Introduction
Hello and welcome back to our module on anatomical structure. In the last lesson, we established the foundational structure of the figure by learning to draw simplified, three-dimensional representations of the ribcage and pelvis. You practiced seeing these as two distinct, rigid masses connected by the flexible spine, which is the key to creating dynamic poses.
Today, we're going to build upon that foundation. Our learning outcome is to map the major muscle groups of the torso that affect the surface contours. We'll be "draping" the muscles over the bony framework you learned to construct. This is how we move from a structural mannequin to a believable human form.
We won't be diving into a full medical anatomy course. Instead, we'll focus on the large, superficial muscles—the ones that create the visible shapes, bumps, and curves of the torso. Think of it as learning the main "puzzle pieces" and how they fit together.
Part 1: The Muscles of the Front and Sides
Let's begin with the front of the torso. The key muscle groups that define this area are the Pectorals (chest), Rectus Abdominis (abs), External Obliques (sides), and the Serratus Anterior.
To get a dynamic and intuitive introduction to how these muscles look and interact, let's watch a segment from a video by the artist Kaycem.
the COMPLETE GUIDE to drawing TORSOS! [Character Design Bootcamp - Day 7]
In his 'COMPLETE GUIDE to drawing TORSOS', Kaycem provides a clear, practical breakdown of the front torso muscles. He does an excellent job of simplifying the anatomy into manageable shapes and showing how they connect.
Watch the section from 13:05 to 20:55. As you watch, pay close attention to: The fan shape of the pectoral muscles. The location of the abdominal muscles, starting from the 5th rib. The 'zigzag' pattern created by the interlocking Serratus and Oblique muscles.
As you can see, these muscles aren't just flat shapes; they are volumes that wrap around the ribcage and connect it to the pelvis and arms. Now, let's solidify this understanding with a more structured, layer-by-layer approach.
How to Draw the Torso Easier, an Illustrated Guide
The article 'How to Draw the Torso Easier' from GVAAT provides excellent diagrams that build the torso muscles layer by layer on a skeleton. This systematic approach is very helpful for understanding their placement.
Please read the sections titled 'How to Draw the Chest Region' and 'How to Draw the Abdominal Muscles'. The animated GIFs are particularly useful for seeing how each muscle group fits onto the skeleton.
Summary of the Front Torso Muscles:
- Pectoralis Major (Pecs): These are the large, fan-shaped muscles of the chest. They originate from the clavicle and sternum and insert into the upper arm bone (humerus). They create a distinct shelf-like form that wedges under the shoulder muscle.
- Rectus Abdominis (Abs): These are the famous "six-pack" muscles. They run vertically from the lower part of the ribcage (around the 5th-7th ribs) down to the front of the pelvis. They are not a flat sheet; they are segmented and create a series of rounded, blocky forms.
- External Obliques: These form the sides of the torso, wrapping from the lower ribs down to the top ridge of the pelvis (the iliac crest). They are the muscles that stretch and compress when the torso bends side-to-side.
- Serratus Anterior: These are smaller muscles shaped like "fingers" that lie on the side of the ribcage, underneath the armpit. They interlock with the obliques, creating the zigzag pattern that Kaycem highlighted, which is especially visible on leaner figures when an arm is raised.
Part 2: The Muscles of the Back
Now let's turn our attention to the back. The two most significant muscle groups for defining the shape of the back are the Trapezius and the Latissimus Dorsi.
The following video simplifies the back's complexity into a clear, step-by-step construction process.
Back Anatomy Simplified! (Figure Drawing Structure Tutorial)
The channel Pencil Power! offers a fantastic tutorial titled 'Back Anatomy Simplified!'. It focuses on drawing the large, simple shapes of the back muscles, which is exactly our goal.
Watch from 03:10 to 12:48. The instructor builds the back anatomy step-by-step: First, he adds the Trapezius muscle over the scapula (shoulder blades). Next, he adds the Latissimus Dorsi (lats), connecting the lower back to the arms. Finally, he adds the Deltoids (shoulders) to complete the upper torso.
Summary of the Back Torso Muscles:
- Trapezius (Traps): A large, diamond-shaped muscle covering the upper back and neck. It originates at the base of the skull, runs down the spine, and extends outwards to the shoulder blades and clavicles. It's responsible for the slope from your neck to your shoulders.
- Latissimus Dorsi (Lats): These are the broad, wing-like muscles of the back. They originate from the lower spine and pelvis and sweep up to insert into the upper arm, passing underneath the armpit. In muscular individuals, they create the characteristic "V-taper" of the torso.
Notice how the traps and lats from the back, and the pecs from the front, all converge and connect to the arms via the shoulder (deltoid) muscle. This makes the shoulder a critical junction point that links all the major masses of the upper torso.
Practice Session (15-20 minutes)
It's time to apply this knowledge. Your task is to create anatomical maps on top of the structural underdrawings you practiced in the last lesson.
We will follow the process outlined in the article "How To Draw The Torso: Front View".
How To Draw The Torso: Front View
This article provides a clear, step-by-step guide that perfectly combines our last lesson with this one. We'll be focusing on the initial construction steps.
Read the section 'How To Draw The Torso Step by Step'. We will be focusing on executing Steps 1, 2, and 3.
Your Drawing Exercise:
- Find 2-3 References: Use a site like Line-of-Action.com or SketchDaily.net to find clear, well-lit photos of figures from the front and back.
- Execute Steps 1 & 2: For each reference, lightly sketch the line of action, followed by the simplified 3D forms of the ribcage and pelvis. This is a direct application of last lesson's skills.
- Execute Step 3: Map the Muscles: Now, using your underdrawing as a guide, loosely sketch in the major muscle groups we covered today.
- On your front view, map out the pectorals, abdominals, and the line of the obliques/serratus.
- On your back view, map out the diamond shape of the trapezius and the large V-shape of the lats.
- Goal: The goal is not a finished, rendered drawing. You are creating an anatomical block-in. Your drawing should clearly show the major muscle shapes wrapping around the underlying forms of the ribcage and pelvis.
Conclusion
Excellent work today. You have successfully bridged the gap between the skeletal structure and the visible surface of the human form. By learning to map the major muscle groups, you can now add a new layer of realism and understanding to your figure drawings.
Key Takeaways:
- The contours of the torso are defined by a few major muscle groups wrapping around the ribcage and pelvis.
- Front/Side View: The key players are the Pectorals, Rectus Abdominis, Obliques, and Serratus.
- Back View: The dominant forms are the Trapezius and Latissimus Dorsi.
- The process for drawing the torso is to first establish the underlying bony masses (ribcage, pelvis) and then map the muscle groups on top of that structure.
In our next lesson, we will extend this anatomical study outwards from the torso. We will move on to simplify the major muscle groups of the arms and their primary functions (flexing, extending), learning how they connect to the torso to create a complete upper body.