Radial nerve arm, and later in the anterior compartment of the arm, and continues in the posterior compartment of the forearm. The radial nerve originates from the posterior cord of the brachial plexus with root values of C5 to C8 and T1. From the brachial plexus, it travels behind the third part of the axillary artery (part of the axillary artery distal to the pectoralis minor). In the arm, it runs behind the brachial artery and then enters the lower triangular space to reach the radial sulcus of back of the humerus. It travel downwards together with profunda brachii atery, between the
Perforating branches of internal thoracic artery Perforating branches of internal thoracic artery The perforating branches of the internal thoracic artery pierce through the internal intercostal muscles of the superior six intercostal spaces. These small arteries run with the anterior cutaneous branches of the intercostal nerves. The perforating arteries constitute part of the blood supply to the pectoralis major and the overlying tissue and skin. The second, third and fourth perforating branches give off medial mammary branches, which become enlarged during lactation. Chung, Kyung Wong, Ph.D. "Board Review Series: Gross Anatomy, 3rd ed. 114-115. Williams and Wilkins: 1995." Lockhart, R.D., et al. "Anatomy of the Human Body."