Brachial fascia Brachial fascia The brachial fascia (deep fascia of the arm) is continuous with that covering the deltoideus and the pectoralis major muscle, by means of which it is attached, above, to the clavicle, acromion, and spine of the scapula; it forms a thin, loose, membranous sheath for the muscles of the arm, and sends septa between them; it is composed of fibers disposed in a circular or spiral direction, and connected together by vertical and oblique fibers. It differs in thickness at different parts, being thin over the biceps brachii, but thicker where it covers the triceps brachii, and over
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."