ALFRED PASIEKA / SCIENCE PHOTO LIBRARY ALFRED PASIEKA / SCIENCE PHOTO LIBRARY
Shoulder muscles. Computer artwork showing the muscular system of the shoulder, neck and upper back. These are the superficial skeletal muscles. Skeletal, or voluntary, muscles are under direct conscious control. When contracted or relaxed they pull on tendons, which are attached to the bones, causing movement.
Model release not required. Property release not required.