Only cardiac muscle has this particular appearance, which is given to it by something called intercalated discs. Cardiac muscle also consists of single muscle cells, called Cardiomyocytes; where something such as skeletal muscle cells are MULTInucleated (more than one cell nucleus).
Cross-section of skeletal muscle in which the complex of proteins and sugars on the cell surface is stained green. The actin in the muscle fibers is shown in red and the cell nuclei are blue. Confocal fluorescence image.