(2.35)
We'll move on now, to look at the arteries. In the dissections that follow, all the accompanying veins have been removed, to simplify the picture.
To get a good look at the artery as it runs from here, to here, we need to remove pectoralis major. Now only three structures stand between us and it. Here's the artery, passing behind the anterior scalene muscle, behind the clavicle, and behind pectoralis minor. Three names for one artery: subclavian, axillary, brachial. Let's see where it begins.
Here's a deeper dissection with the chest wall removed. Here are the divided ends of the clavicle, the first rib, the anterior scalene muscle, and the second rib. In the middle we're looking at the trachea, and the common carotid arteries, the right, and the left. On the right side, the subclavan artery arises, along with the common carotid, from the brachiocephalic trunk, which in turn arises from the arch of the aorta. On the left side, the subclavian artery arises directly from the arch of the aorta.
Here's a deeper dissection with the chest wall removed. Here are the divided ends of the clavicle, the first rib, the anterior scalene muscle, and the second rib. In the middle we're looking at the trachea, and the common carotid arteries, the right, and the left. On the right side, the subclavan artery arises, along with the common carotid, from the brachiocephalic trunk, which in turn arises from the arch of the aorta. On the left side, the subclavian artery arises directly from the arch of the aorta.
The main artery, now called the axillary, next gives off two branches behind pectoralis minor. They're the thoraco-acromial, and the lateral thoracic arteries. In the axilla, three more branches arise, often close together: the subscapular, and the two circumflex humeral arteries, the anterior and the posterior. The posterior circumflex humeral winds round behind the neck of the humerus. Finally the artery, now known as the brachial artery, passes on down the upper arm.