11.1 Vascular Anatomy of the Upper Extremity

Knowledge of the vascular anatomy of the upper extremity is obviously crucial to the treatment of a wide variety of hand and upper limb conditions. This chapter is essentially organized from “top to bottom” in that we describe the anatomy sequentially throughout the upper limb. We highlight the anatomy of specific vessels important to the harvest of tissue transfers and show variations in the vascular anatomy of the upper limb. Additionally, we review the lymphatics and demonstrate anatomical applications of the anatomy.

11.2 Axillary Artery

The axillary artery provides the main vascular supply to the upper limb. It extends from the lateral border of the first rib to the inferior border of the teres major muscle. It is divided into three parts, based on its relationship to the pectoralis minor muscle (▶Table 11.1). ¹ In the first part of the axillary artery, one major branch, the superior thoracic artery, arises and supplies the first to third intercostal spaces and upper portion of the serratus anterior muscle and may send a branch to the pectoralis major muscle (▶Fig. 11.1).

The second part, posterior to the pectoralis minor muscle, provides two branches, the thoracoacromial and lateral thoracic arteries. The second part of the axillary artery is adjacent to the level of cords of the brachial plexus.

The thoracoacromial artery pierces the clavipectoral fascia and has four branches:

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  The clavicular branch supplies the subclavius and sends a nutrient branch to the clavicle.

  
  
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  The pectoral branches that course between pectoralis major and minor supply the muscles as well as the breast.

  
  
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  The deltoid branch runs through the deltopectoral groove, supplying the deltoid and pectoralis major. The deltoid branch gives off a cutaneous branch to supply the skin of the anterior aspect of the shoulder. Manchot referred to this artery as the “anterior subcutaneous deltoid artery.” ² There are usually three perforators to the skin over the anterior deltoid, with an average diameter of 0.8 mm. Most are musculocutaneous arteries with an average pedicle length of 37 ± 18 mm. ²

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  The Acromial branch supplies the medial border of the deltoid and reaches the acromion process, where it anastomoses with the suprascapular artery and forms the acromial network.

The lateral thoracic artery may arise from the second part of the axillary artery in about 50%, from a branch of the subscapular artery in 30%, from the first part of the axillary artery in 11%, or from the thoracoacromial artery in 7%. ³ It descends along the lateral border of the pectoralis minor and supplies the serratus anterior and pectoralis minor muscles; it also supplies branches to the lateral aspect of the breast and overlying skin.

Three major branches, the subscapular artery, anterior circumflex humeral artery, and posterior circumflex humeral artery, arise from the third part of the axillary artery. The subscapular artery is the largest branch of the axillary artery; it courses caudally along the border of the subscapularis, under the latissimus dorsi muscle. It is accompanied by the lower subscapular and thoracodorsal nerves and supplies the subscapularis, teres major, latissimus dorsi, and serratus anterior muscles as well as the axillary lymph nodes. The subscapular artery divides into two secondary branches, the circumflex scapular and the thoracodorsal arteries.

The circumflex scapular branch passes dorsally through the triangular space (borders: subscapularis, teres major, and long head of triceps) to reach the infraspinatus fossa, where it anastomoses with the suprascapular and dorsal scapular arteries.

The thoracodorsal branch is the continuation of the subscapular artery, which travels along the deep surface of the latissimus dorsi muscle. This artery is accompanied by the thoracodorsal nerve and supplies the latissimus dorsi and subscapularis muscles. Branches of this vessel supply the serratus anterior, intercostal muscles, and pectoral muscles (▶Fig. 11.2).

The anterior circumflex humeral artery may arise from a common stem with the posterior circumflex humeral artery. It runs deep to the coracobrachialis and the short and long heads of biceps, and it turns transversely around the anterior aspect of the surgical neck of the humerus. It anastomoses with the posterior circumflex humeral artery and branches of the thoracoacromial artery. The anterior circumflex humeral artery supplies small secondary branches: (1) the bicipital branch ascends the bicipital groove to enter and supply the tendon of the long head of the biceps, and (2) the pectoral branch descends along the tendon and supplies the pectoralis major muscle.

The posterior circumflex humeral artery passes dorsally through the quadrangular space (borders: teres minor, teres major, latissimus dorsi, and humerus) with the axillary nerve. It provides the primary vascular supply of the deltoid and teres major and minor muscles and gives off nutrient branches to the greater tubercle of the humerus, articular branches to the shoulder joint, acromial branches, and a descending muscular branch to the long and lateral heads of the triceps. The posterior circumflex humeral artery anastomoses with the ascending branch from the deep brachial artery. The deep brachial artery may arise from the posterior circumflex humeral artery in 7%, and the posterior circumflex artery is a branch of the deep brachial artery in 16%. ³

The posterior subcutaneous deltoid artery supplies the skin of the posterior aspect of the shoulder ^{2 , 4} and gives off two to three perforators which penetrate the marginal fibers of the deltoid muscle in 91%. The average diameter of the source vessel is 2.5 ± 0.3 mm, with an average pedicle length of 6 to 8 cm to the quadrangular space. ⁴ This vessel can provide the vascular supply of the “deltoid flap” (▶Fig. 11.3). ⁵

11.3 Brachial Artery

The brachial artery is the continuation of the axillary artery at the inferior border of the teres major muscle, and it ends in the antecubital fossa, where it divides into the radial and ulnar arteries. It lies medially in the neurovascular compartment of the arm, and as it courses distally, it gradually moves anterior to the humerus. At its termination, it lies midway between the two epicondyles of the humerus. ⁶ In the antecubital fossa, it lies medial to the bicipital tendon and passes deep to the bicipital aponeurosis. Throughout its course in the upper arm, the brachial artery is accompanied by the median nerve. The nerve crosses the artery and lies medial to it in the antecubital fossa. The artery is accompanied by one vein. ³ Bifurcation of the brachial artery around the antecubital fossa is considered an anatomical variation and may be present in around 5.75% of cases (▶Fig. 11.4). ⁷

In its course through the upper arm, the brachial artery sends an average of 6 cutaneous perforators (range, 2–10) which travel to the skin on either side of the biceps muscle. These arteries course between the biceps and the brachialis muscle to the skin over the lateral bicipital groove from the deltoid muscle insertion to the biceps tendon insertion. The vascular territory of the brachial artery is 162 ± 42 cm ² , the median diameter of the cutaneous perforators is 0.7 ± 0.4 mm, and the superficial length of individual perforators is 30 ± 14 mm. ⁴ The posterior brachial cutaneous artery is a large, consistent, cutaneous branch of the brachial artery which has a mean diameter of 1.5 mm and pedicle length of 6.2 cm. This artery supplies the posterior brachial arm flap, which could be harvested as a osteocutaneous flap with the lateral aspect of the distal part of the humerus. ^{4 , 8 , 9}

The branches of the brachial artery are (1) the profunda brachial artery, (2) the nutrient artery of the humerus, (3) the superior and inferior ulnar collateral arteries and the terminal branches, and (4) the radial and ulnar arteries.

The profunda brachial artery arises from the brachial artery posteromedially, just distal to the teres major muscle. In 55%, it arises as a single trunk; it may also arise as a common trunk with the superior ulnar collateral artery in 22%, from the axillary in 16%, or as a branch of the posterior circumflex humeral artery in 7%. ³ The artery courses laterally between the medial and lateral heads of the triceps, through the spiral groove together with the radial nerve, before piercing the lateral intermuscular septum. A deltoid branch arises and divides into two terminal branches, the middle and radial collateral arteries on either side of the intermuscular septum. It anastomoses with the descending branch of the posterior circumflex humeral artery that may arise from the profunda brachial artery in 16% (▶Fig. 11.5). ²

Some perforators of the profunda brachial artery follow the posterior antebrachial cutaneous nerve to the skin of the lateral aspect of the arm via direct branches distal to the deltoid muscle insertion. It contributes two to six perforators to a vascular territory of 131 ± 30 cm ² . ⁴

The middle collateral branch supplies the triceps entering through the medial head. It continues to the elbow, where it terminates at the olecranon articular network.

The radial collateral branch continues accompanying the radial nerve and supplies muscular branches to the lateral head of the triceps; it also supplies the skin over the lateral and distal half of the arm through septocutaneous perforators.

There are usually two perforators of the radial collateral branch which supply an average area of 64 ± 31 cm ² along the lateral aspect of the distal arm. The mean diameter of the perforators is 1.6 ± 0.2 mm with an average length of 5.8 cm. There is a musculocutaneous/septocutaneous perforator ratio of 3:2. ⁴ The posterior radial collateral artery supplies the lateral arm flap which can be harvested as an osteocutaneous free flap including the lateral aspect of the distal humerus ^{10 , 11} or as a distally based flap for elbow coverage based on the radial recurrent artery.

The profunda brachial artery descends between the brachioradialis and brachialis muscles to the region of the lateral epicondyle, where it anastomoses with the radial recurrent artery.

The nutrient humeral artery arises near the origin of the superior ulnar collateral artery, crosses the brachialis, and enters a foramen near or distal to the middle of the humerus.

The superior ulnar collateral artery arises from the ulnar side of the brachial artery at the level of the insertion of the coracobrachialis. In 22% of cases, it may have a common trunk with the profunda brachial. ³ This artery accompanies the ulnar nerve posterior to the medial epicondyle and anastomoses with the posterior ulnar recurrent artery.

In 30% of dissections, the superior ulnar collateral artery supplied the skin as a direct cutaneous branch from the brachial artery. In the remaining dissections, it supplied the skin through septocutaneous (95%) or musculocutaneous (5%) perforators. There are usually one to two perforators with a mean vascular territory of 94 ± 29 cm ² . The superficial pedicle length is 56 ± 34 mm and the diameter was 0.9 ± 2 mm. ⁴ The medial arm flap can be based on this vessel ^{12 , 13} ; however, the pedicle length is fairly short and the anatomy is quite variable.

The inferior ulnar collateral artery arises from the medial side of the brachial artery 5 cm proximal to the elbow and runs between the median nerve and the brachialis muscle and divides into anterior and posterior branches.

The inferior ulnar collateral artery and the ulnar recurrent artery together supply the medial aspect of the elbow, in an inverse relationship. An average of 2 ± 1 perforators were found in this territory, with a mean vessel diameter of 0.8 ± 0.2 mm, and a superficial length of 35 ± 12 mm. ⁴

A superficial brachial artery may arise from the axillary artery or from the proximal end of the brachial artery. This artery runs superficially in the arm, slightly more lateral than the brachial artery. When this artery is present, it divides into ulnar and radial arteries, and the usual brachial artery may be absent or provide deep brachial and common interosseous artery branches. When the ulnar artery arises from the superficial brachial, the first runs superficially to the forearm flexors.

A high origin of the radial artery occurs in 14.27% of cases, being the most frequent anatomical variation in 107 specimens in a series of 750 extremities, ⁷ and may be as proximal as the axillary artery or from the brachial artery. It usually lies medially and then anterior to the median nerve and medial to the biceps muscle, and runs in its usual position in the forearm. Uniting vessels that course deep to the biceps tendon were constant, as are referred to as a sling connection.

A high origin of the ulnar artery occurs in 2.26% of cases. ⁷ It may arise from the axillary or brachial arteries, usually lying anterior to the brachial and median nerves and superficial in the antecubital fossa. When derived from the axillary artery, it arises from its anterior aspect and courses between the lateral and medial cords of the median nerve.

A variant division of the brachial artery into ulnar and radial arteries as far as 8 cm distal to the antecubital fossa may lead to difficulties raising a standard radial forearm flap. ¹⁴

There are 15 cutaneous vascular territories in the upper arm, and each source artery provides a variable number of cutaneous perforators. An average of 48 ± 19 perforators (≥ 0.5-mm diameter) in 15 vascular territories supply the integument of the upper extremity. ⁴

11.4 Ulnar Artery

The ulnar artery is the larger of the two terminal branches of the brachial artery. It arises in the apex of the antecubital fossa. In the forearm, it runs deep to the pronator teres and flexor digitorum superficialis, to the ulnar side, where it continues deep to the flexor carpi ulnaris. It passes through the Guyon canal to the palm, where it divides into two branches and contributes to the superficial and deep palmar arterial arches (▶Fig. 11.6).

The ulnar artery consistently supplies the skin of the medial forearm. There are four to nine perforators; 69% of these arteries are musculocutaneous and penetrate the flexor carpi ulnaris muscle. The mean superficial length is 27 ± 14 mm. ⁴ An ulnar pedicled or free flap or a perforator-based flap may be harvested from this territory. ¹⁵

The ulnar nerve joins the artery at the distal end of the proximal third of the vessel and is located on its ulnar side. The artery is accompanied by two venae comitantes.

In the forearm, the ulnar artery gives rise to the ulnar recurrent, common interosseous, palmar carpal, and dorsal carpal arteries.

There are two ulnar recurrent branches, anterior and posterior. The anterior recurrent branch courses between the lateral edge of pronator teres and brachialis and supplies both muscles; it anastomoses anterior to the medial epicondyle with the inferior ulnar collateral artery. The posterior branch is larger than the anterior branch; it runs between the flexor digitorum superficialis and profundus and lies with the ulnar nerve between the two heads of the origin of the flexor carpi ulnaris. It supplies adjacent muscles, the elbow joint, and the ulnar nerve, and forms the cubital articular network anastomosing with the superior and inferior ulnar collateral, interosseous recurrent, and middle collateral arteries.

The common interosseous branch is a short trunk about 1.2-cm long that arises from the posterior aspect of the ulnar artery, about 2.5 cm from its origin; it passes dorsally and distally between the flexor digitorum profundus and flexor pollicis longus. It branches into anterior and posterior interosseous arteries.

The anterior interosseous branch runs distally along the anterior surface of the interosseous membrane. It supplies the flexor digitorum profundus and the flexor pollicis longus. It divides into two branches at the proximal border of the pronator quadratus, the anterior and posterior terminal branches. It is accompanied by a vena comitans and medially by the anterior interosseous branch of the median nerve (▶Fig. 11.7).

The skin territory for this anterior interosseous artery is over the distal dorsal forearm via its dorsal perforating branch. It has two to three perforators which emerge between the muscles of the first extensor compartment and the extensor digitorum communis tendons. The superficial length of the perforators is 21 ± 10 mm, with an average diameter of 0.5 ± 0.1 mm.

The median artery is a long thin vessel that arises from the anterior interosseous artery and runs distally between the flexor digitorum profundus and flexor pollicis longus to the median nerve and supplies it. In about 4 to 8% of cases, ^{3 , 7} the median artery is a large vessel that continues up to the hand, traversing the carpal ligament and participates in the formation of the superficial palmar arch. In 7 of 31 cases of a reported series, the median artery pierced the median nerve in the proximal third of the forearm. ⁷

A median artery that passes completely through the median nerve in the forearm may produce pronator syndrome; and when bilateral, the median artery may produce symptoms of carpal tunnel syndrome. ¹⁶

The anterior terminal branch passes between the pronator quadratus and the interosseous membrane and continues into the palmar carpal rete, where it anastomoses with the palmar carpal branches of the radial and ulnar arteries and the recurrent branch of the deep palmar arch.

The posterior terminal branch pierces the interosseous membrane and continues to the dorsum of the wrist, where it anastomoses to the dorsal carpal branch of the radial and ulnar arteries, in the dorsal carpal rete.

The posterior interosseous branch runs dorsally through the space formed by the interosseous membrane, oblique ligament, and ulna. It emerges between the abductor pollicis longus and supinator and continues distally between the deep and superficial extensors. An early branch is usually a recurrent interosseous artery that joins the arterial rete around the elbow; most of the remaining branches are muscular, supplying the superficial flexor muscles close to their origin from the medial epicondyle of the humerus. Most of the blood supply of the deeper muscles in the dorsum of the forearm is from the radial and radial recurrent arteries rather than from the posterior interosseous. The posterior interosseous nerve accompanies this artery. Near the wrist, this artery may anastomose with the anterior interosseous artery which is the basis of the pedicled posterior interosseous artery flap.

There are approximately three to five communicating vessels between the anterior and posterior interosseous arteries, traversing the interosseous membrane. ⁴ The posterior interosseous artery can give origin to a cutaneous flap from the posterior aspect of the forearm, based on the distal anastomosis of this artery with the anterior interosseous. ¹⁷ The skin of the posterior forearm is supplied by about five perforators of the posterior interosseous artery. ⁴ The posterior interosseous flap can be used as cutaneous and osteocutaneous flap. ^{18 , 19}

The palmar carpal branch is a branch of the posterior interosseous artery. It courses across the carpal ligaments in the floor of the carpal canal, where it anastomoses with other carpal arteries to form a palmar carpal arch.

The dorsal carpal branch runs around the ulna to anastomose at the dorsal carpal arch with the dorsal carpal branch of the radial artery and posterior terminal branch of the anterior interosseous artery. The ulnar artery lies radial to the ulnar nerve as it crosses the wrist. At the palm, the ulnar artery lies deep to the hypothenar fascia and divides into two branches, superficial and deep.

The superficial palmar arch courses between the palmar aponeurosis and the flexor tendons, approximately at the level of the ulnar end of the proximal palmar crease and a few millimeters distal to the flexor retinaculum. Within the central compartment of the hand, the arch lies anterior to the branches of the median nerve and gives off three common palmar digital arteries to the adjacent sides of the four fingers (▶Fig. 11.8a–d). These start superficial to the nerves but then run deep, running dorsally to the nerves in the fingers. This arch may be completed with the superficial palmar branch of the radial artery (30%) or by union with the deep palmar arch through the princeps pollicis artery (42%). ³ It branches in the common digital branch and palmar proper digital branches. It is well known that the vascular anatomy of the palmer arches show great variability and thus have been classified into two groups (▶Fig. 11.9). Group I, with the arch complete, was encountered in 78.5% of cases, ²⁰ with five subdivisions:

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  Type A: the classical arch formed by the superficial volar branch of the radial artery and the larger ulnar artery (34.5%).

  
  
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  Type B: formed entirely by the ulnar artery (37%).

  
  
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  Type C: ulnar artery and enlarged median artery (3.8%).

  
  
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  Type D: radiomediulnar intercommunications (1.2%).

  
  
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  Type E: well-formed arch initiated by the ulnar artery and completed by a large vessel derived from the deep arch (2%).

The volar interosseous artery was not noted to contribute to the arch formation, and no case of complete absence of the arch was found.

Group II is an incomplete arch, in which the contributing arteries do not anastomose or the ulnar artery does not reach the thumb and index finger. It was encountered in 21.5%, with patterns similar to those of group I, except for type E (▶Fig. 11.9).

Perforator arteries of this arch supply the skin over the palm and the ulnar three fingers, the ulnar half of the index finger, and the skin over the dorsum of the fingers. ⁴ When the superficial palmar arch is insufficient to supply a digital space, this territory is taken by palmar metacarpal arteries from the deep palmar arch.

The common digital arteries arise from the convexity of the superficial palmar arch (usually being three in number), join the three corresponding metacarpal arteries, and give rise to a pair of palmar proper digital arteries.

The palmar proper digital branches continue distally, on the adjacent sides of the ulnar four digits. A palmar proper digital artery arises independently from this arch and supplies the ulnar side of the little finger.

The palmar proper digital arteries lie between the palmar and dorsal digital nerves. These arteries anastomose on the proximal side of each interphalangeal joint; they supply the flexor tendons and the integument. A dorsal digital branch supplies the dorsum of the digits at the middle of the proximal phalanx, and a second smaller branch supplies the distal phalanx.

The deep branch of the ulnar artery enters the hypothenar musculature between the abductor digiti minimi and flexor digit minimi brevis and supplies the hypothenar muscles. It anastomoses with the radial artery to form the deep palmar arch.

A superficial ulnar artery may be present in 0.7 to 9.4% of the population. ²¹ This superficial course occurs in almost every case in which the ulnar artery has a high origin. When this artery is present, the interosseous artery arises from the radial artery. ³