Arteries of the upper limbs

# The Axillary Artery
- The axillary artery is divided into 3 parts for description.
- The first part is between the lateral border of the first rib and the superior border of the pectoralis minor muscle.
- The second part lies deep to the pectoralis minor muscle.
- The third part extends from the inferior border of the pectoralis minor muscle to the inferior border of the teres major muscle.

## First Part of the Axillary Artery
- This part is enclosed in the axillary sheath along with the axillary vein.
- This part of the axillary artery has only one branch, the supreme thoracic artery.
- This artery helps to supply the first two intercostal spaces and the superior part of the serratus anterior muscle.

## Second Part of the Axillary Artery
- This part of the artery lies deep to the pectoralis minor muscle.
- The lateral, medial and posterior cords of the brachial plexus are so named respective to this part of the axillary artery.
- This part of the axillary artery has two branches, the thoracoacromial and lateral thoracic arteries.

### The Thoracoacromial Artery
- This is a short, wide trunk that arises from the axillary artery deep to the pectoralis minor muscle.
- It pierces the costocoracoid membrane, which is part of the clavipectoral fascia.
- It then divides into 4 branches (acromial, deltoid, pectoral, and clavicular) deep to the clavicular head of the pectoralis major muscle.

### The Lateral Thoracic Artery
- This nerve descends along the axillary border of the pectoralis minor muscle.
- It supplies the pectoral muscles and the axillary lymph nodes.
- The lateral thoracic artery is large in women, and is an important source of blood to the lower part of the mammary glands.

## Third Part of the Axillary Artery
- This part extends from the inferior border of the pectoralis minor muscle to the inferior border of the teres major muscle.
- It has three branches, the anterior and posterior circumflex humeral arteries and the subscapular artery.

# The Circumflex Humeral Arteries
- These arteries pass around the surgical neck of the humerus and anastomose with each other.
- The anterior circumflex humeral artery passes laterally, deep to the coracobrachialis and the biceps brachii muscles.
- It gives off an ascending branch that supplies the shoulder, but the main artery winds around the surgical neck of the humerus.
- The larger posterior circumflex humeral artery passes through the posterior wall of the axilla through the quadrangular space.
- It is accompanied by the axillary nerve to supply the surrounding muscles.

# The Subscapular Artery
- This is the largest branch of the axillary artery.
- It descends along the lateral border of the subscapularis muscle and divides into the circumflex scapular artery and the thoracodorsal artery.
- The circumflex scapular artery passes around the lateral border of the scapula to supply muscles on the dorsum of the scapula.
- The thoracodorsal artery continues the general course of the subscapular artery to supply adjacent muscles, principally, the latissimus dorsi muscle.

# The Brachial Artery
- This artery begins at the inferior border of the teres major muscle as the continuation of the axillary artery.
- It runs inferiorly and slightly laterally on the medial side of the biceps brachii muscle to the cubital fossa, where it ends opposite the neck of the radius.
- It is superficial and palpable throughout its whole length.
- At first it lies medial to the humerus and then anterior to it.
- It lies anterior to the triceps brachii and brachialis muscles, and is overlapped by the biceps brachii and coracobrachialis muscles.
- It accompanies the median nerve, which crosses it anteriorly at the middle of the arm.
- Under the cover of the bicipital aponeurosis, the brachial artery divides into the radial and ulnar arteries.
- The brachial artery gives rise to many unnamed muscular branches, mainly from its lateral side.
- The named branches of the brachial artery are the profunda brachii artery, the nutrient humeral artery, and the ulnar collateral arteries (superior and inferior).

## The Profunda Brachii Artery
- This is the largest branch of the brachial artery, and has the most superior origin.
- It accompanies the radial nerve in its posterior course in the radial groove.
- Posterior to the humerus, the profunda brachii artery (or deep brachial artery) divides into anterior and posterior ascending branches.
- These help form the arterial anastomoses of the elbow region.

## The Superior Ulnar Collateral Artery
- This arises from the brachial artery near the middle of the arm.
- It accompanies the ulnar nerve posterior to the medial epicondyle of the humerus.
- Here, it anastomoses with the posterior ulnar recurrent branch of the ulnar artery and the inferior ulnar collateral artery.

## The Inferior Ulnar Collateral Artery
- This arises from the brachial artery about 5 cm proximal to the elbow crease.
- It then passes inferomedially, anterior to the medial epicondyle of the humerus.
- Here, it joins the anastomoses of the elbow region.

# The Radial Artery
- It begins in the cubital fossa, opposite the neck of the radius.
- The proximal part of the radial artery is overlapped by the fleshy belly of the brachioradialis muscle.
- The radial artery lies on muscle until it comes into contact with the distal end of the radius, where it is covered only by superficial and deep fascia and skin.
- It leaves the forearm by winding around the lateral aspect of the radius.
- It passes posteriorly between the lateral collateral ligament of the wrist joint and the tendons of the abductor pollicis longus and extensor pollicis brevis muscles.
- The radial artery crosses the floor of the anatomical snuffbox formed by the scaphoid and trapezium bones.
- It enters the palm of the hand by passing between the heads of the first dorsal interosseous muscle.
- The radial artery gives off the princeps pollicis artery and the radialis indicis artery (arteries to the thumb and index fingers).
- The radial artery then passes between the two heads of adductor pollicis muscle and ends by completing the deep palmar arterial arch in conjunction with the ulnar artery.

## Branches of the Radial Artery
- Muscular branches of the radial artery supply muscles on the lateral side of the forearm.

### The Radial Recurrent Artery
- This arises from the lateral side of the radial artery, just distal to its origin.
- It ascends between the brachioradialis and the brachialis muscles.
- It supplies these muscles, the elbow joint, and anastomoses with the radial collateral artery, a branch of the profunda brachii artery.

### The Superficial Palmar Branch
- This arises at the distal end of the radius, just proximal to the wrist.
- It passes through and sometime over the muscles of the thenar eminence, which it supplies.
- It usually anastomoses with the terminal part of the ulnar artery to form a superficial palmar arterial arch.

### The Dorsal Carpal Branch
- This runs medially across the dorsal surface of the wrist, deep to the extensor tendons.
- Here it anastomoses with the dorsal carpal branch of the ulnar artery and with the terminations of the anterior and posterior interosseous arteries to form the dorsal carpal arch.

### Palmar Metacarpal Arteries
- There are three of these arteries and they arise from the deep palmar arch and run distally, where they joint the common palmar digital arteries, which arise from the superficial palmar arterial arch.

# The Ulnar Artery
- This artery begins near the neck of the radius, just medial to the biceps brachii tendon.
- It is the larger of the two terminal branches of the brachial artery.
- The ulnar artery passes inferomedially deep to the pronator teres muscle.
- With the median nerve, the ulnar artery passes between the ulnar and radial heads of the flexor digitorum superficialis muscle.
- About midway between the elbow and the wrist, the ulnar artery crosses posterior to the median nerve to reach the medial side of the forearm, where it lies on the flexor digitorum superficialis muscle.
- In the distal 2/3 of the forearm, the ulnar artery lies lateral to the ulnar nerve.
- It leaves the forearm by passing superficial to the flexor retinaculum on the lateral side of the pisiform bone.
- At the wrist, the ulnar artery and nerve lie lateral to the tendon of flexor carpi ulnaris muscle.
- Here, they are covered only by fascia and skin.

## Branches of the Ulnar Artery

### Anterior Ulnar Recurrent Artery
- This arises from the ulnar artery, just inferior to the elbow joint.
- It runs superiorly between the brachialis and pronator teres muscles.
- It supplies these muscles and anastomoses with the inferior ulnar collateral artery.

### The Posterior Ulnar Recurrent Artery
- This arises from the ulnar artery distal to the anterior ulnar recurrent artery.
- It passes superiorly, posterior to the medial epicondyle of the humerus, where it lies deep to the tendon of the flexor carpi ulnaris muscle.
- It supplies the adjacent muscles and then takes part in the arterial anastomosis around the elbow.

### The Common Interosseous Artery
- This is a short branch of the ulnar artery.
- It arises from the distal part of the cubital fossa and divides into the anterior and posterior interosseous arteries.

### The Anterior Interosseous Artery
- This artery passes distally on the interosseous membrane to the proximal border of the pronator quadratus muscles.
- Here, it pierces the membrane and continues distally to joint the dorsal carpal arch.

### The Posterior Interosseous Artery
- This artery passes posterior between the bones of the forearm, just proximal to the interosseous membrane.
- It supplies the adjacent muscles and then gives off the posterior interosseous recurrent artery, which passes superiorly, posterior to the lateral epicondyle of the humerus and participates in the arterial anastomosis around the elbow.

### The Palmar Carpal Branch of the Ulnar Artery
- This arises just proximal to the pisiform bone.
- It passes across the anterior aspect of the wrist, deep to the tendon of flexor digitorum profundus muscle.
- This branch anastomoses with the palmar carpal branch of the radial artery and forms the palmar carpal arch.

### The Dorsal Carpal Branch of the Ulnar Artery
- This arises just proximal to the pisiform bone.
- It passes across the dorsal surface of the wrist, deep to the extensor tendons, where it anastomoses with the dorsal carpal branch of the radial artery to form the dorsal carpal arch.

### The Superficial Branch of the Ulnar Artery
- This artery continues into the palm as the superficial palmar arch.

### The Deep Palmar Branch of the Ulnar Artery
- This branch passes deeply in the hand, where it anastomoses with the radial artery and completes the deep palmar arch.

### The Superficial Palmar Arterial Arch
- It is formed mainly by the ulnar artery.
- It gives rise to 3 common palmar digital arteries that anastomoses with the palmar metacarpal arteries from the deep palmar arch.
- Each common palmar digital artery divides into a pair of proper digital arteries, which runs along the sides of the 2nd to 4th digits.

### The Deep Palmar Arterial Arch
- This lies across the metacarpal bones just distal to their bases.
- This if formed mainly by the radial artery.
- It is about a finger breadth closer to the wrist than the superficial palmar arterial arch.
- It gives rise to 3 common palmar digital arteries.
CME Category::Cardiology