The Muscles

There are more than 600 muscles in the body, and they fall into three groups—skeletal, smooth, and cardiac. The smooth and cardiac muscles deal primarily with internal organs and are not evident in surface anatomy. Skeletal muscles, on the other hand, make up a large portion of tissue that is next to the skin on an ideal figure, and they play a large part in how the human body looks and moves. Figure 3.4 shows the male figure with many of the important muscle groups shown.

Many of the skeletal muscles of the body are close to the surface and have dramatic influence on how a human form looks. There are also many muscles that are deeper in the body and have little direct visual impact on it. Memorizing all of the muscles might help the artist understand the body, but understanding the main muscles of the body is essential to good figure drawing.

The following is a list of the more important muscles and what they do.

• Sternomastoid. Sternomastoids are the large muscles on the sides of the neck. They are attached to the skull on the top and the clavicle on the bottom. These proponent muscles help to give the neck its distinctive shape.

• Trapezius. The trapezius muscles extend from the shoulder to the spinal column and from the bottom of the skull to about halfway down the back. They are triangular muscles used for raising and lowering the shoulders and also pulling the scapula closer together. In addition, the trapezius muscles contribute to the movement of the neck and head. They are mostly prominent as the large muscles on the back of the shoulder leading from the shoulder to the neck. When highly developed in the male figure, the muscles will have a pronounced bulge.

• Deltoid. The deltoid muscle is one of the most prominent muscles in the body. It forms the outer part of the shoulders. It is attached to the clavicle in the front and the scapula in the back, and also the humerus in the arm. The deltoid muscle is a powerful muscle that is used to raise a person’s arm. If you hold your hand over the deltoid and lift your arm in the air, you can feel the muscle contracting.

• Pectoral. The pectoral muscles are the large, prominent muscles covering the upper ribcage. They form two bulky masses that are most prominent in the male figure. In the female figure, they are somewhat covered by the breasts. A common mistake of beginning figure artists is to focus on the breasts on a female figure and not recognize the underlying muscles beneath them. The pectoral muscles are the primary muscles for moving the arm forward. If you hold your arms straight out in front of you and press your hands together, you can feel the strain on your chest, and you can even see the pectoral muscles bunch.

• Serratus anterior. The serratus anterior is a group of muscles along the outer ribcage that attach to the inside of the scapula. They help to rotate the scapula, and thus the arms, downward. They have a distinctive rib-like appearance in a lean person and are often mistaken for the rib bones themselves.

• External oblique. The external oblique muscles form the fleshy muscles running from the lower ribcage to the upper pelvis on the sides of the torso. They are the muscles responsible for bending the torso from side to side.

• Abdominal. The abdominal muscles are the muscles on the front of the body that attach the ribcage to the front of the pelvis. They are lumpy muscles that are most prominent in a lean, muscular figure. There are six muscles at the top of the abdomen, three on each side, which form what bodybuilders often call a six-pack. Don’t make the mistake of drawing more muscles in the abdomen than are actually there.

• Iliac crest. The iliac crest is not a muscle, but rather the bony area of the pelvis where it is close to the surface. The crest protrudes on a thin or elderly person and is a dimple on a heavy person.

• Sartorius. The sartorius muscle is a long strap-like muscle that extends from the outer pelvis to the inside of the leg, attaching to the upper tibia. It is an important muscle that gives the thigh its distinctive curvature. It is responsible for helping in the rotation of the upper leg.

• Quadricep. The quadricep is made up of four major muscles on the front of the thigh. The vastus medialis is on the inside of the leg and bulges just above the knee. The vastus intermedialis is near the center of the leg. The vastus lateralis is on the outside of the leg and forms the outward bulge of the thigh as seen from the front view. The rectus femoris is the largest of the four muscles and covers much of the central part of the front of the thigh.

• Gastrocnemius. The gastrocnemius, also known as the calf muscle, is the large fleshy muscle on the back of the lower leg. It is muscle we use when we stand on our toes. It pulls the heel up and the foot down.

• Tibialis. The tibialis is on the front of the lower leg and is much smaller than the calf muscle on the back. It is used to pull the heel down and the foot up.

• Bicep. As the name suggests, the bicep is actually two muscles that are used to pull the lower arm up. This is the muscle that is often most associated with a strong, muscular person. Bodybuilders will often flex this muscle to show their arm development. It is one of the most prominent and recognized muscles on the body.

• Tricep. The tricep is three muscles on the back of the arm that pull the lower arm counter to the bicep. They form the massy bulge on the upper part of the back of the arm below the deltoid.

• Brachioradialis. The brachioradialis is just one of the many muscles of the forearms. It is prominent in that it forms a bulge on the outer part of the arm running from between the tricep and bicep and around to the wrist. It is one of the longer forearm muscles.

• Flexor carpi radialis. On the opposite side of the forearm from the brachioradialis is the flexor carpi radialis. This muscle forms the distinctive bulge on the underside of the arm.

Figure 3.5 shows some of the major muscle groups from the back.

Some muscle groups that are better seen in the back view of the figure are as follows:

• Latissimus dorsi. The latissimus dorsi is the largest muscle in the body and gives the back the familiar V shape. They are sometimes referred to as lats for short. They extend from the shoulder to the small of the back and are used to pull the scapula together and the arms back. You use your latissimus dorsi muscles when you do a rowing motion. They attach to the spinal column and form the double ridge of the back on either side of the spine.

• Lumbodorsal fascia. The lumbodorsal fascia are the massive muscles located in the lower back area. They continue the double ridge of the spine down to near the pelvis. They are the muscles used for bending the torso back and lifting.

• Gluteus medius. The bulging muscles of the buttocks are formed on the top by the gluteus medius. These muscles are involved in lifting because they pull the pelvis back in relation to the thigh. They are also used to pull the leg back when walking or running.

• Gluteus maximus. The lower, bulkier part of the buttocks is made of the gluteus maximus muscles. These powerful muscles work in the same way as the gluteus medius muscles in that they pull the leg back in relation to the pelvis. If you hold your hand over the muscle while standing up, you can feel the muscle flex. These muscles are very pronounced and distinctive on the human figure.

• Biceps femoris. Like the bicep in your arm, there is also a bicep in your leg called the biceps femoris muscle. These muscles work to bend the leg at the knee similar to the bicep in the arm. They attach to the lower pelvis and the upper fibula and by ligaments to the tibia.

• Achilles tendon. The Achilles tendon is not a muscle, but rather a tendon. It attaches the gastrocnemius, or calf muscle, to the heel. The Achilles tendon is the most pronounced tendon in the body and serves a very important function. Without them, it would be impossible to stand or walk.

Figure 3.6 shows the female figure with her muscles labeled.

As you can see from the labels, all of the muscles of the male figure are also present in the female figure. However, the size and bulk of the female muscles are very different from the male’s. In almost every case, except for the hip and thigh, the male muscles are more massive and defined.

The female figure naturally has a little more fatty tissue than the male figure. This fatty tissue tends to smooth out some of the muscle definition, causing the female form to look smoother than the male figure.

The female breast is one of the most distinguishing aspects of the female figure. The breasts are made up of fatty material and are not muscles. Because of this, the breasts tend to change shape as the figure moves to different positions.

Figure 3.7 shows the female figure from the back.

From the back the female figure has a distinctive hourglass shape. The more slender the person, the more pronounced the hourglass shape of the figure. Because this shape is considered beautiful by many, women often go to great lengths to maintain a slender figure.

I hope that this explanation of the muscles is helpful in your study of anatomy. As you become more familiar with muscles, you will learn how they react to each other to create motion. You should study how the muscle looks when it is relaxed and how it looks when it is flexed.

Some muscles rotate, such as in the lower arms and legs. These muscles can look very different depending on the extent of the rotation. Take, for example, the forearm. Look at your forearm relaxed. Now rotate the arm to the left without turning the upper arm. See how the muscles change? Now try rotating the arm to the right. Look at the differences in the muscles.

It is insufficient to study the muscles by themselves. The figure artist must also understand how the muscles work together to move the body. Some muscles flex to move the body one way, and others flex to move the body another. You need to understand which muscles do what.

Another element of the human form is that there is a great deal of difference in the figure depending on how much fat the person is carrying on their body. Fat tends to obscure the muscles and bony areas of the body because it often forms a layer between the skin and the muscles. Placement of fat differs greatly in individuals as well. Some people will carry fat high, forming large bellies, while others will carry it low, forming large hips.