How To Draw A Bicep

The arm is one of the more difficult areas of the body to draw. It contains many separate muscle groups, and often most have to be indicated for a drawing of a believable arm. This makes for a complex problem: how do we learn to draw the arm well, in the quickest way possible?

My answer on how to draw the arm is to 1) use simplified anatomy 2) understand the function of major groups of muscles, 3) use drawing construction process that starts with the brachioradialis muscle and 4) practice drawing the arms a lot from reference.

Your drawings of the arm will depend on how thorough your knowledge of anatomy is and on how much time you spent on practice.

This article is anatomy heavy. You need to know the bones and the major muscle groups and how they move to draw the arm well. There is no way around it. With that said, we will simplify anatomy by grouping many muscles together to make it easier to understand.

The problem with the process of learning the bones, muscles and their function is that it is a technical and tedious process, and it gets confusing fast. This is where this arms drawing tutorial comes in, it is here not just to provide you with the anatomy of the arms (although we will go over it), but to give you real guidance on what to think about, what to focus on when drawing the arms.

How to draw the arm – major forms of the arm

Let's start then with the above drawing of simplified forms of the arm that I drew using an artist manikin.

In this illustration, we have the hand and the wrist, the forearm and the elbow, the upper arm (biceps and triceps) and the shoulder muscle (in blue). The upper arm consists of one bone, and the forearm of two. They connect forming the elbow. The pointy end of the elbow is actually a bone of the forearm moving on a hinge joint. This is the set up we are working with. Below let's get into actual anatomy of the arm.

When discussing anatomy, each muscle has an origin and an insertion. You can think of it as the begining of the muscle and the end. These have an extra meaning though: when a muscle contracts, theorigin pulls theinsertion closer. The origin is the attachment site that doesn't move during contraction, and the insertion does.

Anatomy of the Upper Arm

The bone of the upper arm – Humerus

Humerus:

the humerus is composed of the shaft and two large extremities
the upper extremity articulates at the shoulder, it connects with the glenoid cavity of the scapula (the scapula is commonly referred to as the shoulder blade)
the lower extremity articulates at the elbow, connecting to the radius and the ulna

Muscles of the upper arm – Brachialis, Biceps, Triceps

Brachialis:

Origin: anterior distal half of the humerus, this muscle lies beneath the biceps muscle on the humerus bone.
Insertion: connects to the ulna at its lower half, more specifically at the ulnar tuberosity and the anterior surface of the coronoid process
Action: Flexes the forearm at the elbow

Biceps (short and long head)

Origin: supraglenoid tubercle of the scapula (shoulder blade)
Insertion: the biceps comes down the humerus bone turning into a tendon as it descends and connects to the radius, to the radial tuberosity and bicipital aponeurosis
Action: Flexes and supinates the elbow (elbow bending biceps flex), and flexes forearm.

How to draw the arm - biceps — Biceps – sits on top of the brachialis muscle

Triceps, medial head

Remember that all three heads of the triceps find their insertion at the elbow end of the ulna bone.

How to draw the arm - triceps muscles — All three muscle heands of the triceps

Origin: posterior surface of the body of the humerus
Insertion: olecranon of the ulna (the pointy end of the elbow), all three heads of the triceps turn into a common tendon and find their insertion in that same place.
Action: extends the forearm at the elbow

Triceps, long head

Origin: infraglenoid tuberosity
Insertion: olecranon of the ulna (the pointy end of the elbow), all three heads of the triceps turn into a common tendon and find their insertion in that same place.
Action: extends the elbow, abducts the shoulder

Triceps, lateral head

Origin: posterior surface of the body of the humerus
Insertion: olecranon of the ulna (the pointy end of the elbow), all three heads of the triceps turn into a common tendon and find their insertion in that same place.
Action: extends the forearm at the elbow

Anatomy of the Forearm

Update: I made an entire tutorial dedicated to drawing the forearms with anatomical detail, it can be fond here. Below, we will go over the basics.

Bones of the Forearm – Radius and Ulna

Ulna

attaches to the little finger side to the wrist
the olecranon process of the ulna (or its tip closest to the humerus) creates the point of the elbow

Radius

attaches to the thumb side to the wrist
rotates over the ulna when the palm is moved from facing up (supination) to facing down (pronation)

Muscles of the Forearm

Update: I made an entire tutorial dedicated to drawing the forearms with anatomical detail, it can be fond here. Below, we will go over the basics.

Brachioradialis (do not confuse with the brachialis muscle of the upper arm, this muscle has "radialis" in its name, indicating its insertion at the radius).

Origin: Ridge superior to lateral epicondyle of the humerus and the lateral intermuscular septum
Insertion: lateral side of the base of the styloid process of the radius (close to the wrist, little finger side).
Action: flexes the forearm at the elbow

The Brachioradialis has two very important traits that will help us draw the arm in every angle:

(1) its origin at the humerus, is behind the brachialis muscle, this means that it divides the upper arm between the biceps and brachialis at the front and the triceps muscle at the back. When you start drawing the art in different angles from reference, or if you are tracing anatomy images, or look at very muscular images of the arm, you will notice that it is easy to confuse the medial head of the triceps and the brachialis muscle, until you know that brachioradialis folds in between the two.

(2) Brachioradialis at the forearm closest to the wrist follows its insertion in the radius. This means that as the hand turns, and the radius bone rotates over the ulna, the brachioradialis follows the radius, tracking on the thumb side of the wrist. Brachioradialis creates a twist in the forearm since its origin remains put, and its insertion is taken over the ulna by the radius.

Drawing the arm - Brachioradialis — Brachioradialis – here grouped together with the muscle under it: Extensor Carpi – together they are known as the Ridge Muscles.

Extensors Grouped – simplified

Extensors mostly map to the backhand side of the forearm.

Origin: lower third to the lateral epicondyle of the humerus
Insertion: most extensors go up to the fingertips
Action: extends the wrist, extension, and abduction of fingers

draw the arms - extensors — Extensors grouped and simplified

Flexors Grouped – simplified

Flexors mostly map to the palm side of the forearm.

Origin: mostly at medial epicondyle of the humerus
Insertion: mostly inside the hand, base of metacarpals, pisiform bone
Action: wrist flexion, flexion and abduction of the hand, extends fingers

flexor muscles — Flexors grouped and simplified

Triceps and Biceps – Antagonistic Forces of the Arm

So now we have a basic understanding of the main muscle groups. Although I skipped nonessential items, there are three additional muscles we will need to learn to draw the arm well. They are small, but you still need to know about them for drawing the arm, and we will get to them in a bit. First, let's take a look at how the biceps and triceps muscles work when bending the elbow. This knowledge will guide our shapes in drawing.

The muscles at the front of the arm, biceps, and brachialis, bend the elbow moving the forearm up. It this movement the triceps muscles are inactive. The triceps muscles extend the elbow by moving the forearm down, while the biceps is inactive.

When you bend your elbow you use your biceps. When you extend your elbow you use your triceps. The triceps is flexed when the elbow is extended, moving the msucle volume up to the shoulder.

Let's first look at how the biceps works pulling the ulna and the humerus up to the shoulder:

The biceps sits on top of the brachialis muscle:

Let's now look at the triceps extending the elbow:

drawing the arm - triceps flexion — Triceps flexion extend the elbow

The short and long heads of the triceps sit on top of the medial head. Like the brachialis muscle surrounds the humerus bone from the front, the medial head of the triceps surrounds it from the back.

Pronation and Supination

The hand is supinated when the palm is facing up – and you are able to look at the palm of your hand. The hand is pronated when the palm is facing down towards the ground, and you are able to look at the back of your hand.

When the hand is supinated (palm facing up) radius and ulna are parallel to each other. When the hand is pronated (palm facing down), the radius moves over the ulna as the hand turns.

If you find yourself wondering how to draw the hand, here is a detailed tutorial I published on that subject.

An easy way to remember is to always start with the palm facing up (supination). And remember the "R" in pronation to stand for Rotation of the palm down. Radius rotates over the ulna to pronate the hand. Luckily there is no "R" in the word supination or the word ulna so you shoul never confuse the two again!

drawing the arm - supination to pronation — Radius moves over the ulna as the hand turns. *This image is a study from Bridgman's anatomy books.

Remember that as the hand turns, the connections between the bones at the elbow and at the wrist do not change. The radius still connects at the thumb side to the hand, and the ulna at the little finger side.

Radius indicated in color as it rotates over the ulna bone of the forearm

It is very important to understand this "twisting" of the bones for drawing the arm, because as the hand pronates the muscles of the forearm twist with it. This twist in the muscles should be visible in anatomically correct drawings of the arm.

How to understand this movement in the bones of the arm: to replicate this movement with your legs, stand upright and step over your left foot with your right crossing them. Your right leg would represent the radius in that example.

Below is an example of supination: radius and ulna are parallel, palm facing up.

Below is an example of pronation: radius moves over the ulna, palm facing down.

Drawing the arm - radius rotates over ulna — Radius moving over the ulna to turn the hand. Moving forearm muscles with it.

Muscle Groups Review

Before we move further, let's quickly review the location of all the major muscle groups. Try to guess the muscle by looking at the diagram, then match its number to the description below it.

Muscle group review — 1: Brachioradialis
2: Brachialis
3: Biceps (both heads)
4: Triceps (all three heads)
5: Extensors
6: Flexors

Drawing the arm – Brachioradialis Construction

Ridge Muscles of the Arm

In these diagrams, the brachioradialis muscle is indicated. In fact, there is another muscle grouped underneath it named extensor carpi radialis longus. It fits in more with the brachioradialis then with the extensors that we have grouped in the forearm. Together this muscle (extensor carpi radialis longus) and the brachioradialis muscle are called the Ridge muscles because they originate at the lower third ridge of the humerus. However, since we are going over simplified anatomy of the arm, we will focus on the brachioradialis only. It provides us with all the guidance we need to properly construct the arm.

Remember the location of the brachioradialis muscle (simplified) in the diagram below:

Forms of the arm. — This is an important diagram because it simplifies the forms of the arm, and also identifies the location of the brachioradialis muscle – with the origin at the end of the humerus bone and extending to the thumb side of the hand with insertion at the end of the radius bone.
Also note: the extensors are mainly found on the backhand side of the forearm – they twist with the twisting of the hand, and the flexors are found mostly on the palm side.

I am specifically interested in you remembering the brachioradialis because it is the muscle that tucks in behind the brachialis and divides the upper arm into the triceps and the biceps/brachialis sections. Let's examine exactly how it happens in the diagram below.

How brachioradialis splits the upper arm. — Brachioradialis wedges into the upper arm, dividing the triceps and the brachialis/biceps sides of the arm.

Three Small Muscles to Learn to Draw Arms Better

Now that we went over all the major muscle groups, and discussed how brachialis breaks up the border between triceps and biceps, there are only three other small muscles to point out before we can get to drawing the arm.

These are:

anconeus muscle – at the elbow, helps extend the forearm.
coracobrachialis – from the scapula, inserts at the upper portion of the humerus
pronator teres – serves to pronate the forearm, located mainly in the forearm

How to draw the arm - Coracobrachialis — Coracobrachialis – stabilizes the top of the humerus bone at the shoulder joint

Origin: coracoid process of the scapula
Insertion: at the inner side (closest to the body) of the humerus bone, short of halfway down.
Action: draws forward and rotates the humerus outward, as well as assists in keeping the humerus bone in contact with the glenoid cavity of the scapula

Pronator teres – at the base of the Brachialis muscle connecting to the forearm.

Now Let's Draw the Arm

When drawing the arm, I suggest starting with the general structure of the bones and then mapping out where each muscle group fits. When using reference, you should be able to see where each muscle group is on your reference as you are drawing.

Some examples of mapping Brachioradialis (ridge muscles) in different positions when drawing the arm.

Breaking Down the Forms of the Arm

On the diagram above, brachioradialis is indicated in color. Note the location, from it we can construct the entire arm. Brachioradialis divides the biceps (2) and triceps (3). Extensors (4) are indicated under brachioradialis with flexors on the palm side of the wrist (5). Corocoradialis (6) is the "armpit muscle" that stabilizes the shoulder (7) and assists in arm rotation.

Forms of the arm - how shapes change. — This diagram shows how forms change as we move from the shoulder to the wrist. Biceps is indicated at (1) and brachioradialis at (2). Note, the drawing of the forms of the arm on the left is a study from Bridgman's anatomy books.

The Landmarks when Drawing the Arm:

Drawing landmarks of the arm – inside of the elbow – anterior view

On the inside of the elbow two indicating lines are prevalent in drawings of the arm. These lines hug the biceps from each side. On the outside, (1) it is brachioradialis going around the biceps that create this landmark. On the inside, (2) it is the biceps wedging into the pronator teres and flexors that creates the landmark.

Drawing landmarks of the arm – outside of the elbow – posterior view

Lets now turn to the outside of the elbow. Here two landmarks indicating lines are prevalent. The (1) first is the line where the ridge muscles end (as we discussed above, the ridge muscles are the brachioradialis and extensor carpi muscles). Further down closer to the elbow another indicator (2) line is where the extensor group ends. The line from the elbow to the little finger at (2) is a major landmark called the the ulnar furrow. For a detailed tutorial on how to draw the forearms, visit my forearm tutorial at this link.

Final Words on How to Draw Arms

In this tutorial, we reviewed anatomy and some additional important points like pronation and supination, the brachioradialis muscle and how it can be used to construct and draw the arm, and how to recognize various landmarks. Review the diagrams in this tutorial a few times and try to draw arms from reference. If you are looking for good visual reference to practice arms, here is a link to a Pinterest board I created for that purpose.

To summarize how to draw arms well in one paragraph, I would say to you: know the bones and how they move, know the muscles and their origin and insertion points on the bones, then understand how the muscles move, and how they wedge into each other, their location, and their general shape on the surface, then use reference for your drawings and then practice drawing arms a lot. The more you draw arms, the more you will improve at drawing arms over time.