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6. Arteries of upper extremity course, syntopy, branches.
Axillary Artery
From: Subclavian art.
To: Brachial art.
This is the continuation of the subclavian artery. It commences at the lateral border
of the 1st rib and ends at the inferior border of teres major to become the brachial
artery. It is divided into three parts by pectoralis minor. It is invested in a fascia1
sheath arising from the prevertebral fascia.
First part is medial to the upper border of pectoralis minor and has one branch.
Anterior to it is the clavipectoral fascia, subclavius and the lateral pectoral nerve.
The axillary vein is medial whilst posterior to it are the upper part of serratus anterior,
the long thoracic nerve, the medial pectoral nerve and the medial cord of the
brachial plexus. Lateral to it are the lateral and posterior cords of the brachial plexus.
Second part has pectoralis minor lying anterior to it and has two branches. Medial
to it is the axillary vein and medial cord of the brachial plexus. Posterior to it are the
posterior cord and subscapularis whilst lateral to it is the lateral cord of the brachial
plexus.
Third part extends from the lower border of pectoralis minor to the inferior border of
teres major and has three branches. Anterior to it are pectoralis major, the
clavipectoral fascia and the median nerve. Medial to it lie the axillary vein and the
ulnar nerve. Posterior to it are the radial nerve, teres major, subscapularis and the
tendon of latissimus dorsi. On its lateral side lie the musculocutaneous nerve, lateral
root (head) of the median nerve, the tendon of biceps in the bicipital groove and
coracobrachialis.
Posterior circumflex humeral artery. Passes posteriorly through the quadrangular
space with the axillary nerve to supply shoulder joint and surrounding muscles.
Note. Lateral thoracic artery and pectoral branches of the thoraco-acromial trunk are
important supply vessels for the breast.
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Brachial artery
From: Axillary art.
To: Radial & ulnar arts.
This is the continuation of the axillary artery beginning at the lower margin of the
teres major and ending in the cubital fossa at the level of the neck of the radius as
the radial and ulnar arteries. At first it lies medial to the humerus then it spirals
around to lie anterior to it. It is superficial throughout its course and accompanied by
venae commitantes. It is crossed from lateral to medial by the median nerve in the
mid arm and by the bicipital aponeurosis in the cubital fossa. Medial to it is the ulnar
nerve in the upper arm and, distally, the median nerve. Lateral to it high up are the
median and musculocutaneous nerves. Coracobrachialis, biceps and its tendon also
lie on its lateral side. The artery lies first on the long and then the medial head of
triceps, then brachialis in the lower third of the arm.
Arteria profunda brachii. Leaves the posteromedial aspect of the brachial artery
just below teres major and passes posteriorly between the long and medial heads of
triceps with the radial nerve and into the radial groove before breaking up into its
terminal branches.
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Radial artery
From: Brachial art in midline of cubital fossa.
To: Deep palmar arch in hand.
The radial artery arises at the terminal bifurcation of the brachial artery in the cubital
fossa at the level of the neck of the radius. It crosses anterior to the biceps tendon to lie
initially on supinator. It then passes down the radial side of the forearm lying
consecutively on pronator teres, the radial head of flexor digitorum superficialis, flexor
pollicis longus and the insertion of pronator quadratus before passing onto the lower
end of the radius where its pulse is palpable as it lies lateral to the tendon of flexor carpi
radialis. It thus lies deep to brachioradialis and, to a lesser extent, flexor carpi radialis.
The superficial branch of the radial nerve lies lateral to it in the forearm. It gives off a
palmar carpal branch which contributes to the palmar carpal arch. It then gives off a
superficial palmar branch (palmar cutaneous branch) which supplies the thenar muscles
before anastomosing with the superficial palmar arch. The radial artery then passes
beneath the tendons of abductor pollicis longus and extensor pollicis brevis to enter the
anatomical snuff box. It passes across the snuff box on the scaphoid and trapezium and
under the tendon of extensor pollicis longus. It gives off a dorsal carpal branch to the
dorsal carpal arch which in turn supplies the wrist joint, the dorsal aspects of the
metacarpals and the dorsal digital arteries. The radial artery then gives off two named
vessels-arteria radialis indicis and princeps pollicis (first palmar metacarpal artery). It
next passes down between the two heads of the first dorsal interosseous then between
the two heads of adductor pollicis to enter the palm of the hand and form the deep
palmar arch. The deep palmar arch lies 1 cm proximal to the superficial palmar arch
(ulnar artery). It supplies the palmar metacarpals, gives off a recurrent branch to the
palmar carpal arch and three perforating branches which anastomose with the dorsal
metacarpa arteries.
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Ulnar artery
From: Brachial art.
To: Superficial palmar arch in hand.
The artery arises as the terminal bifurcation of the brachial artery in the cubital fossa
at the level of the neck of the radius. It leaves the fossa deep to the deep head of
pronator teres and deep to the fibrous arch of flexor digitorum superficialis just
lateral to the median nerve to cross beneath the nerve before running down the
ulnar side of the forearm. It lies on flexor digitorum profundus with the ulnar nerve on
its medial side. It lies lateral to flexor carpi ulnaris before passing superficial to the
flexor retinaculum. The dorsal and palmar carpal arteries contribute, with similarly
named arteries from the radial artery, to the dorsal and palmar carpal arches. The
ulnar artery then gives off a deep branch to the deep palmar arch before forming the
superficial palmar arch at the level of the distal border of the extended thumb. The
superficial arch supplies the hypothenar eminence and gives off the palmar digital
arteries. At the level of pronator teres the ulnar artery gives off the common
interosseous artery which divides into anterior and posterior interosseous arteries.
Anterior interosseous artery. Descends on the anterior surface of the interosseous
membrane together with the anterior interosseous branch of the median nerve lying
between flexor digitorum profundus medially and flexor pollicis longus laterally.
Branches perforate the membrane to supply the extensor muscles. Above pronator
quadratus it gives off a small branch which descends deep to the muscle to join the
palmar carpal arch, then the anterior interosseous artery itself passes posteriorly
through the membrane to anastomose with the posterior interosseous artery which
descends to join the dorsal carpal arch.
Posterior interosseous artery. Passes posteriorly above the interosseous
membrane and then runs between supinator superficially and abductor pollicis
longus deeply with the deep branch of the radial nerve (posterior interosseous
nerve) to descend to supply the extensor muscles of the forearm. It anastomoses
with the distal branches of the anterior interosseous artery and dorsal carpal arch.
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