Posterior Intercostal Artery Branches (Breast)

The posterior intercostal artery branches play a significant role in supplying blood to the lateral and deep aspects of the breast. These arteries originate from the descending thoracic aorta and travel between the ribs in the intercostal spaces, giving off lateral cutaneous branches that extend anteriorly to the breast tissue. They form part of the rich anastomotic network that ensures vascular redundancy in the mammary gland.

Structure

The posterior intercostal arteries are segmental branches of the thoracic aorta, usually arising from the third to the eleventh intercostal spaces. Each artery runs within the costal groove of the corresponding rib and gives off:

• Dorsal branches: Supply the vertebrae, spinal cord, and muscles of the back
• Lateral cutaneous branches: Pierce the intercostal muscles and continue toward the lateral breast and thoracic wall

The branches relevant to the breast are primarily the lateral cutaneous branches of the 2nd to 6th posterior intercostal arteries.

Location

These arteries originate from the posterior thoracic aorta and pass laterally and anteriorly in the intercostal spaces. The lateral cutaneous branches reach the subcutaneous tissue and skin of the lateral thorax and contribute to the vascular supply of the lateral breast.

Function

• Breast vascular supply: Lateral cutaneous branches provide arterial blood to the lateral and deep portions of the breast
• Thoracic wall support: Also supply intercostal muscles and overlying skin
• Anastomotic connections: These branches anastomose with anterior intercostal branches of the internal thoracic artery, forming a robust collateral circulation

Clinical Significance

• Breast surgery: Must be preserved or cauterized during lateral breast incisions (e.g., lumpectomy, mastectomy)
• Source of bleeding: Injury to lateral branches during trauma or invasive procedures may lead to hematoma
• Collateral flow: Important in cases of internal thoracic artery blockage or occlusion