The branch for the second intercostal space usually joins with one from the highest aortic intercostal artery. This branch of the subclavian artery originates from the first part, and it is composed of four parts – cervical, vertebral, suboccipital and cranial. LIST OF ILLUSTRATIONS The subclavian arteries are a pair of large arteries in the thorax that supply blood to the thorax itself, head, neck, shoulder and arms. 1.
The first portions of the two vessels require separate descriptions; the second and third parts of the two arteries are practically alike. Cervical: It arises from the first part of the subclavian artery and ascends in the pyramidal space formed between the scalene and longus muscles. Each intercostal gives off a posterior branch which goes to the posterior vertebral muscles, and sends a small spinal branch through the corresponding intervertebral foramen to the medulla spinalis and its membranes. I. Embryology As the subclavian artery crosses the lateral border of the first rib, it becomes the axillary artery. The left subclavian is occasionally joined at its origin with the left carotid. IV. Syndesmology
—The first part of the right subclavian artery arises from the innominate artery, behind the upper part of the right sternoclavicular articulation, and passes upward and lateralward to the medial margin of the Scalenus anterior. In the first intercostal space, it gives off a branch which is distributed in a manner similar to the distribution of the aortic intercostals.
Surface Anatomy and Surface Markings The artery may ascend as high as 4 cm. 2. Occasionally, it perforates the Scalenus anterior; more rarely it passes in front of that muscle. VII. above the clavicle, or any intermediate point between this and the upper border of the bone, the right subclavian usually ascending higher than the left. Myology This branch is not constant, but is more commonly found on the right side; when absent, its place is supplied by an intercostal branch from the aorta. X. Each artery subclavian artery can be divided into three sections: the first, second, and third parts. The origin of the right subclavian from the innominate takes place, in some cases, above the sternoclavicular articulation, and occasionally, but less frequently, below that joint. III. The first portion extends from the origin of the vessel to the medial border of the Scalenus anterior; the second lies behind this muscle; and the third extends from the lateral margin of the muscle to the outer border of the first rib, where it becomes the axillary artery.
First part– it extends from the origin to medial border of scalenus anterior. The Arteries IX. The first part extends from the origin up to the muscle. The posterior border of the Sternocleidomastoideus corresponds pretty closely to the lateral border of the Scalenus anterior, so that the third portion of the artery, the part most accessible for operation, lies immediately lateral to the posterior border of the Sternocleidomastoideus. From its origin, the subclavian artery travels laterally, passing between anterior and middle scalene muscles, with the anterior scalene (scalenus anterior) on its anterior side and the middle scalene (scalenus medius) on its posterior. Osteology The Organs of the Senses and the Common Integument SUBJECT INDEX, X. This is in contrast to the subclavian vein, which travels anterior to the scalenus anterior.
Depending on the side of the body, it can have two origins: the aortic arch on the left and the brachiocephalic trunk on the right. When it is the first branch, it occupies the ordinary position of the innominate artery; when the second or third, it gains its usual position by passing behind the right carotid; and when the last branch, it arises from the left extremity of the arch, and passes obliquely toward the right side, usually behind the trachea, esophagus, and right carotid, sometimes between the esophagus and trachea, to the upper border of the first rib, whence it follows its ordinary course. The chief agent in the restoration of the axillary artery below the tumor was the subscapular artery, which communicated most freely with the internal mammary, transverse scapular and descending ramus of the transverse cervical branches of the subclavian, from all of which it received so great an influx of blood as to dilate it to three times its natural size. The subclavian artery becomes the axillary artery in the end, the arterial supply to the upper limb, regardless of which side of the body it is.
First Part of the Right Subclavian Artery (Figs.