Do fingers have muscles?

No, the fingers themselves contain no motor muscles — just bones (phalanges), tendons, ligaments, nerves and blood vessels. Every finger movement is powered by muscles in the palm and forearm, which pull on tendons that run into the fingers.

Where are the muscles that move your fingers?

Two sets of muscles move the fingers. About 19 intrinsic muscles sit inside the palm (thenar, hypothenar, lumbrical and interossei groups) and handle fine, precise movements. Around 15 extrinsic muscles sit higher up in the forearm and provide grip strength — they reach the fingers through long tendons that cross the wrist.

How many bones are in your fingers?

There are 14 phalanges in each hand: three in each of the four fingers (proximal, middle and distal) and only two in the thumb (proximal and distal). The whole hand contains 27 bones in total — about a quarter of every bone in the human body sits in our two hands.

How do tendons move the fingers?

Tendons connect muscle to bone. When your brain signals a muscle in the palm or forearm to contract, the muscle shortens and tugs the tendon attached to it. Because the other end of the tendon is anchored to a finger bone, the bone moves — flexor tendons curl the finger inward, extensor tendons straighten it back out.

Why don't fingers have muscles built into them?

Packing muscles inside the fingers would make them bulky, slow and clumsy. Evolution solved that by moving the muscle bellies upstream — to the palm and forearm — and using tendons as remote control cables. The result is a slim, dexterous finger that can still produce a powerful grip thanks to the larger muscles working it from a distance.

How Do Fingers Work If They Don't Contain Muscles?

Table of Contents (click to expand)

The Human Hand
Bones
Tendons

No, your fingers don’t contain any working muscles — only bones, tendons, ligaments, blood vessels and nerves. Every finger movement is driven by muscles in your palm and forearm, which pull on long tendons that run into the fingers and tug the bones like puppet strings. The only “muscles” fingers do have are microscopic arrector pili that make finger hair stand on end.

We use muscles for everything that we physically do. When we move any of our body parts in any way whatsoever, muscles are involved in accomplishing that motion. Indeed, we couldn’t imagine our daily lives without the 600+ muscles in different parts of our body that facilitate a myriad of physical motions and actions.

However, you might be surprised to know that fingers, which are involved in almost all movements of the hands, don’t contain muscles to facilitate movement!

So… how do we extend, flex or curl our fingers if there are no muscles there in the first place?

When we say that fingers have no muscles, that isn’t 100% true. The only muscles fingers have are completely unrelated to motion; they are tiny arrector pili muscles that help make the hair on your fingers stand out straight. Also, we aren’t trying to imply that there is no involvement of muscles in the movement of fingers, only that fingers themselves don’t contain any muscles that control the movement.

Movement in your fingers – which is quite precise – is brought about by the concerted actions of the tendons, bones and muscles that are present in the palms of our hands. Let’s take a look at how it works.

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The Human Hand

The human hand is a very complex structure in itself; it contains a total of 27 bones, which means that almost one-quarter of all the bones in the human body are found in our two hands. Other than bones, the human hand also contains 34 muscles, along with many tendons, nerve fibers and blood vessels, all of which are covered by a thin layer of skin.

Bones

Each finger consists of three bones called phalanges, named in order of their distance from the palm: the proximal phalanx (closest to the palm), the middle phalanx, and the distal phalanx (the fingertip). The thumb is the exception — it has only two phalanges, a proximal and a distal one, with no middle.

Tendons

Tendons connect muscles to bones, whereas ligaments connect bones to other bones. Standard anatomy texts count roughly 34 muscles that control the hand: about 19 intrinsic ones sitting inside the palm itself (thenar, hypothenar, lumbricals and interossei) plus around 15 extrinsic ones tucked into the forearm, whose long tendons reach into the fingers. The two major finger actions — flexing and extending — are powered by the flexor and extensor muscles of the forearm, respectively.

This is the raw information regarding various components of our hands, but now let’s look at how they actually work together to make us do things, such as grip an object, lift a dumbbell or simply point a finger at someone (no pun intended).

The brain is obviously at the helm of every function of the body, so nothing happens unless it’s approved by the brain.

No finger moves without my consent meme

When you decide to point a finger at something, for example, the brain sends a message (an electric impulse) that travels through the nerves, which connect to the muscles present in the palm and forearm. This electric signal commands specific muscles to relax and others to flex/tighten.

Upon contraction of a muscle, a tendon is pulled. Since tendons are connected to muscles on one end and bones on the other, a pulled tendon causes a bone to move and perform specific actions. Therefore, when you want to point a finger at something, the tendons pull on the bones in the index finger, which become taut. And…

obama pointing finger

… this happens.

Every kind of possible action that fingers perform is controlled/regulated by muscles present in the palm and forehand. That’s the reason you can so strongly ‘feel’ those muscles when you grip something tightly or lift something heavy. Fingers may not have muscles of their own, but thanks to the pudgy palm and the firm forearm, they certainly never feel the pang of their absence, do they?

References (click to expand)