Skeletal muscle Skeletal muscle Skeletal muscle is one of three major muscle types, the others being cardiac muscle and smooth muscle. It is a form of striated muscle tissue, which is under the voluntary control of the somatic nervous system. Most skeletal muscles are attached to bones by bundles of collagen fibers known as tendons. A skeletal muscle refers to multiple bundles (fascicles) of cells joined together called muscle fibers. The fibres and muscles are surrounded by connective tissue layers called fasciae. Muscle fibres, or muscle cells, are formed from the fusion of developmental myoblasts in a process known as myogenesis. Muscle
Skeletal muscle "flexor" and "extensor"; "abductor" and "adductor"; "levator" and "depressor"; "supinator" and "pronator"; "sphincter", "tensor", and "rotator" muscles. A flexor muscle decreases the anterior angle at a joint; an extensor increases the anterior angle at a joint. An abductor moves a bone away from the midline; an adductor moves a bone closer to the midline. A levator raises a structure; a depressor moves a structure down. A supinator turns the palm of the hand up; a pronator turns the palm down. A sphincter decreases the size of an opening; a tensor tenses a body part; a rotator turns a bone around