Arm muscles: biceps, triceps, anatomy and function of the arms

Nothing beats a great pair of weapons. Abs and quads can be great for the beach, but you can turn your head if you spend time developing your arm muscles (biceps, triceps and arms) – even when you’re wearing a T-shirt, tank top or polo.

The muscles in your arms may seem fairly simple, but building them up is nothing more than just curls and kickbacks.

If you learn how these muscles work, you will learn how to strengthen and build them better, so that they look and perform at their best.

Bonus: Knowing the names of these muscles gives you extra tools to compliment your friends (“Hey, Pete, your coracobrachialis Looks great today! ”) And suppressing enemies (“ God, Bob, you really have to do your job palmaris longus. “)

As always, we are here to help.

Your primer on arm anatomy and function is here.

What are the muscles of your arms?

Your arms have four main muscles: the biceps, triceps, forearm flexors and forearm extensors. There are also a handful of other muscles that support these four major ones.

To locate them on your body, stand with your hands on your side and rotate your palate forward. When you look down at your arm, you see Previous (Front) side of your arm; These muscles are in contrast Posterior (Back) muscle.

Front arm muscle

The body has muscles in the front flexors – They pull your edge towards your center, inward. Then Biceps Of the upper arms Curved elbowsAnd Arm flexors On the inside of your hand Flex the wrists and fingers.

Posterior arm muscle

There is behind your arm Extensor Muscles, which perform the opposite function: pull your arms out and back. Then triceps extended (straight) elbowsAnd Arm extensors extend the wrist and fingers.

Now, let’s granulate with the individual muscles of the arms.

The muscles of the upper arm

Your upper arm has four muscles, which are limited by your shoulder joint and your elbow joint.

Three of them are located in the anterior cortex – the biceps brachialis, brachialis and coracobrachialis, whereas the fourth is located in the posterior compartment – the triceps brachii.

1. Bicep brachii

The anterior part of the upper arm contains the iconic biceps muscle, formally known as Bicep brachii, Which makes your elbow joint flexible.

It’s far from the most important muscle in your body – it’s probably not even in the top 100 – but it’s certainly the most showy.

Although the biceps may look like a single mass of muscle, it actually consists of two long sheets or heads: short heads and long heads.

These originate at two points near the shoulder joint and combine to form an attachment point at the top of the arm.

It makes the muscle look like a wrinkled letter V.


Together, the two heads of the biceps perform two main functions:

  • They supinate Your hand, meaning they rotate your hand from the palm-down position to the palm-up position.
  • They Flex On or off, your elbow joint. Think: the pace of weight gain.

How do you build your biceps?

You strengthen and build your biceps whenever you make a pull movement (pull-down, pull-up or row) with the palm of your hand facing upwards.

You also work them with curling movements like dumbbell curls.

Biceps anatomy

If you stand with your arms at your sides and the palms of your hands are turned forward, the biceps’ Long head Located further away from your torso.

It is derived from Superglanoid tubercles, The outermost bone point of your shoulder is located below the deltoid muscle.

The bicep tendon ruptures between two lumps, or Tuberculosis, In the shoulder bone.

This is called Bisepital groove, And it’s a common place of injury: with overuse, it can swell.

Biceps Small head This arises Coracoid process – A point on your shoulder blade that peeks out at the top of your shoulder when viewed from the front.

You can stretch these tendons – and thus the biceps – by attaching your arms to the back of your back, straightening your arms and pressing your shoulder blades together.

About halfway down your upper arm, the two heads come together and end in a single tendon that connects to the inner edge of the radius – the bone that runs along the thumb of your hand.

This is another common injury site among lifters who work with heavy biceps; You know you tore this tendon when the biceps muscle is upwards, like a window shadow.

2. Brachialis

The biceps is below the muscle Brachialis – A long, flat muscle that gives the biceps more shape and height. This is what makes the cool-looking rocks of the muscles on the outside of the upper arm of a well-defined athlete.

The brachialis originates in the outer part of the front of your upper arm and is attached to the ulna bone of your hand.


The biceps may be proud, but because of its size and position, the brachialis is actually the strongest flexible of the elbow joint.

In sports, brachialis helps prevent hyper extension in the elbow joint.

How do you build your brachialis?

Whenever you perform a pull motion (such as a row, pull-down or pull-up) with your hands in parallel, you are emphasizing the brachialis.

You can also focus on the muscles with the hammer dumbbell curls, where your hands are facing each other.

3. Coracobrachialis

Also arising from the corocoid process, and running inside the small head of the biceps, a lesser known muscle called coracobrachialis.

It is attached to the inside of the humerus bone and is activated when you press your upper arms down and towards your torso (e.g. when you do a deep exercise). Small, but important!

4. Triceps

Your upper arm is behind triceps, A three-headed muscle. Among well-defined athletes, the triceps form the shape of a horseshoe behind the upper arm.

Each of the three heads of the triceps originates in a distinct place.

Then, the head is assembled, ending in a single tendon that remains attached Alecranon – The last part of the ulna bone in your hand that forms the nabi point of your elbow.


The role of the triceps is the opposite of the biceps: it extends your arm to the elbow joint.

How do you build your triceps?

The triceps work any compound step where you extend your arm under load. Think: overhead presses, bench presses, push-ups.

You can also work directly with Tricep Pushdown, Kickback and Lying and Overhead Tricep Extensions.

Triceps anatomy

As its name suggests, the triceps has three heads: long, lateral and medium.

The Long head Originates from the scapula (shoulder blade) and crosses both shoulder and elbow joints before ending in olecranone.

Reach the top of your hand and stretch this muscle by bending your elbows.

The Lateral head The triceps form a comma-shaped groove on the outside of the back of your upper arm. In very muscular people, it looks like a croissant.

The lateral head originates from the humerus and joins your other triceps head with about two-thirds of the way down your upper arm before moving to the elbow.

The Middle head, The deepest of the triceps muscles, in the back of your upper arm bone, arises about one-third downwards and moves to the back of your upper arm before joining the other head and attaching to the elbow.

Like the bicep tendon, the lower tricep tendon can rupture at the elbow.

If this happens, the triceps may clump towards the shoulder and it will be difficult or impossible to straighten the arm.

The muscles of the forearm

Like the upper arm muscles, the frontal muscles can be divided into two parts:

  • Flexor, which is on the inside of the arm and bends the wrist forward.
  • extensors, which bend the bend to the outside and turn it backwards.

1. Arm flexor

Standing with your arms at your sides and the palms of your hands, you can see the knot in the elbow closest to your body – also known as the funnel bone – from where these muscles begin.

This is a common injury site: “golfer’s elbow” or inflammation in the protrusion of that bone occurs when you overwork the flexor muscles.


As a group, the flexors of the inner arms of your arms flex your wrists forward and rotate your arms from a palate-up position to a palate-down position.

How do you build your forearm flexors?

Whenever you do an exercise that challenges the grip: pull-ups, rows, farmer’s walks, curls, or grip and grab something heavy.

To focus more on these muscles, climb and hang from the monkey bar, hold a tennis ball or racquetball, perform wrist curls, or work with a spring-loaded gripper.

Anatomy of arm flexors

The three layers of muscle form the anterior flexor group: the superficial group originating from the funnel bone The wrists are flexible The Palmaris Langas, The Flexor Carpi Radialis, And pronator terrace.

All four of these muscles are long and wired and help to flex and prone the wrist.

There are a few more muscles below this surface level of the front muscles of your hand, which work together to clear your fingers and thumbs.

The main one, flexor digitorum superficialisThe tappers turn into four small tendons that run through the carpal tunnel – the bottom of the tissue band along the base of your palm.

Then, another layer is performed on the palm of your hand and attached to your fingers to help the first two joints become flexible.

2. Forearm Extensors

To find these bad guys, again bring the palm of your hand to the front – the outermost knot on the outside of the elbow will be the main point of the front extensions.

With excessive use, this point of attachment may swell, leading to a condition Lateral epicondylitis, Or “tennis elbow.”


These muscles stretch your wrists, fingers, and thumbs and help keep the wrists supine (it palms up).

How do you build your forearm extensors?

When you perform curls, rows and pull-ups with an underhand grip, your front extensions see a lot of action.

To work these straight, try wrist extensions using a light dumbbell,

If you are really passionate, you can draw the tips of your fingers together, wrap a tight rubber band around them and pull your fingers together against the force of the band.

Forearm extensor anatomy

Like the muscles inside your arm, the extensions are long and wired, running along the length of your arm and attached to the fingers.

The largest of these muscles brachioradialis: Unlike the muscles of your other hand, it originates from the upper arm and is attached to the outside of your wrist and helps to bend your elbow, thus making it a flexor (like a biceps) instead of an extensor (like the other muscles around it). .

The brachioradialis has several similar, smaller muscles that help the wrist expand and rotate: Long extensor carpi radialis The Extender carpi radialis And extensor carpi ulnaris.

It helps to stretch your fingers – or open your hands – either Extensor And Extensor of the little finger.

Think it for the Latin name? There are literally dozens more in the front arm.

The fingers and toes, of course, are capable of all kinds of delicate, complex movements, at least not because of the many nervous and muscular superhighways running in and out of them.

We’ve covered key players, but for dedicated anatomists, there’s much more to study.

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