This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood Vessels of Thorax, Subject name: Anatomy
True about internal thoracic artery is- 
Select and explain. 
A. Arises from 1st part of subclavian artery, B. Pericardiophrenic is a terminal branch, C. Divides in the 4th intercostal space, D. Descends at posterior end of intercostal space
A: Arises from 1st part of subclavian artery
Answer: A: Arises from 1st part of subclavian artery 
Explanation: Ans. is 'a'i.e., Arises from 1st part of subclavion artery Internal thoracic arteryo It arises from 1st part of subclavian artery and descends through anterior ends of upper six intercostal spaces lying 1[?]25 cm lateral to sternal margin.o It divides into two terminal branches, musculophrenic and superior epigastric in 6th intercostal spaceo Branches of internal thoracic artery are:-i) Mediastinal branchesii) Pericardial branchesiii) Sternal branchesiv) Pericardiophrenic branchesv) Anterior intercostal arteries (in upper six spaces)vi) Perforating branchesvii) Two terminal branches, musculophrenic and superior epigastric.