The Hand

This page includes all of my most important information about the hand. I’ll get you up to speed on the important anatomy, the types of conditions that affect the hand, and the basics of how to care for your own hands. The goal of this page is to provide you with the basics so you can build from here, mastering whichever subtopic you would like as it relates to your health. An informed patient makes informed decisions — let’s work together to heal your hand.

At the bottom of this page, please find a complete list of all the articles I’ve written on the hand and the various conditions that affect it.

The Amazing Hand

Most advances attributable to modern society can be traced back to the human hand.

Don’t believe me? A full 25% of the motor cortex in the human brain is dedicated solely to the function of the hand.

Whether cutting an apple or traveling to the moon, the human hand is perfectly evolved to manipulate tools with both strength and dexterity. We are the only primate with thumbs long enough to easily reach each of the other four fingers. While that allows the fine motor control needed to tighten a screw, we are also able to carry our own body weight through the tips of only a few fingers at a time — a formidable combination of brains and brawn!

Before I close my love letter to the hand, consider whether you’ve ever had a hand injury. Even a bad papercut on one finger. And recall what it was like to lose the use of a hand or a finger, even if just for a few days.

It’s remarkable what we do with our hands day in and day out, and it’s not an exaggeration to say that we wouldn’t be the species we are today without them.

Basic Hand Anatomy

Bones

The human hand is made of 19 bones, 14 of which are in the fingers. Each finger has 3 bones, with the exception of the thumb, which only has 2. At the base of each finger/thumb sits a metacarpal, bringing the total to 19. As with the rest of the body, the bones provide the skeletal structure on which the rest of the tissues are anchored.

Tendons

Nowhere else in the body is there such a specialized, intricate web of tendons carrying out important functions. Tendons are the functional unit of a muscle. In short, a muscle contracts to perform work. The end of each muscle narrows into a white, tubular tendon that attaches to bone. It is through this tendon that the contraction of the muscle can exert its effect on the skeleton. While the reality is far more complex, it is reasonably accurate to think of each finger as having 2 flexor tendons (tendons that help bend the fingers into a fist- and again, the thumb is different and has only 1) and 1 extensor tendon to straighten the finger.

Nerves

Careful if you get a hand surgeon talking about nerves. We love nerves and many of us chose hand surgery because of them. We’ve already hinted at the complexity of the hand, and the network of nerves to service that anatomy is equally as beautiful. Again, to keep things simple, imagine 3 major nerves that travel from the brain, exit the neck, and make it all the way to the level of the hand to deliver signals and relay sensation.

Blood Vessels

As with the rest of the body, none of the above works without energy. The circulatory system is responsible for delivering nutrients and removing waste. And again, because the human hand has evolved to take on such an important role, so too has the blood supply to the hand. Nearly every component of the hand has a dual blood supply (just in case that saber tooth tiger takes a swipe).

Basic Hand Function

Entire books have been written on the function of the hand, so let’s focus on the basics. In overarching terms, the hand is designed to sense the world through touch, grasp, and pinch. It also is used to communicate…sometimes more politely than others.

Sensation

Sensation is fairly straightforward. 3 nerves provide sensation in the hand. The median nerve will relay sensation from the palm side of the thumb, index, middle, and half the ring finger back to your brain. The ulnar nerve covers the other half of the ring finger and small finger, both palm and back side. The radial nerve provides sensation to the back of the thumb, index finger, middle finger, and most of the back of the hand.

Grip

Grip starts to get more complicated. But again, at the basic level, the fingers will curl into a fist to grab an object. This is actually first mediated by small muscles in the hand called the intrinsic that bend the metacarpophalangeal (MCP joints). Once those bend, the flexor tendons (remember, there are two for each finger) take over and bend your fingers down into a fist. This sequence allows us to grab large objects, such as curling our fingers around an apple as we pick it from a tree.

Pinch

The final broad category of hand function is pinch. This is all about the thumb. Because of the design of the thumb carpometacarpal (CMC) joint where our thumb hand bone meets the wrist bones, our thumb can swivel nearly 180°. Think of your thumb in a palm-flat position to a pinch position and notice how much it can rotate. Our thumb has evolved to be longer over time, allowing it to easily touch each of the four fingers. The combination of these two characteristics allows us to manipulate fine tools with ease. This quality is one of the key attributes that makes us human, separating us from the rest of the animal kingdom.

Types of Hand Conditions

The “Tunnels”

Tunnels are a common theme in hand and upper extremity surgery. Whether it’s your tendons or nerves, many of these tubular structures pass through narrow tissue planes or ‘tunnels.’ The most common of all is the ‘carpal tunnel,’ which I discuss at length in my section about “The Wrist.”

Read more: The Wrist | Carpal Tunnel Syndrome

Specifically in the hand, the most common ‘tunnel pathology’ we see is called a trigger finger. The flexor tendons that bend your fingers can get caught as they pass through the narrow tunnel system of the palm and digit. Any degree of swelling or inflammation can cause triggering, catching, or even locking as one bends their finger into a fist.

Read more: Trigger Finger

Degenerative

While nobody likes to admit it, we are all losing the battle with time. As we age, our body accumulates damage and wear that it cannot entirely heal. This process is collectively referred to as degenerative disease.

Read more: What is Arthritis?

We see this in the hand as well. The finger and hand joints wear out just like any other joint. Commonly, this occurs in that beautiful thumb CMC joint I described earlier. Because it is so mobile and takes such a load over time through pinching, it is at high risk of wearing out. Thumb CMC arthritis abounds in our patient population, as does arthritis in the smaller finger and hand joints.

Read more: Thumb CMC Arthritis | Finger Arthritis and Mucous Cysts

Lumps and Bumps

Masses and cysts are also frequent offenders of the hand. With the high degree of repetitive use our hands and fingers sustain, coupled with the relative ‘skinny-ness’ of the anatomy, any little mass or cyst is going to be highly visible, painful, or annoying. Imagine a 3mm cyst emerging from your hip joint. Would you ever feel it or notice it way down deep in your thigh? Probably not. Now take the same size cyst and put it in the joint under your fingernail. Ouch!

Read more: Mucous Cysts | Ganglion Cyst

While many of these do not necessarily need to be removed, lumps and bumps are common occurrences in the hand.

Injury

Last but not least is injury. As you can imagine, injuries to the hand come in all flavors. If I had to loosely categorize, I’d put the majority into fractures and lacerations.

Any of the hand and finger bones can break, and they all take on their own character relative to their function and fracture pattern. The treatments range from immediate motion to casting to intricate major surgery.

Read more: Boxer’s Fracture | Jammed Finger

Lacerations are also a big deal in the hand. Again, the anatomy is relatively skinny so important structures exist just beneath the skin. Cutting a nerve or tendon in the hand is extremely common and these injuries can have devastating effects on function. I spend a lot of time and energy getting these injuries treated just right in the field of hand surgery.

Home Care of the Hand

While there’s no way to efficiently encapsulate all that goes into caring for the hand, here are a few basics to get you started.

Motion Is Lotion

Especially in the realm of degenerative or longstanding hand pain, motion is key. The small joints and complex tendon interactions of the hand are highly prone to stiffness.

And hand stiffness is interesting. It is often transmitted back to the brain as ‘pain.’ So a stiff hand will hurt terribly, purely due to the stiffness.

So if you wake up with achy hands or are working through chronic pain, keep those joints gently moving. No need to do anything forceful, but keep everything moving as much as you can and you’ll do yourself a world of benefit.

If It Hurts, Don’t Do It

I realize this sounds ridiculously obvious. But it’s true.

If your hand is injured or hurt to the point that you’re considering seeing a specialist, then it’s time to pay attention. If an activity or motion hurts, either stop doing it or modify it in a way to prevent it from hurting. Consider a brace to help avoid pain.

Mom was right. Listen to your body.

Don’t Ignore Hand Injuries

Because the hand is prone to stiffness and the anatomy is complex, most injuries of the hand do far better when treated early. And for some injuries, this is critical. Take a cut nerve or tendon, for instance. After about 10 days, the chance of successful repair plummets. Take the initiative to get these injuries evaluated in front of a hand specialist as soon as possible!

This goes for seemingly run-of-the-mill injuries too, most notably a jammed finger. While most jammed fingers are no big deal, a few variants can have devastating longer consequences if not treated early. Even if it’s ‘just a jam,’ your hand surgeon will be able to get you safely moving right away, thus preventing all the downstream stiffness and pain that typically accompanies these common injuries.

Read more: Jammed Finger

RICE Therapy

If there’s one thing you learn about caring for your hands (or arms or legs or anything else musculoskeletal), let it be this.

If you have sustained an injury, there are several at-home treatments to start right away before you can get in to see a doctor. Let’s walk through how to treat yourself with what is commonly known as R.I.C.E. therapy.

R - Rest. If your hand hurts following an injury, try to stop using it as much as possible. Even better, obtain a standard Velcro brace from your local pharmacy or a friend. This will immobilize the joints of your hand and allow your injury to rest. While this may not be enough to definitively treat your injury, it will help with the initial stages of pain and inflammation.

I - Ice. It can be very helpful to use ice on the injured hand. Be sure you have a protective layer between the ice and your skin (eg, dish towel, clothing). Do not ice the area for more than 20 minutes at a time. I typically recommend icing in a “20 minutes on, 20 minutes off” pattern.

C - Compression. Of all the stages of R.I.C.E., be the most careful with compression. Some find that some gentle compression feels good after an injury for extra stabilization. In general, we would recommend accomplishing this by using an elastic wrap bandage (Brand example: ACE wrap). However, it is crucial that you don’t stretch the elastic wrap bandage while you wrap. This will provide too much compression, and if your hand swells, you can develop a painful or even permanently damaging condition. If you are interested in using compression, be sure to gently apply the bandage and re-evaluate frequently to ensure it is not becoming too tight with your hand swelling. Never apply compression before going to sleep for the night.

E - Elevation. This is the most important one. I wish this were first in the mnemonic, but then it would spell E-R-I-C. Anyways, elevate, elevate, elevate. The higher the better. When you can, keep the hand above the level of the heart. When that’s not possible, keep your hand above your elbow. Gravity is your friend! The more you elevate your injured hand, the less swelling you will experience. The less swelling you experience, the less pain you will have. This is particularly crucial in the first few days after an injury.

Best Patient Resources

• Hand Care - American Society for Surgery of the Hand

• OrthoInfo - American Academy of Orthopedic Surgeons

• Health Library - Cleveland Clinic

• Mayo Clinic