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  • Hello, my name is Stan Prokopenko, welcome to another episode of Proko. In the previous

  • episode, we learned the anatomical structure of Pecs. Now, let’s take a look at how you

  • can apply all this information to construct the forms of the pecs in your drawings.

  • The pecs make a flat front plane that faces slightly upwards. The bottom plane starts

  • at or just below the nipple. The depth of this bottom plane determines how thick the

  • muscle is.

  • Alright, let’s do a drawing of the pecs. I’ll start with a light layin of the skeleton

  • to help me place the muscle on top.

  • Let’s start with the clavicular portion. Originating from the clavicle and stretches

  • the farthest of the 3 portions, until it’s covered by the deltoid.

  • Then the sternal portion, from the entire length of the sternum, converges toward the

  • armpit and dips under the clavicular portion.

  • The lateral border curves up toward the arm. There might even be a double curve when the

  • arm is abducted away from the body, because of how the sternal and abdominal sections

  • overlap and attach to the tendon, as you can see here. When the arm raises the muscle mass

  • keeps its thickness near the armpit where it attaches to the tendon. More of the stretching

  • happens here, closer to the sternum. The tendon from the sternal section can extend an inch

  • or two from the armpit and when a muscular figure flexes, it often creates a dimple,

  • as the muscle fibers take a sharp turn inward.

  • The lower border of the pecs lines up with the bottom of the sternum. According to Loomis,

  • the nipples are roughly one head measurement down from the chin, so the bottom of the pecs

  • are just below that. It’s straight and horizontal, maybe leaning a bit down laterally. When drawing

  • a torso that’s tilted toward you or away from you, this lower border acts as a natural

  • cross-contour line. Use it to show the round form of the rib cage!

  • In male figures, there’s a crescent-shaped fat pad on the lower outer corner that contributes

  • to its boxy-ness. Man boobs are simply a result of that crescent-shaped fat pad gaining more

  • and more mass and running over onto the rib cage. When the arm is raised, the lower mass

  • of the pec thins, and the lower border becomes harder to distinguish. You might see ribs

  • you couldn’t see before.

  • In the next episode, well explore the female chest, and how it’s different and similar

  • to the male chest.

  • Variation (Premium Ad)

  • There are variations to the chest depending on the physique of the person, such as lean,

  • average, muscular, and heavy. To learn more about these variations, head on over to the

  • proko.com/anatomy. The premium section has longer lessons, 3d models, and additional

  • demonstrations. Just sayin’. It’s proko.com/anatomy.

  • Assignment

  • Your homework is a two-parter. For part 1, do a tracing over a model photo of the pectoralis

  • major and all of its bundles. If youre not sure how to do a tracing, refer back to

  • theHow to do an Anatomy Tracinglesson. For part 2 of the assignment, invent the pectoralis

  • major on top of photos of Skelly. I’ve provided reference photos for part 1 and 2 in the link

  • below. Download those and start drawing! If you have the Skelly app, you can create your

  • own pose and draw the pecs on top. Post your work in our anatomy group at proko.com/groups!

  • Credits

  • Thanks for watching everybody! Do the chest-bump-worthy thing and share this video with your friends,

  • give me a thumbs up and comment below. And if you want all the Proko news, look no further

  • than the Proko newsletter! Alright, see you next time!

Hello, my name is Stan Prokopenko, welcome to another episode of Proko. In the previous

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