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How to Draw the Knee, Bent, (and straight), Step-by-Step!

Gvaat’s studies (from photo reference and Michelangelo drawings)

Once you attempt to draw the knee for the first time, it is does not take long until you begin to wonder what all of the bumps on the knee actually are.

In this tutorial on drawing the knee, I’ll show you exactly what all those bumps are. We will cover anatomy and then attempt to draw the knee with a few easy to follow examples.  

So how to draw the knee?

To draw the knee, begin by visualizing the bones and tendons underneath to help with the placement of landmarks. Then draw the quadriceps muscles, and indicate the patella and its tendon down to the lower leg. Finally, draw in the hamstrings covering the calves at the back of the knee.

When it comes to drawing the knee, a picture is worth a thousand words. Don’t worry about the anatomy too much at the moment, we will go over it together with plenty of visual examples!

On the left illustration, we can tell the medial (inner) from the lateral (outer) sides of the leg. We can tell mainly because the fibula is on the lateral side. Also notice, how the calf muscle sits higher on the lateral side of the leg. Another way to tell is to look at the direction of the quad muscles, they follow the femur bone and move inward from the hip down.

To really improve at drawing the knee, we need to go over important anatomical landmarks. The good news is, once you know them, you’ll know them forever. So it is a little bit of learning now, but a lot of time-savings for your knee drawings going forward.

At the end of this tutorial, we will go over the drawing of the knee step-by-step and I provide some comments regarding what to focus on.

Without further ado, let’s get to it!

Anatomy of the Knee for Drawing

By understanding the anatomy of the knee we can infer about what is happening underneath when we draw the knee bent or straight. We can then know what to look for when drawing the knee from reference, or we can even draw the knee from imagination.

The quadriceps muscles all join into the same tendon over the patella bone.

Understanding the Tibular Tiburosity and the Patellar Tendon for Drawing

Different between epicondyle and condyle of a bone: a condyle is the smooth bit of the bone that is engaged directly in the joint, while the epicondyle is the outer pointy bit of the same bone.

The tuberosity of the tibia is an elevation on the proximal anterior aspect of the tibia,  just below where the anterior surface of the lateral and medial tibial condyles end.

So what does this mean for drawing? Well, it is a bump or a bony lump on the top front of the tibia, where the patellar tendon attaches.

Together with the patellar tendon, the tibial tuberosity creates a very visible bump on the surface that can sometimes look like a second kneecap underneath the actual kneecap.

The kneecap is enveloped in tendons descending down from the quadriceps muscles. Muscles of the quads join together in the quadriceps tendon and then reach down to the patella. From there, a tendon from the patella (patellar tendon) moves down to the tibial tuberosity where it attaches.

All of this creates an illusion of another kneecap under the kneecap, in reality, it is a tendon-type mass attaching at an elevated bump on the front of the tibia.

Bones Involved in the Knee Joint

We need to identify four bony bits to draw the knee well. The (1) femur, extending from the hip to the knee, the (2) tibia extending from the knee to the foot, the (3) fibula following along the tibia on the outer side of the leg, and the (4) patella or the kneecap protecting the knee joint.

Let’s look at each visually so that we have them later for reference when we draw the knee.

How to raw the legs - structure
We looked at this image when in my leg drawing tutorial, find it here.

It is worth another look to get a general overview of what we will review.

Let’s zoom in to the knee joint since we are focused on learning to draw the knee:

Femur bone indicated in violet – extends from the hip to the knee, articulation at the knee, epicondyles, and condyles (the thick bony tips) protected by the patella (kneecap).
Tibia bone indicated in violet. The lateral (outside) side of the leg is on the left in this illustration.
Fibula indicated in violet. Attaches on the lateral side of the tibia bone.
Patella or knee cap – protects the knee joint. Covered with tendons moving from the top of the leg to the tibia.

The patella or the knee cap is the major landmark of the knee. Regardless of the stylization of the drawing of a knee, it is most often indicated, even if sometimes with just a couple of lines (see my examples at the end of this tutorial).

  • The patella functions to help the quads extend the knees and to protect the femur and the knee joint when the knee is flexed;
  • It is housed inside the quadriceps tendon inserting into the tibia;
  • The patella is somewhat above the level of the joint formed by the femur and the tibia meeting at the knee;
  • The joint between the femur and tibia is just below the patella bone. On each side of the patella are the medial and lateral epicondyles of the femur and the tibial epicondyles are right underneath.

Keep the above pointers in mind when you draw the knee!

Muscles of the Back of the Knee

Study by Gvaat, after Peter Paul Rubens (lateral – outside of the leg).

With the image above, let’s talk a little about the back of the knee.

Looking at the back of the leg, we find three major muscle masses: the glutes, the hamstrings, and the gastrocnemius muscle also known as the calf.

The gastrocnemius (calf muscle) as it wedges into the back of the knee is surrounded by the hamstrings on each side.

So when you draw the knee from the side or in 3/4 view, you will indicate that the hamstrings overlap the calf muscles and not the other way around.

From the gastrocnemius on the lateral side, as we move to the front of the tibia, there are four separate muscle strips that can become visible depending on person and position (soleus, peroneus longus, tibialis anterior, and the extensor digitorum longus) each is indicated on the image above).

If you are opting in to draw anatomically detailed figures in your drawings, then you will definitely need to study these muscles more closely.

Drawing Bent vs Straight Knees

Straight vs bent knee, Gvaat’s study.

The biggest difference between drawing bent and straight knees comes down to how much of the bone is visible at the surface.

When bent, the epicondyles of the femur and tibia become very prominently visible on each side of the knee – spanning the entire width at the front, and making the shape boxy and angular.

When straight, the femur and tibia are still at the surface but not pushing out as much, while you will see the bumpy bits of their epicondyles, the overall shape of the knee will be dictated by the muscles.

Try to bend your knee in front of the mirror, and you should see a more boxy shape emerge as the condyles of the femur become exposed at the end of the bend.

Outer side (lateral) of the leg. Laterally, the top of the fibula is visible.
Study by Gvaat – after George Bridgman (left – knee joint lateral view, and right – knee joint medial view).

In the diagram above, we see how the muscles of the quads come together over the patella in the quad tendon.

This tendon is fairly flat on the surface unlike the quad muscles themselves. So look for quad muscles to bulge and protrude and almost hang over the tendon, especially in muscular figures.

Surface of the tibia in the inner knee is covered by the ‘goose foot’ tendonds from three muscles – gracilis (adductor of the hip group), semitendinosus (hamstring group) and the sartorius. Their continuation is visible in the line overlapping the calf muscle on the medial side.

Medial (inner) view of the leg.

These three muscles are sometimes called the ‘tripod muscles’ while the tendons they form at the knee are sometimes referred to as the ‘goose foot’ due to the resemblance created by their overlapping connections.

Drawing the Knee – Examples

We covered relevant muscular and skeletal anatomy so far in an effort to gain insight into drawing the knee.

There is always more to learn with anatomy, but I hope you find what has been provided helpful.

Let’s now draw the knees together with what we learned:

In this video you can follow how each example drawing was developed. You will see that I usually start to draw around the quad area, as I try to visualize the entire leg (and knee) before I put it down on canvas.
Gvaat’s study. Patella (knee cap) indicated as a small round shape, directly underneath it patellar tendon moving to the tibia also indicated.

In the above image, I try to place the bones to assist in visualizing the placement of landmarks. Notice how the femur bone moves to the outside as it ascends to the hip joint.

Also, notice how I indicated the bones (ends of the femur and tibia) to be fairly large in the knee joint. The bones in this section basically span from one side of the leg to the other. While this is not obvious standing up, it is obvious when you bend the knee.

When the knee is bent, the box like shape of the femur and tibia epicondyles define the shape of the knee itself.

Gvaat’s study. The short strokes at the knee indicate the bottom edge of the patella
Notice that the femur bone descends down to the knee at an angle from the outside in. Fibula on the leg left to us is hidden out of view by the tibia.
In this knee drawing, I place a single mark to indicate the knee cap, and one more to indicate the patellar tendon moving down to the tibia.
Left image shows the knee from the back. Notice two lines indicting hamstrings hugging around the calf muscles.

Drawing the Knees – Step-by-Step Overview

Next, let’s take an example out of the video above. I’ll walk you step-by-step through my knee-drawing process.

Step 1 – drawing knees

Here I started with the outline of the quad muscles. I think it can make more sense to start with the skeletal structure of the legs first, as I demonstrate in my leg drawing tutorial which you can find here. However, keep in mind that as I draw this example, I have the structure in my mind and visualize the entire drawing on paper, line-by-line.

Step 2 – drawing knees

Here I added hamstring muscles outline on the back. These marks now define the thickness of the leg and the shape of the upper portion that will descend into the knee.

Step 3 – drawing knees

In this step, I drew in the knee joint, and the overlap of hamstrings over the calves.

Step 4 – drawing knees

I then proceeded to draw in the patella (kneecap). Note on the top right of the patella in this drawing, is a quad muscle that sits lowest on the front of the leg above the knee – vastus medialis – so-called since it is located on the medial side (inside) the leg. (To explore all the large muscle groups of the leg, follow my leg drawing guide at this link.)

Step 5 – drawing knees

Here I further correct the calf muscle, making sure it sits higher on the outside of the leg, and begin to draw in the other knee

Step 6 – drawing knees

Here, as I draw in the second leg and knee joint, I compare it with every mark I make to the first. I do this to make sure the angles and proportions are believable. Note that it could be beneficial to block in the entire form and angles before you begin detailing.

Step 7 – drawing knees

Now I can indicate the patella on the left leg. You will see that I indicated the patellar tendon joining the tibia on both knees as well.

Step 8 – drawing knees

Here is the final sketch, where I darkened the outlines to provide an easier read of the overall shape of the drawing.

I hope you found this tutorial on how to draw the knees useful! Try to draw the knees yourself! If you are wondering about how to draw the legs next, check out my tutorial by clicking the link here.

As always, you can leave me feedback by following this link.