What artery primarily supplies blood to a radial flap?

The radial flap is primarily supplied by the radial artery, which is the correct answer. The radial artery runs along the radial side of the forearm and supplies blood to various structures, including the hand. In the context of a radial flap, which is often used in reconstructive surgery of the hand and forearm, the vascularized tissue includes skin and other structures that receive their blood supply from this artery.

The importance of the radial artery lies in its consistent anatomic location and sufficient caliber, making it an ideal donor vessel for flaps. Additionally, the radial artery has reliable perforators that can be anastomosed to ensure adequate blood supply to the flap once it is transferred to the recipient site.

In contrast, while the ulnar artery does supply some areas of the forearm and hand, it does not provide the primary blood supply to a radial flap. The brachial artery mainly supplies the upper arm and also gives off branches, but it is not directly involved in the blood supply of a radial flap. The axillary artery is responsible for supplying the shoulder and upper limb before it branches into the brachial artery, making it even less relevant to the vascularization of a radial flap.