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Incidence of the accessory internal thoracic artery and its safety area in the thoracic wall.

OBJECTIVE
To provide the incidence, origin, size and the safety area of the accessory internal thoracic artery (AITA) in the fourth intercostal space.


MATERIAL AND METHOD
One hundred and thirty two thoracic cages were dissected and examined for the presence of AITA. The origin, course, diameter and location in the fourth intercostal space of detected AITA were investigated.


RESULTS
AITA with diameter ranging from 0.6 to 3.05 (mean = 1.76 +/- 0.69) millimeters existed in 10 of 132 (7.58%) cadavers. They originated from the upper part of the internal thoracic artery, close and inferior to the subclavian artery (0-3 cm, mean = 2.4 +/- 0.78) and ran inferolaterally on the deep surface of the thoracic wall and ended in the second to the sixth intercostal spaces. Most of them ended in the fifth intercostal spaces (28.57%). The artery was present bilaterally in 4 cases (3.03%) and unilaterally in 6 cases (4.55%). Most of these arteries were located close to the midaxillary line (0-3 cm, mean = 1.73 +/- 1.18) in the fourth intercostal space which is endangered in several surgical procedures such as thoracoscopy.


CONCLUSION
Even the incidence of AITA is low (7.57%) but when present, it is endangered in thoracic surgical procedures. The safety area of AITA for surgical procedures in the fourth intercostal space is at least 3 centimeters anterior to the midaxillary line.