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Subclavian artery

The subclavian artery is a paired major artery that supplies blood to the upper limbs, neck, and brain. It arises asymmetrically: on the right, from the brachiocephalic trunk; on the left, directly from the aortic arch. The artery courses laterally across the root of the neck, arching over the first rib, where it continues as the axillary artery at the lateral border of the first rib.

The subclavian artery is conventionally divided into three parts by its relationship to the scalenus anterior muscle:

  • First part: medial to scalenus anterior

  • Second part: posterior to scalenus anterior

  • Third part: lateral to scalenus anterior until the outer border of the first rib

It gives rise to several important branches, including the vertebral artery, internal thoracic artery, thyrocervical trunk, costocervical trunk, and dorsal scapular artery (variable). Through these branches, it supplies the brain, spinal cord, thoracic wall, thyroid gland, and upper limb. The subclavian artery is clinically important due to its role in thoracic outlet syndrome, atherosclerotic disease, trauma, and endovascular interventions.

Synonyms

  • Arteria subclavia

  • Subclavian trunk

  • Preaxillary artery

Function

  • Supplies arterial blood to the upper limbs via the axillary artery continuation

  • Provides major blood supply to the brain and spinal cord via the vertebral arteries

  • Contributes to perfusion of the thoracic wall, thyroid, larynx, and scapular region through its branches

  • Forms part of the collateral circulation in the chest, shoulder, and cervical regions

Branches

  • First part: vertebral artery, internal thoracic artery, thyrocervical trunk

  • Second part: costocervical trunk

  • Third part: dorsal scapular artery (variable, may also arise from transverse cervical artery)

MRI Appearance

T1-weighted images:

  • Lumen appears as a flow void (black signal) due to fast-flowing blood

  • Vessel wall appears as a thin hypointense rim, surrounded by hyperintense fat planes

  • Useful for anatomical localization and relation to brachial plexus, scalene muscles, and subclavian vein

T2-weighted images:

  • Blood flow continues to appear as a signal void

  • Abnormalities (e.g., thrombosis, aneurysm, dissection) may appear as areas of altered signal intensity

  • Perivascular edema appears hyperintense

STIR (Short Tau Inversion Recovery):

  • Fat suppression improves delineation of vascular course through the neck and thoracic outlet

  • Wall edema, hematoma, or inflammatory changes appear hyperintense

  • Useful for trauma or vasculitis evaluation

T1 Post-Contrast (Gadolinium-enhanced):

  • Subclavian artery and branches show bright homogeneous enhancement

  • Clearly demonstrates stenosis, aneurysm, dissection, or vascular malformations

  • Essential for MR angiography (MRA) of thoracic outlet and cervicothoracic circulation

CT Appearance

Non-contrast CT:

  • Appears as a tubular soft tissue density near the thoracic inlet

  • Lumen is not clearly defined without contrast unless calcified plaques are present

CT Angiography (CTA):

  • Provides excellent visualization of origin, course, and branching pattern

  • Demonstrates stenosis, occlusion, aneurysm, dissection, or anomalous origins (e.g., aberrant right subclavian artery)

  • Multiplanar reconstructions allow assessment of relationship to ribs, clavicle, and scalene muscles

  • Gold standard for evaluation of thoracic outlet syndrome, atherosclerosis, and vascular trauma

MRI images

Subclavian artery MRI CORONAL IMAGE

CT images

subclavian artery anatomy CT coronal image -img-00000-00000

MRI image

subclavian artery anatomy MRI coronal image -img-00000-00000

CT image

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