Vessels and nerves of the hand

Definitions & Key takeaways

The arterial blood supply to the hand mainly comes from the radial and the ulnar artery. Within the hand, both the ulnar and radial arteries divide into branches that anastomose into superficial palmar arch and deep palmar branches. The superficial palmar arch gives three branches called the common palmar digital arteries, whereas the deep palmar arch gives off the princeps pollicis artery to supply the thumb, the radialis indicis artery to supply the index finger, and the three palmar metacarpal arteries to supply their other digits.

The hand has superficial and deep veins. On the dorsal side, the superficial veins form the dorsal venous network which drain into dorsal metacarpal veins in the hand, contributing to two major veins in the forearm: the cephalic vein on the lateral side, and the basilic vein that runs medially. On its palmar side, the hand has superficial and deep palmar venous palmar arches, which drain into the deep veins of the forearm.

Finally, the hand is innervated by three main nerves, which are the median, ulnar and radial nerves. The median nerve innervates some of the thenar muscles, the lateral lumbricals, and provides the sensation to the palm, and the distal parts of the lateral 3 and part of the fourth digits. The ulnar nerve innervates most of the intrinsic hand muscles, and provides the sensory innervation to the dorsal and palmar surfaces of the fifth and part of the fourth digits. Finally, the radial nerve does not innervate any muscle in the hand. It provides sensory innervation to the skin of the lateral half of the dorsal part of the hand and thumb. It also innervates the proximal parts of the second, third, and half of the fourth digits, on their dorsal side.

Chapters:

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Introduction0:00–0:33

All hands on deck, everyone. We're taking a deep dive into the blood supply and nerves in the most mobile and dexterous parts of our musculoskeletal system, the hands.
Human hands are supplied by an intricate network of blood vessels and nerves. Which all work hand in hand to deliver the necessary blood supply and coordination in order for the hand muscles to be able to draw, type, suture, climb, and everything else hands do.

Vascular supply0:33–1:13

The hand's blood supply comes entirely from two main sources, the ulnar and radial arteries, which both originate from the brachial artery.
Inside the hand, the radial and the ulnar arteries give off numerous branches and anastomosis, ensuring that working muscles get an uninterrupted blood supply throughout our versatility of movements.
Both the ulnar and the radial arteries enter the hand from the wrist. The ulnar artery travels down the medial forearm and enters the hand medially, while the radial artery runs down the lateral forearm and enters the hand laterally.

Ulnar artery1:13–2:39

Let's look at the ulnar artery first. When entering the wrist, the ulnar artery passes superficial to the transverse carpal ligament, also known as the flexor retinaculum, and enters the hand through a small tunnel called the ulnar canal or Guon Canal.
The ulnar canal has a roof made up by the thickened superficial palmar fascia. A floor made by the transverse carpal ligament, a medial wall consisting of the pisiform and pisohamate ligament, and a lateral wall made up by the hook of the hamate.
The ulnar canal also allows the ulnar nerve to pass through medial to the ulnar artery. After the ulnar artery reaches the hand, it divides into a superficial palmar arch and a deep palmar branch.
The superficial palmar arch is the main termination of the ulnar artery, and starting in the medial part of the hand, it courses towards the lateral part of the hand to anastomose with the superficial branch of the radial artery.
Along its course, the superficial palmar arch gives rise to three branches known as the common palmar digital arteries. Each of these divides into a pair of proper palmar digital arteries which run along the sides of the 2nd to 5th digits deep to the superficial palmar arch.
The deep palmar branch of the ulnar artery completes the medial side of the deep palmar arch by anastoizing with the terminal part of the radial artery.

Radial artery2:39–3:35

In the lateral part of the wrist, the radial artery gives off the superficial palmar branch that completes the superficial palmar arch, and then it curves towards the back of the hand around the scaphoid and trapezium.
Then crosses the floor of the anatomical snuff box, which is a triangular space formed on the lateral aspect of the wrist at the base of the thumb.
The radial artery then enters the palm where it forms the deep palmar arch which travels across the metacarpals just distal to their bases before anastomos with the deep palmar branch of the ulnar artery.
Along this course, the deep palmar arch gives off the princip's pollicis artery, which supplies the thumb. The radialis indius artery, which supplies the second digit or index finger, and may also arise directly from the princeps pollicis artery.
And then finally, the 3 palmar metacarpal arteries. OK, now for a quick break, can you try to remember the direct branches of the superficial palmar arch?

Quiz3:35–3:55

All right, now, let's look at the veins of the hand. The hand has the superficial veins, which run close to the skin and the deep veins which run deep in the tissues alongside arteries.

Venous drainage3:55–4:56

Some of the superficial veins strain the dorsum of the hand, so they're called, get this, the dorsal venous network. The dorsal venous network starts as dorsal digital veins in the fingers, which drain into dorsal metacarpal veins in the hand.
As they move, these veins form the dorsal venous network which then contribute to the two major veins in the forearm the cephalic vein on the lateral side and the basilic vein that runs medially.
In the palmar part of the hand, the veins of the hand converge to form superficial and deep venous palmar arches. Which run with the superficial and deep palmar arterial arches.
Both these arches drain into the deep veins of the forearm. Alright, now let's switch gears and talk about the nerves of the hand.

Innervation4:56–5:09

The hand is innervated by 3 main nerves, all of which enter the hand from the forearm. The median, ulnar, and radial nerve.

Median nerve5:09–7:08

At the wrist, the median nerve gives off the palmar cutaneous branch right before entering the hand. This branch passes superficially to the flexor retinaculum and enters the hand to provide sensory innervation to the skin of the central palm.
Now, the median nerve itself passes through the carpal tunnel, which is its narrow passageway in the wrist, consisting of a concave bony arch formed by the carpal bones with a thick connective tissue roof, the transverse carpal ligament or flexor retinaculum.
The carpal tunnel is bounded laterally by the tubercles of the scaphoid and trapezium and medially by the pisiform and the hook of the hamate.
The median nerve traverses through the carpal tunnel alongside 9 tendons from the flexor muscles of the forearm. These are the tendon of the flexor pollicis longus, 4 tendons of flexor digitorum profundus, and 4 tendons of the flexor digitorum superficialis.
Inside the hand, the median nerve gives off the recurrent branch and the medial and lateral branch. The recurrent branch provides motor innervation to the muscles of the thenar compartment, namely the opponent's pollicis, the abductor pollicis brevis, and the superficial head of the flexor pollicis brevis.
While the medial and lateral branch provide the motor innervation to the lateral two lumbercles. A simple mnemonic to summarize the motor innervation of the median nerve is loaf.
Which is lateral two lumbrcles, the opponent's pollicis, the abductor pollicis brevis, and the flexor pollicis brevis. The median nerve also provides sensory branches to the whole palm or skin.
Both the lateral and the medial size of the 1st, 2nd, and 3rd digits, the lateral half of the 4th digit, and the dorsal distal halves of these digits.

Ulnar nerve7:08–8:34

Now, for the ulnar nerve, first, it gives off the dorsal and the palmar cutaneous branches in the forearm, which cross the wrist independently.
The dorsal cutaneous nerve branch perforates the deep fascia and runs to the back of the wrist to get in the dorsum of the hand.
Inside the hand, the dorsal cutaneous branch divides into two dorsal digital branches, which provide sensory innervation to the back of the 5th digit plus the medial half of the 4th digit.
The palmar cutaneous branch crosses the wrist and provides sensory innervation over the skin on the medial side of the palm.
The ulnar nerve itself crosses the wrist through the ulnar canal, medial to the ulnar artery. After it arrives inside the hand, it divides into the superficial and the deep branches.
The superficial branch provides cutaneous innervation to the palmar surface of the 5th digit and medial half of the 4th digit, while the deep branch provides motor innervation to the 3 hypothenar muscles which are the abductor digiti minimi, flexor digiti minimi brevis, and opponent's digiti minimi.
And also two medial lumbricals, all of the dorsal and palmar interossi, the abductor pollicis, and the deep head of the flexor pollicis brevis.
Finally, there is the radial nerve which enters the hand by piercing the deep fascia at the dorsum of the wrist via its superficial branch.

Radial nerve8:34–8:56

It provides sensory innervation to the skin over the lateral 2/3 of the dorsum of the hand and thumb and the dorsal proximal parts of digits 23, and lateral half of the 4th digit.

Quiz8:56–9:14

All right, what if you hit the pause button and see if you can remember the muscles innervated by the median nerve? All right, as a quick recap.

Review9:14–11:31

The ulnar artery enters the hand through the ulnar canal and forms the superficial palmar arch, which is completed on the lateral side via an anastomosis with a branch from the radial artery.
The superficial palmar arch gives 3 common palmar digital arteries which supply the 2nd to 5th digits. The radial artery enters the dorsum of the hand by crossing the floor of the anatomical snuff box.
And then enters the palm where it is the main contributor of the deep palmar arch, which is completed on the medial side via an anastomosis with a branch of the ulnar artery.
The deep palmar arch gives off the princip's pollicis artery that supplies the thumb. The radialis indisis artery that supplies the index finger, and the palmar metacarpal arteries.
The superficial veins in the dorsum of the hand form the dorsal venous network which converge into the cephalic vein on the lateral side and the basilic vein medially.
On the palmar side, veins of the hand form superficial and deep venous palmar arches which drain into the deep veins of the forearm.
The median nerve enters the hand through the carpal tunnel. Inside the hand, it gives the recurrent branch, which provides motor innervation to the thenar muscles, and the medial and lateral branches, which innervates the lateral two lumbrcles.
The median nerve also provides sensory branches to the palm or skin, both sides of the first three digits, the lateral half of the fourth digit, and the dorsal halves of all these digits.
The ulnar nerve crosses the wrist inside the ulnar canal. Inside the hand, it splits into a superficial sensory branch and a deep motor branch.
Finally, the radial nerve enters the hand from the lateral side and provides sensory innervation to the skin over the lateral 2/3 of the dorsum of the hand and thumb.