A cardiac surgeon plans a left internal mammary artery graft to the anterior interventricular artery. From which part of its parent vessel does the left internal thoracic artery arise?
- A Second part of the subclavian artery
- B First part of the subclavian artery ✓
- C Third part of the subclavian artery
- D Arch of the aorta, distal to the left subclavian origin
Correct answer: B. First part of the subclavian artery
Explanation
The subclavian artery is divided into three parts by the scalenus anterior muscle. The first part, medial to the muscle, gives three branches: the vertebral artery, the internal thoracic (internal mammary) artery and the thyrocervical trunk. The second part gives only the costocervical trunk, while the third part gives the dorsal scapular artery when it arises independently. Its long vertical descent beside the sternum makes the LIMA an ideal conduit for the LAD.
Reference: Gray's Anatomy for Students, 4th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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