In adults, the internal thoracic artery lies closest to the sternum at the first intercoastal space. The gap between the artery and lateral border of the sternum increases when going downwards, up to 1.1 cm to 1.3 cm at the sixth intercoastal space. In children, the gap ranges from 0.5 cm to 1.0 cm.[5]
Twelve
anterior intercostal branches, two to each of the top six
intercostal spaces. In a given space, the upper branch travels laterally along the bottom of the rib until it
anastomoses with its corresponding posterior intercostal artery. The lower branch of the space anastomoses with a collateral branch of the posterior intercostal artery.
After passing the sixth intercostal space, the internal thoracic artery splits into the following two terminal branches:
Musculophrenic artery - roughly follows the costal margin and it again gives branch for 7,8,9 ribs
Superior epigastric artery - continues the course of the internal thoracic artery, travelling downward into the abdominal wall and to the content of rectus sheath
Function
The internal thoracic artery supplies the chest wall and the breasts.[1]
Plastic surgeons may use either the left or right internal thoracic arteries for autologous
free flap reconstruction of the breast after
mastectomy. Usually, a microvascular
anastomosis is performed at the second intercostal space to the artery on which the free flap is based.
^Jelicić N, Djordjević L, Stosić T (1996). "Unutrasnji grudni krvni sudovi (a. et vv. thoracicae internae) i njihov prakticni znacaj" [The internal thoracic blood vessels (internal thoracic arteries and veins) and their practical significance]. Srpski Arhiv Za Celokupno Lekarstvo (in Serbian). 124 (3–4): 58–61.
PMID9102819.
^Kitamura, S; Kawachi, K; Kawata, T; Kobayashi, S; Mizuguchi, K; Kameda, Y; Nishioka, H; Hamada, Y; Yoshida, Y (1996). "Ten-year survival and cardiac event-free rates in Japanese patients with the left anterior descending artery revascularized with internal thoracic artery or saphenous vein graft: a comparative study". Nippon Geka Gakkai Zasshi. 97 (3): 202–9.
PMID8649330.