Isolated skeletal muscle fiber from the Flexor Digitorum Brevis muscle of a normal mouse. Fibers were isolated and attached to laminin-coated coverslips, fixed with 2% paraformaldehyde
and air dried before scanning. The major transverse periodic ridges correspond to the underlying structure called the costamere, a specialized submembrane cytoskeletal complex which overlies
the z-disc of the sarcomere, 20 µm scan.
Image courtesy of D. Milner and S. MacLaren, University of Illinois at Urbana-Champaign.