugular vein is commonly visualized on physical examination, especially when venous pressure is elevated. Its appearance and characteristics on imaging modalities such as MRI, CT, and CTA are clinically relevant for diagnosing vascular disorders, trauma, and evaluating venous patency.

Synonyms

  • Vena jugularis externa

  • EJV

  • External cervical vein (less commonly used)

Function

  • Drains venous blood from the scalp, face, and superficial neck structures

  • Transports blood into the subclavian vein

  • Serves as an anatomical landmark for central venous access and emergency venous cannulation

  • Plays a role in clinical assessment of jugular venous pressure (JVP)

MRI Appearance

  • T1-Weighted Images:

    • The vein lumen appears as a low signal (dark) structure due to the flow void of blood.

    • Vessel wall may be slightly higher in signal if surrounded by subcutaneous fat.

  • T2-Weighted Images:

    • The lumen also appears as a flow void (dark), though sometimes may show intermediate signal if slow flow or partial volume effects occur.

    • Thrombosed segments may appear as hyperintense (bright) areas within the vessel.

  • STIR (Short Tau Inversion Recovery):

    • The normal vessel lumen remains low signal (dark).

    • Perivascular edema or inflammation is hyperintense (bright) on STIR, helping identify vessel wall pathology.

  • Post-Contrast T1 Fat-Saturated:

    • The vein lumen typically enhances if blood flow is present, appearing hyperintense (bright).

    • Thrombus within the vein will not enhance and may appear as a filling defect.

    • Fat suppression improves vessel-to-background contrast, highlighting vessel wall enhancement if present.

CT Appearance

  • Non-Contrast CT:

    • The external jugular vein appears as a tubular, hypoattenuating (dark) structure in the subcutaneous tissue lateral to the sternocleidomastoid muscle.

    • May be collapsed or small in size, especially if patient is hypovolemic.

  • CT Venography / CTA (CT Angiography):

    • Opacified vein is well-visualized as a contrast-enhanced structure, allowing assessment of patency, caliber, and any intraluminal thrombus (seen as a filling defect).

MRI images

External jugular vein axial mri image