skeletal muscle, which exists throughout the body The body’s collective muscle tissue constitutes its muscle mass. However, in most contexts, the term “muscle mass” specifically refers to skeletal muscle. This is the only type of muscle that a person can voluntarily control.
Skeletal muscle is a fascinating tissue with a complex structure. It consists of elongated multinuclear cells called the myocytes (or myofibers). The muscle cells can be anything from 1 mm to 30 cm in length. The longest muscle cell in our bodies can be found in the sartorius muscle and is 30 cm (nearly 12 inches!) long. From biology-forums.com
There are around 640 skeletal muscles within the typical human body. Almost every muscle constitutes one part of a pair of identical bilateral muscles, found on both sides, resulting in approximately 320 pairs of muscles, as presented in this article.