Frequency histograms. All bins are one twentieth of a sarcomere long. (A) The length of each axial tubule expressed as a fraction of the length of the sarcomere. N = 52. Mean = 0.56, median = 0.44, mode = 0.26, SD = 0.31. (B) The length of each axial junction expressed as a fraction of the length of its axial tubule. N = 40. Mean = 0.66, median = 0.73, mode = 1.00, SD = 0.30. (C) The length of each axial junction expressed as a fraction of the length of the sarcomere. N = 40. Mean = 0.30, median = 0.24, mode = 0.19, SD = 0.18.