Dorsal branch of posterior intercostal artery

The dorsal branch of the posterior intercostal artery is a branch that arises from the vertebral segment (the most proximal portion) of the posterior intercostal artery, near the vertebral column. This branch courses posteriorly to supply the paraspinal muscles, vertebral structures, and overlying skin of the back.

The dorsal branches originate from the vertebral segment of the posterior intercostal artery, which is the portion closest to the aorta and vertebral bodies. These dorsal perforators are consistently present from the fourth to twelfth posterior intercostal arteries and are located within approximately 5 cm of the spinous processes of the vertebrae.

It gives three branches:

• Medial dorsal cutaneous branch of posterior intercostal artery

• Lateral dorsal cutaneous branch of posterior intercostal artery

• Spinal branch of posterior intercostal artery

The dorsal branches supply the erector spinae muscles, deep back muscles, and the skin overlying the paravertebral region. They also contribute to the vascular supply of the vertebral column and spinal cord. These vessels form anastomotic connections posterior to the laminae, creating a network that helps maintain blood supply to the paraspinal region.