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Subscapular artery

The subscapular artery is the largest branch of the axillary artery, arising from its third part near the lower border of the subscapularis muscle. It courses along the posterior wall of the axilla, descending toward the inferior angle of the scapula. Shortly after its origin, it divides into two major terminal branches: the circumflex scapular artery and the thoracodorsal artery. Through these branches, the subscapular artery contributes to the scapular anastomosis, ensuring collateral circulation around the scapula, and supplies blood to the latissimus dorsi, subscapularis, teres major, and surrounding muscles.

Synonyms

  • Largest branch of axillary artery

  • Arteria subscapularis

  • Scapular branch of axillary artery

Function

  • Provides arterial supply to the subscapularis, latissimus dorsi, teres major, and serratus anterior muscles

  • Contributes to the scapular anastomosis, ensuring collateral blood flow between the subclavian and axillary arteries

  • Plays a role in maintaining vascular supply during upper limb movements or arterial obstruction

Branches

  • Circumflex scapular artery → passes through the triangular space, supplies the infraspinatus and posterior scapular region

  • Thoracodorsal artery → supplies the latissimus dorsi and serratus anterior, also gives small branches to intercostal spaces

MRI Appearance

T1-weighted images:

  • Appears as a signal void (black lumen) due to fast blood flow

  • Surrounded by fat planes in the axilla, which appear hyperintense, providing natural contrast

  • Walls may show intermediate signal if thickened or diseased

T2-weighted images:

  • Flowing blood remains a signal void, highlighting the vessel course

  • Pathology (e.g., aneurysm, thrombosis) appears as altered signal within the lumen

STIR (Short Tau Inversion Recovery):

  • Suppresses surrounding fat, improving visualization of the artery against adjacent soft tissues

  • Vessel lumen remains signal void, while perivascular edema or inflammation appears hyperintense

T1 Post-Contrast (MR Angiography):

  • Vessel lumen shows intense homogeneous enhancement

  • Clearly demonstrates the origin from the axillary artery, course, and bifurcation into thoracodorsal and circumflex scapular branches

  • Useful for detecting stenosis, aneurysm, or collateral pathways

CT Appearance

Non-contrast CT:

  • Subscapular artery appears as a small tubular soft tissue density structure in the axilla, not well distinguished without contrast

Contrast-enhanced CT (CT Angiography):

  • Vessel lumen fills with contrast, allowing excellent visualization of its origin, course, and branches

  • Clearly demonstrates scapular anastomosis and its contribution to collateral circulation

  • Best modality for evaluating trauma, aneurysm, occlusion, or surgical planning for flaps (e.g., latissimus dorsi flap in reconstructive surgery)

CT images

Subscapular artery anatomy CT axial image -img-00000-00000