「The endomysium, meaning within the muscle, is a wispy layer of areolar connective tissue （疎性結合組織）that ensheaths each individual myocyte (muscle fiber, or muscle cell). It also contains capillaries （毛細血管）and nerves. It overlies the muscle fiber's cell membrane: the sarcolemma（筋線維鞘; 筋繊維膜; 筋鞘）. Endomysium is the deepest and smallest component of connective tissue.
The term cardiac skeleton is sometimes considered synonymous with endomysium in the heart, but cardiac skeleton also refers to the combination of the endomysium and perimysium.（筋周膜）
This thin layer provides the correct chemical environment for the exchange of calcium, sodium, and potassium. The exchange of these ions leads to the excitation of the muscle fiber.
Endomysium combines with perimysium and epimysium to create the collagen fibers of tendons, providing the tissue connection between muscles and bones by indirect attachment.
The elastic fiber of collagen is the major protein that composes connective tissues like endomysium. Endomysium has been shown to contain mainly type I and type III collagen components, and type IV and type V in very minor amounts. Anti-endomysial antibodies (EMA) are present in celiac disease. They do not cause any direct symptoms to muscles, but detection of EMA is useful in the diagnosis of the disease.」