The biceps is one of the best-known, but also most misunderstood muscles, as it is far more complex than a single muscle. In fact, it consists of several heads and is supported by important accompanying muscles. Thus, the biceps is a complex unit with diverse functions and appearances.
Whether you're aiming for bigger arms, more strength, or a smarter workout, understanding biceps anatomy is crucial for targeting the right muscles, increasing your strength, and building big, powerful-looking arms. In this article, we'll explain the individual parts of the biceps and how you can train each one more effectively.
The anatomy of the biceps brachi muscle
The biceps brachii muscle is the largest of the three muscles in the upper, forward-facing part of the arm. It is a complex muscle with a long and a short head. Besides movement, it plays an important role in supporting the head of the humerus in the shoulder joint. Let's take a closer look at the two heads.
The long head of the biceps
The long head originates at the supraglenoid tubercle of the scapula and then runs together with the short head across the front of the elbow, where it tapers into a single tendon that inserts at the radial tuberosity just below the elbow. We see the long head as the peak of the biceps when we flex our arms. The appearance of this peak is primarily genetically determined, particularly by the length of the muscle belly and the tendon insertion points.
While the biceps brachii (long and short heads) plays a crucial role in elbow flexion and forearm supination, it is of secondary importance for shoulder movement. It is important to note that the triceps brachii acts as the primary antagonist of the biceps, responsible for elbow extension. This muscular balance is essential for smooth, controlled arm movements.
Shoulder movements such as adduction and abduction are primarily controlled by other muscles, especially the anterior deltoid for flexion and abduction. While the long head of the biceps contributes to stabilizing the shoulder joint, particularly during overhead raises, it does not cause abduction. Adduction (bringing the arm towards the body) is primarily performed by the coracobrachialis muscle, not the biceps.
The short head of the biceps
The short head also originates from the scapula, but this time at the coracoid process. After merging with the long head and tapering over the front of the elbow, it inserts as a single tendon at the radial tuberosity.
The short head is far less visible than the long head, but no less important, as it contributes to the biceps' width. The short head's primary function is also elbow flexion, with less significance for shoulder flexion and adduction. In this respect, it acts somewhat opposite to the long head, as it is not responsible for abduction (drawing the arm away from the torso), but rather for adducting the arm towards the torso.
Interesting fact: In about 30% of people, there are variations in the origin of the biceps, with 2 to 5% of people having up to 3 to 7 origin points instead of just 2.
The biceps tendon and its insertions
While the two heads of the biceps fuse and terminate in a single muscle belly, their tendons run along two different paths. The tendon of the long head passes through the shoulder joint and the biceps groove of the humerus, while the tendon of the short head runs alongside the tendon of the coracobrachialis muscle. They meet further down the arm, but in most people the tendons remain separable.
Another interesting fact: A small minority of the population has two adjacent tendons, both of which attach to the radius.
Related muscles that influence the appearance and function of the biceps
The biceps brachii muscle may be the star of the show, but it doesn't work alone. Two other upper arm muscles influence the function and appearance of your biceps. These two are the brachialis and the coracobrachialis.
The brachialis muscle
The brachialis muscle is an important muscle because it supports and stabilizes the biceps brachii when the arm is flexed. The brachialis is always engaged when you raise or lower your forearm – it generates 50 to 60% of the flexion force, while the biceps brachii contributes about 30 to 40%. However, this doesn't mean that the brachialis is stronger than the biceps, but simply that it is mechanically more efficient at flexing the elbow.
Targeted training of the brachialis with hammer curls, reverse curls and neutral grip exercises emphasizes the tip of the biceps, as the brachialis muscle presses down on the biceps from below.
The coracobrachialis muscle
The coracobrachialis muscle runs over the shoulder joint, not the elbow, and plays a minor role in shoulder flexion or arm adduction. So, if you have a Injury to the coracobrachialis muscle If you had that, you could probably still perform overhead and pressing movements, even if they would be more difficult.
This is how the biceps works
The biceps crosses two joints, enables movement in multiple planes, and supports upper body function. When they work together, they have the following main functions:
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Elbow flexion: The biceps shortens concentrically as it generates force to flex the elbow joint, bringing the forearm and upper arm closer together.
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Supination: External rotation of the forearm, with the palm facing upwards (as when turning a doorknob). This is made possible in part by the 90-degree rotation of the muscle, as it is connected to the radius.
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Shoulder flexion: Raising the arm in front of the body.
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Shoulder stabilization: Studies have shown, that the long head plays a role in the stability of the shoulder joint during movement, although this is mainly passive support; primary stabilization is provided by the rotator cuff muscles.
Interestingly, the two heads often produce opposing movements:
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The long head supports abduction (arm away from the body).
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The short head supports adduction (arm towards the body).
This makes targeted training of both heads an intelligent strategy for the complete development of the biceps.
Tips for biceps training to work both heads
You don't need 20 different curl variations, you need a smart plan. These training tips will help you isolate the long head, short head, and brachialis to achieve optimal results with biceps exercises.
Varying handle width
One of the simplest methods to appeal to different heads is to vary the grip width.
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When you perform barbell curls with a narrower grip, the long head on the outside of the arm is activated, which improves the appearance of the muscle.
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A wider grip activates the short head more strongly, which increases the width of the muscle and gives it a fuller appearance.
You can also vary your grip width on a pull-up bar or during biceps training with calisthenics to train each head separately.
Elbow position
The positioning of the elbow during curls can also be used to specifically train the different muscle heads.
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When your elbows are positioned slightly in front of your upper body, the short head is maximally activated.
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When your elbows are in line with your torso, this exercise is excellent for the long head of the biceps, as it is maximally activated.
This also helps to reduce the strain on the shoulders while simultaneously training different areas of the biceps.
range of motion
The range of motion is also important. The short head of the hamstring is more active in the second half of a curl movement, while the long head is more active at the beginning of the range of motion. This means you can target each muscle individually by performing partial curls with dumbbells or on a bench press. Speediance Gym Monster 2 you do.
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The lower half of the curl movement, up to about 90 degrees, is ideal for activating the long head.
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The upper half of the curl movement, from about 90 degrees to full contraction, leads to better activation of the short head.
The degree of supination
Supination occurs at the radioulnar joint in the forearm when the palm faces forward, while pronation is the movement where the palm faces backward. Varying the degree of supination can also activate the different brainstems.
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Supinated grip (palms facing up): The long head is more active. To train the long head, we recommend traditional curls with full palm rotation upwards.
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Neutral or pronated position (palms facing inwards/downwards, thumbs pointing forwards): The short head and brachialis are more strongly activated. Choose hammer curls or reverse curls to train the short head.
Address the brachialis
As mentioned previously, the brachialis is a lesser-known but no less important muscle located beneath the main belly of the biceps muscle. It is responsible for enlarging the biceps by pushing it upwards.
Bending the arm in a neutral or pronated position at the forearm minimizes the biceps and maximizes the brachialis. Reverse curls or hammer curls can also be used to train the brachialis.
Frequently Asked Questions
What are the two heads of the biceps?
The biceps is a two-joint muscle consisting of a short head, which originates at the coracoid process of the scapula, and a long head, which originates at the supraglenoid tubercle of the scapula. Both heads converge and insert on the radial tuberosity of the radius.
Which biceps head is most important?
While the long head is responsible for emphasizing the peak of the biceps, the short head gives the biceps more width. However, the underlying brachialis also contributes to emphasizing the peak by pushing the main mass of the biceps upwards. In short, they are both important.
Train your biceps by understanding their anatomy, function, and shape.
Understanding biceps anatomy allows you to train more effectively, improve symmetry, and accelerate arm growth. The biceps may look like a single muscle, but there's a lot going on beneath the surface. From the long head, which provides the peak, to the short head, which provides the width, every part of the biceps and surrounding muscles, such as the brachialis and coracobrachialis, plays a vital role.
With the right technique, you can specifically train these different areas to build stronger, better-shaped arms. By optimizing your grip, adjusting your elbow position, and doing targeted exercises for the long and short heads as well as the brachialis, you can build bigger, stronger, and more defined arms while training smarter, not harder.
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