Defects in the upper extremity may arise from trauma, but can also result from tumors and infections. The reconstruction of this region, characterized by its intricate network of nerves and blood vessels and the close interplay of bone, tendon, muscle, and skin, presents unique challenges due to its compact and complex structure. Optimal soft tissue reconstruction is crucial to protect the limb from contracture development, enable tendon and joint movements for functional preservation, and restore sensation. This chapter will focus on flaps, which are vital in the reconstruction of the upper extremity.