How to Draw Forearms with Anatomical Detail, a Step-by-Step Guide
Drawing forearms is a task that at first seems difficult, but with time as you learn what you are drawing becomes surprisingly very fun. Constructing an anatomically correct drawing of the forearm at any angle will become an interesting challenge with the right training.
It is no surprise however, that it is difficult to learn to draw the forearms in the beginning. There are lots of muscles to remember, and they twist and turn depending on the movement.
Before we proceed cautiously into the details of drawing the forearm, here is a short and simple answer on how to draw the forearms for those of you interested in that:
Drawing the forearms requires identifying the rotation of the wrist (pronation vs supination), followed by properly mapping the flexor, extensor, and brachioradialis muscle groups to the skeletal structure underneath.
That is it. What makes drawing forearms difficult is that we must account for the rotation to the muscles and flexion of the elbow. We will talk about all that next!
Gvaat’s forearm drawing tutorial, table of contents:
- Skeletal Structure of the Forearms
- The Muscles of the Forearm for Drawing – grouped
- Pronation vs supination
The Skeletal Structure of the Forearm for Drawing
Let’s first quickly go over the skeletal anatomy of the forearm. There are three bones to know, one connecting from the shoulder to the elbow – that is the humerus bone. And two bones connecting from the elbow to the wrist – those are the ulna and the radius bones.
Now let’s take a closer look at the elbow joint. It is the joint where all three of these bones meet.
The elbow joint is a simple hinge joint where the ulna is surrounded on both sides by the humerus bone. On the outer side of the arm, (lateral side), the radius bone extends from the elbow joint to the wrist.
This is an important thing to remember to draw forearms well, so let’s repeat it together: the radius is on the lateral side, meaning on the outside of the arm at the elbow. Regardless of what happens with the twisting of the forearm (more on that later), the radius stays on the lateral side.
Knowing that the radius is on the lateral side, from the elbow joint drawing above, I can tell that the side with the 2 written on it, is the side closest to the body, or the medial side.
Let’s now take a closer look at the elbow joint from the posterior (back) view. From the drawing above, we can see that the humerus clasps the ulna on both sides.
We can also see bony bits sticking out on each side from the humerus called the epicondyles of the humerus. The one on the inside of the arm, closest to the body, is called the medial epicondyle of the humerus, and one on the outside is called the lateral epicondyle of the humerus.
Epicondyles of the humerus are very important in drawing the forearm, so do note their existence. They are important because major muscle groups originate at those points.
This means that when you draw the forearm, you will approximate where the epicondyles are, and therefore approximate the origins of major muscle groups of the forearm. This knowledge will prove very useful in helping us create anatomically correct drawings of the forearm.
Brachioradialis Group of the Forearm
With basic skeletal structure out of the way, let’s jump into the major muscle groups. There are three major muscle groups of the forearm: the Brachioradialis group (sometimes referred to as the Ridge muscles), the Flexors group, and the Extensors group.
Let’s start with the Brachioradialis group which can lead your construction of the forearm drawing.
The brachioradialis group always extends to the thumb side of the hand. So we know that these muscles travel from in between the biceps and the triceps on the way to the thumb.
This group consists of the Brachioradialis and Extensor Carpi Radialis Longus.
(Yes, the Extensor Carpi Radialis Longus is not a part of the extensor group. At least for drawing, extensor carpi should be grouped with the brachioradialis muscle, since visually their forms appear grouped together, and further, extensor carpi radialis longus appears distinctly separate from the extensor group.)
To get accustomed to drawing forearms, it is important to look at examples and obtain an eye for picking this muscle group out of every forearm reference. Then you can really begin to see what happens with the form as it twists over the bone.
Why do I consider the brachioradialis group the most important in drawing of the forearm? Knowing its location will help map out the rest of the muscles of the arm. If you can properly map the brachioradialis and the extensor carpi radialis longus muscles on the forearm, you’ll be able to find the flexors, the extensors, triceps and biceps locations.
If you are interested in drawing the rest of the arm, including the location, shape and functions of the triceps and biceps groups, check out my tutorial on drawing the arms at this link.
Extensors Muscle Group of the Forearm
Now let’s cover the extensors muscle group of the forearm. There are few muscles in this group, but for now, let’s discuss it as one mass. Extensors extend from the lateral epicondyle of the humerus, travel down the back of the forearm, and weave into the back of the hand.
Remember that we discussed the humerus bone in the skeletal structure section above, and I asked you to note the lateral and medial epicondyle of the humerus.
Here, we see that the extensors, located on the outside of the arm, stretch from the lateral or the outer side, from that bony bit of the humerus (lateral epicondyle) right into the back of the hand.
Flexors Muscle Group of the Forearm
- All flexors originate at the medial (inner) epicondyle of the humerus
So now let’s discuss the muscles on the inside of the forearm – the flexors group. The flexors are always visible with the palm side of the hand.
The flexors originated at the medial or the inner epicondyle of the humerus and continue down the forearm and then weave right into the palm.
They are responsible for the other large muscle bump on the forearm (the first group that creates a large lumpy muscle mass at the top of the forearm is the brachioradialis group we discussed above). The notable difference here is that the brachioradialis peaks closer to the biceps, while the flexors peak at a lower point towards the hand.
Regarding the naming of the extensors and flexors.
At this point, you are probably starting to wonder about the naming of these muscles. The flexors are so-called because they help flex the hand – they help move the palm closer to the forearm, you can palpate these muscles being flexed as you bring your palm in. The extensors help extend the hand, and the engagement of the extensors can also be felt as you extend the hand back.
The pronator teres is a small muscle often visible on the medial side of the biceps. It is worth discussing so that you see it when studying reference, since it often appears as a separate form or a landmark.
Important notes to know about pronator teres:
- Pronator teres originates at the medial epicondyle of the humerus AND coronoid process of the ulna (right underneath the humerus insertion)
- Inserts at radial aspect (outer side) of the radius – at the midpoint
- Short muscle – has little distance to go from origin to insertion
- As it moves towards the insertion point, it dips under the brachioradialis muscles
- It is the muscle that surrounds the biceps medially at the elbow joint
Make a mental note here that the bottom portion of the biceps connects to the radius as it wedges under pronator teres and brachioradialis. For more on how to draw the entire arm, including the biceps and triceps muscles, find my arm drawing tutorial here.
Muscles of the forearm so far, review:
Pronation versus supination – twisting of the hand
Now that we have a good idea of the skeletal structure as well as the muscles that comprise the forearm for drawing, let’s look at what happens with the bones and muscles when you twist your hand.
I purposefully omitted the discussion of pronation until now. It is imperative that you study the bones and muscles mentioned above and come back to this point when you are at least somewhat familiar with their placement.
As we discussed earlier, there are three bones in the arm the humerus, the ulna, and the radius. We also talked about the radius being at the lateral side of the elbow.
Notice how I did not say that the radius is on the lateral side of the forearm, but only the elbow, here is why:
When you twist your palm going from the palm-up position to the palm-down position (ending the motion with you being able to see the back of your hand – palm posterior), during this twisting motion, the radius bone rotates around the ulna.
Wait, what? That’s right, the radius moves over and around the top of the ulna. (See the simplified diagram above)
For the purpose of drawing the forearm, remember that either joint at the elbow and at the wrist remains the same. That is to say, at the elbow, the radius still attaches laterally (outer side), and at the wrist, the radius still attaches on the thumb side, and the ulna still attaches at the little finger side.
As noted, not much is happening at either joint. However, a lot of movement happens in the middle, resulting in the muscles twisting with the bones.
An easy way to think about supination and pronation is to identify the brachioradialis muscle as it always follows through towards the thumb. Even as the forearm twists, it will always map out to the thumb.
Since it originates at the lateral ridge of the humerus, more pronation int he hand will equal more twist to the brachioradialis muscle.
If you want to remember these terms, just remember that the radius is used actively (rotating over ulna) in pronation, and not supination. Both ‘Radius’ and ‘pRonation’ have an R in them (the R can stand for ‘Rotate’), while supination has no R in it!.
Radius = pRonation.
Landmarks of the Forearm
At location 2 on the diagram above, we can see a major landmark called the ulnar furrow.
The ulnar furrow is a long narrow trench, made by the muscles surrounding the ulna on each side.
It is a great landmark for drawing the forearm because it divides the forearm between the flexors on one side of the furrow and the extensors at the other.
At location 3, the mark indicates the passing of brachioradialis over the biceps as it moves up from the forearm into the arm.
We identify the brachioradialis muscle since we are viewing the lateral side of the arm. (Similar mark on the medial side is created by pronator teres moving over the biceps).
You can map a line of the ulna going right from the elbow joint directly to the little finger side of the hand, creating the ulnar furrow landmark on its way there and dividing the forearm between the flexors and extensors.
We spent a lot of time discussing the elbow joint, here is its posterior or the back view. Three bones can be visible depending on position and angle. Keep this in mind when looking at reference as it can get confusing. Remember that humorous clasps around the ulna.
How to Draw Forearms – Construction in Drawing
So far, we discussed the skeletal and muscular structures of the forearm, as well as what happens in supination and pronation of the hand, and finally, we went over important landmarks in drawing the forearm.
Let’s take a moment to discuss the best way to think about drawings forearms.
It is very important to identify angles at which you will be drawing the forearm. Start with the basic structure like in the diagram above, and map out the angles and the bones at the elbow joint.
When you are able to map out the epicondyles of the humerus, you are immediately able to imagine the connection points for the flexors to the humerus and the extensors to the humerus.
In the diagram above, the basic cylindrical shapes are mapped out to identify the angle at which I will be drawing the arm and the forearm.
Once you have the basic shape in your mind (or on paper if you are just starting out with this type of drawing), you can further refine it to include the separation between the ulna and the radius bones. At this step, you can start thinking about pronation and supination, – if the radius is over the ulna or is parallel to it.
Knowing the movement of the radius in your drawing of the forearm will help you map out the rest of the muscles.
Once you have the basic forms, you can start by mapping out the brachioradialis muscle, as it emerges from between the biceps and triceps and extends towards the thumb.
Continue to map out the extensors and flexors accounting for the twist in the wrist.
The best way, and the fastest way, to learn to draw the forearm is to look at and study many examples of drawing and photo reference.
When I say ‘study’, I am referring to looking at an example and replicating it in your sketchbook. There is no substitute for drawing it yourself.
For more detailed anatomy tutorials visit the anatomy section.
This concludes this forearm drawing tutorial. I hope you learned something useful! And if you have, now it’s time to put your newfound knowledge to practice!