Neurovasculature of the upper limb
The upper limb is truly a complex part of the human body. In order to thoroughly understand its structure, the anatomy of the upper limb is broken into compartments, such as regions, bones, joints, muscles, nerves and blood vessels. This compartmentalization helps to focus on the necessary details.
In this page, we are going to discuss the arteries, veins and nerves of each upper limb region; the shoulder, arm, forearm and hand. All together these form the neurovascular compartment of the upper limb.
Upper limb arteries
The main artery supplying blood to the upper limb is the subclavian artery. The trunk of the subclavian artery is continuous throughout the entire upper limb. During its pathway, the artery changes its name based on the region it supplies. Thus the major named arteries of the upper limb are: the subclavian artery, the axillary artery, the brachial artery, and the ulnar and radial arteries.
Arteries of the shoulder
The main artery of the shoulder is the axillary artery. It originates from the subclavian artery at the lateral margin of the first rib and enters the shoulder region. The axillary artery supplies the content of the shoulder and the arm via its six branches that each originate from the trunk of the artery in the following order:
- Superior thoracic artery
- Thoracoacromial, lateral thoracic arteries
- Subscapular, anterior circumflex humeral, posterior circumflex humeral arteries
You can find out more about the axillary artery through the following article and video:
Arteries of the arm
The major artery of the arm is the brachial artery, which continues from the axillary artery at the lower margin of the teres major muscle. The brachial artery ends at the apex of the cubital fossa by giving off the forearm branches; the ulnar and radial arteries.
The brachial artery supplies the content of the arm via its four branches: profunda brachii artery, nutrient artery to humerus, superior ulnar collateral artery and inferior ulnar collateral artery. Find out more about the brachial artery and check out an interesting clinical case in these two articles:
Arteries of the forearm
The forearm region is literally full of muscles, with twenty of them laying within two compartments, all requiring a rich blood supply. The forearm region is thus supplied by two major vessels, the radial artery and ulnar artery. These arteries originate from the brachial artery at the apex of the cubital fossa, with the radial artery descending through the lateral part of the forearm and the ulnar artery through the medial part.
Both arteries give off their main branches within the forearm; with the radial artery giving the radial recurrent artery, palmar carpal branch and superficial carpal branch, and the ulnar artery giving the ulnar recurrent artery, muscular arteries, common interosseous artery, dorsal and palmar carpal arteries.
Learn more about the radial and ulnar arteries with these two amazing articles!
Arteries of the hand
The radial and ulnar arteries both end in the hand, anastomosing with each other. The radial artery mainly supplies the thumb and the lateral side of the index finger, while the ulnar artery supplies the medial side of the index finger and the rest of the fingers. Seems weird how only two arteries supply such a complex structure like the hand is?
Well, these two arteries form two anastomotic arches in the palm, called the superficial palmar arch and deep palmar arch, from which minor arteries to the muscles, digits and joints of the hand originate.
Upper limb veins
Veins usually accompany main arteries, which is also the case here. Since the veins convey blood from periphery to the heart, we’ll discuss them starting from the hand to the shoulder.
The hand has two venous networks that drain it. There are deep veins which accompany the arteries, and superficial veins which anastomose into a dorsal venous network. This superficial network is located at the dorsum of the hand. The basilic vein originates from the medial side of the dorsal venous network, while the cephalic vein originates from the lateral side. The two mentioned veins, basilic and cephalic, are the main veins of the forearm. They are superficially located, with basilic traveling through the ulnar, and cephalic traveling through the radial, side of the forearm. Besides these two, the median forearm vein assists in draining the forearm. It travels through the middle of the forearm. All three veins of the forearm tribute to the brachial veins.
The veins that drain the arm are the paired brachial veins. The brachial veins are deep veins that are positioned like some kind of bodyguards around the brachial artery - one travels along its medial side and the other along the lateral. Their tributaries are the veins of the forearm and the veins that accompany the branches of the brachial artery. All of them together tribute to the axillary vein.
The main vein of the shoulder is the axillary vein, which conveys blood from the shoulder and arm. It begins at the lower margin of the teres major muscle formed from the basilic vein and later the cephalic vein, gathering tributaries within the shoulders. It ultimately becomes the subclavian vein at the lateral border of the first rib.
To get the full picture, check out this article and video tutorial to reinforce your knowlege about the upper limb veins.
Nerves of the upper limb
The upper limb is supplied by a nervous network called the brachial plexus. This plexus is made by the merging of the anterior rami from the lower four cervical nerves and the first thoracic nerve (C5-T1). The plexus is anatomically divided into roots, trunks, divisions, cords and finally, the terminal branches.
Terminal branches of the brachial plexus are:
- The musculocutaneous nerve: innervates the anterior compartment of the arm, including the skin of the lateral side of the forearm.
- The axillary nerve: innervates the deltoid, long head of the triceps brachii and teres minor muscles. Provides sensory innervation for the shoulder joint and the skin covering region of the deltoid muscle.
- The median nerve: innervates the anterior compartment of the forearm (except for the flexor carpi ulnaris and medial half of the flexor digitorum profundus), the thenar eminence (opponens pollicis, abductor pollicis brevis, flexor pollicis brevis), lateral lumbricals, and the skin of the lateral hand.
- The radial nerve: innervates the posterior compartments of the arm and forearm, skin of posterior arm, forearm and the dorsolateral part of the hand.
- The ulnar nerve: innervates the flexor carpi ulnaris and medial half of the flexor digitorum profundus, the hypothenar eminence (opponens digiti minimi, abductor digiti minimi, flexor digiti minimi brevis, palmaris brevis), medial lumbricals, dorsal and palmar interossei, adductor pollicis, and the skin of the medial hand.
Find out more about brachial plexus and its branches with the following articles and video tutorials: