Immunohistochemical labeling of serial cross-sections of anterior latissimus dorsi muscle: 9 days (A–D), and 30 days (E–H) posthatch. In each series, the first image (A or E) is from a serial section adjacent to the cross-section from which the subsequent three images (B–D or F–H) are taken. In the first image (A or E), laminin is red and myosin green. In subsequent images, laminin is deep blue and nuclei are light blue (B–D or F–H), Pax7 is red (C or G), and Pax3 is green (D or H). Several intrafusal fibers clustered within a spindle capsule are near the center of each image, and are smaller in diameter than the larger extrafusal fibers that are always situated outside of the capsule. Open/large arrows indicate intrafusal fibers; small arrows show satellite cells; small arrows with line show a satellite cell expressing Pax3; asterisk, capsule of muscle spindle; e, extrafusal fiber. The same representative intrafusal fibers, extrafusal fibers, and satellite cell nuclei are labeled in each image throughout each series (A–D, E–H). Bar = 30 μm.