The arterial circulation of the upper limb is depicted in Fig. 7.1. The subclavian arteries are the major arteries supplying the upper limbs. On the right side the subclavian artery is one of the terminal branches of the brachiocephalic trunk , while on the left it is one of the direct branches of the aortic arch. The subclavian artery passes immediately superior to the first rib and becomes the axillary artery at the lateral margin of this rib. The axillary artery , in turn, becomes the brachial artery as it reaches the inferolateral aspect of the teres major muscle. Although the brachial artery occasionally ends in its terminal division in the proximal arm, it usually continues to reach the neck of the radius, where it bifurcates into the radial and ulnar arteries just medial to the tendon of the biceps brachii muscle. The radial and ulnar arteries continue into the hand, ending as the deep and superficial palmar arterial arches, respectively (see Fig. 7.1).

Venous drainage occurs via both deep and superficial veins . The deep veins follow the course of the arteries. In the distal limb, paired veins are intimately associated with the arteries as venae comitantes. These veins are encased in the perivascular connective tissue sheath that surrounds both the artery and these deep veins. More proximally, the venae comitantes join to form a single deep vein paralleling the artery. The superficial veins (depicted in Fig. 7.2) include the cephalic (lateral) and basilic (medial). The superficial veins are connected to the deep system via venous connections with valves that limit retrograde flow from the deep to superficial systems. We will first discuss the arterial system before considering the veins.

In addition to being the principal artery of the upper limb, the subclavian artery supplies many structures in the neck, the scapular region, and pectoral region, with branches reaching as far distally as the upper abdominal wall . The left subclavian artery is normally somewhat longer, arising directly from the aortic arch. This is distinct from the right subclavian, which is a terminal branch of the brachiocephalic trunk . Occasionally, the right subclavian artery takes origin directly from the aorta, in which case it passes posterior to the esophagus.

The subclavian artery has three portions (Fig. 7.3) with the first part extending from the artery’s origin to the medial border of the anterior scalene muscle, which is directly anterior to the artery. This portion is somewhat longer on the left side since the left subclavian has a significant intrathoracic portion prior to reaching the anterior scalene muscle. On both sides, the first part of the subclavian is just posterior to the sternoclavicular joint and several muscles (the sternocleidomastoid, sternohyoid, and sternothyroid). It is also posterior to several vascular structures (including the internal jugular vein and, on the left, the thoracic duct) and neural structures (the phrenic nerve on the left side, the vagus nerve, parasympathetic and sympathetic cardiac nerves, and the ansa subclavia of the sympathetic chain, which encircles the subclavian artery). This first part of the subclavian artery is just anterior to the apex of the lung (and the associated pleural cupola and suprapleural membrane) and several neural structures (including the sympathetic trunk and inferior cervical ganglion as well as the right recurrent laryngeal nerve).

The second portion of the subclavian artery is quite short and it arches above the clavicle. This portion of the artery is immediately posterior to the anterior scalene muscle, which separates the artery from the sternocleidomastoid, right phrenic nerve, and subclavian vein. It is immediately anterior to the middle scalene muscle as well as the apex of the lung and associated membranes.

The third part of the subclavian artery can be palpated within the supraclavicular triangle at the base of the neck, where it is immediately superior to the first rib. In this location it is posterior to the external jugular vein, the clavicle, and the subclavian vein. It is anterior to the lower trunk of the brachial plexus and middle scalene muscle.

The majority of the branches of the subclavian artery arise from the first part of the artery medial to the anterior scalene. The exceptions include the right costocervical trunk, which usually arises from the second part, and the dorsal scapular artery (when present), which usually arises from the third part. The first three branches of the subclavian artery are the vertebral and internal thoracic arteries and the thyrocervical trunk .

The vertebral artery arises from the first part of the subclavian artery, although the left vertebral artery may branch from the aortic arch or the brachiocephalic trunk on rare occasions. This artery traverses the transverse foramina of the upper six cervical vertebrae, where it then turns to pass medially along the posterior arch of the atlas. It then penetrates the posterior atlanto-occipital membrane and passes though the foramen magnum. It joins with its mate of the other side to become the basilar artery forming the posterior circulation of the brain. The first part of the vertebral artery, the cervical part, passes posterior to the common carotid artery. The inferior thyroid artery crosses anterior to the vertebral artery, as does the thoracic duct on the left. The inferior cervical sympathetic ganglion is immediately anterior to the vertebral artery, as are the C7 and C8 roots of the brachial plexus. The cervical part of the vertebral artery gives muscular branches to the deep muscles of the neck.

The second part of the vertebral artery, the vertebral part, typically ascends through the transverse foramina from C6 to the atlas, although it rarely begins at C7 or C5. It is accompanied by a venous plexus and by sympathetic nerve fibers . Branches include variable spinal branches that include some radicular arteries that follow nerve roots to the spinal cord.

The internal thoracic (aka, internal mammary) artery is the second branch of the subclavian artery. This artery passes posterior to the subclavian and internal jugular veins and anterior to the cupola of the lung. The phrenic nerve crosses it obliquely, where the nerve can be damaged by procedures that use the internal thoracic artery for coronary bypass grafting. The internal thoracic artery passes posterior to the upper six costal cartilages immediately lateral to the sternum where it is held in place by the endothoracic fascia and slips of the transverse thoracic muscle intervene. Upon reaching the costal margin, the internal thoracic artery divides to become the superior epigastric and musculophrenic arteries .

The thyrocervical trunk (Fig. 7.3) divides into three branches almost immediately after arising from the first part of the subclavian artery. These are the inferior thyroid, transverse cervical, and suprascapular arteries.

The inferior thyroid artery (Fig. 7.1), which is occasionally absent, passes superior, immediately anterior to the anterior scalene muscle. It then arches medially to pass anterior to the vertebral vessels and posterior to the carotid sheath . In this location it is in very close proximity to the sympathetic chain, usually adjacent to the middle cervical sympathetic ganglion at the C6 vertebral level. The inferior thyroid artery passes anterior to the anterior scalene and longus coli muscles and to the vertebral artery. The inferior thyroid artery may pass posterior or anterior to the recurrent laryngeal nerve. This artery penetrates the fibrous capsule at the lower pole of the thyroid gland , dividing into several branches usually near the inferior parathyroid glands. These glandular branches anastomose with superior laryngeal artery branches and with its mate from the opposite side. In its course the inferior thyroid artery usually gives rise to visceral branches and a recurrent laryngeal branch that follows the nerve of the same name.

The suprascapular (or transverse scapular) artery (Fig. 7.1) is another branch of the thyrocervical trunk. It passes laterally, anterior to the anterior scalene and the phrenic nerve. Beyond the lateral border of the anterior scalene muscle it is anterior to the subclavian artery and the cords of the brachial plexus. More laterally it is posterior to the clavicle and subclavius muscle. It then passes superior to the transverse scapular ligament to reach the posterior aspect of the scapula. The suprascapular artery has muscular branches in the supraspinous fossa and then passes lateral to the root of the spine of the scapula to enter the infraspinous fossa, where it ramifies widely, including muscular branches. Its branches anastomose with branches of other arteries including the dorsal scapular and subscapular to form an anastomosis around the scapula. Occasionally the suprascapular artery arises from the third part of the subclavian artery and very rarely from other arteries, including the axillary artery.

The transverse cervical artery usually is a branch of the thyrocervical trunk , often arising as a common stem with the suprascapular artery. It is somewhat superior to but otherwise parallels the suprascapular artery, crossing the anterior scalene muscle and phrenic nerve. It generally passes deep to the trapezius muscle as it exits the posterior aspect of the posterior triangle of the neck. Alternatively, it may divide into a superficial branch and a deep branch that pass on either side of the levator scapulae muscle. In this arrangement, the deep branch takes the place of the dorsal scapular artery (see below).

The ascending cervical artery may arise either directly from the thyrocervical trunk or from the transverse cervical artery. It ascends the cervical spine in close proximity to the lateral aspect of the spine and the longus colli muscles. It supplies deep paraspinal muscles and contributes to an arterial plexus in the spinal canal with some branches following nerve roots to the spinal cord.