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Thoracoacromial artery

The thoracoacromial artery (also called the acromiothoracic artery) is a short but important branch of the second part of the axillary artery. It arises near the upper border of the pectoralis minor muscle, pierces the clavipectoral fascia, and quickly divides into four main branches: the pectoral, acromial, clavicular, and deltoid branches. These branches supply the pectoral muscles, clavicle, shoulder joint, deltoid, and acromion, as well as contribute to an extensive collateral network around the shoulder and thoracic wall.

Synonyms

  • Acromiothoracic artery

  • Thoracoacromial trunk

  • Truncus thoracoacromialis

Function

  • Supplies arterial blood to the pectoralis major and minor muscles

  • Provides vascular supply to the clavicle and acromion

  • Delivers blood to the deltoid muscle and shoulder joint

  • Contributes to the shoulder anastomotic network, ensuring collateral flow

Branches

  • Pectoral branch: largest, supplies pectoralis muscles and breast tissue

  • Acromial branch: supplies acromion and shoulder joint, anastomoses with suprascapular and posterior circumflex humeral arteries

  • Clavicular branch: supplies subclavius muscle and sternoclavicular joint

  • Deltoid branch: runs with cephalic vein in deltopectoral groove, supplies deltoid and pectoralis major

MRI Appearance

T1-weighted images:

  • Artery lumen appears as a signal void (black) due to blood flow

  • Vessel walls may be seen as thin hypointense rims within surrounding fat

  • Branches often inferred from their course along muscle planes

T2-weighted images:

  • Flow void persists; surrounding soft tissues and fat appear bright

  • Pathological conditions (aneurysm, thrombosis, or vascular malformations) may alter signal intensity

STIR (Short Tau Inversion Recovery):

  • Suppresses fat, enhancing visibility of vascular walls and adjacent pathology

  • Abnormal vessel wall changes (inflammation, edema) appear hyperintense

T1 Post-Contrast (Gadolinium-enhanced):

  • Thoracoacromial artery and its branches demonstrate intense homogeneous enhancement

  • Contrast improves visualization of small branches (pectoral, deltoid, acromial, clavicular)

  • Useful for evaluating stenosis, aneurysm, or tumor vascularity

CT Appearance

Non-contrast CT:

  • Artery appears as a soft tissue density structure in the fat plane between pectoralis and deltoid muscles

  • Not always well delineated without contrast

CT Angiography (CTA):

  • Clearly shows the origin from the axillary artery and its four branches

  • Contrast opacifies lumen, enabling detailed evaluation of anatomical variations, stenosis, aneurysm, or collateral circulation

  • Valuable for preoperative planning in chest wall, breast, or shoulder surgery

MRI image

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

CT imageS

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

CT imageS

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