Abnormal Z disk morphology Increased Z-disc width 2020-05-14T08:36:59Z Increased Z-disk width Abnormally increased width of the Z-disk of the sarcomere, resulting from splitting or opening of the Z-disc (c.f., Figure 2 of PMID:28732005). The sarcomere is the basic contractile unit of striated muscle, and is composed of highly ordered thin (actin) filaments and thick (myosin) filaments. The cytoskeleton surrounding this elegant contractile molecular machinery is required as a scaffold to ensure efficiency of contraction. Longitudinally, sarcomeres are connected by Z-disk lattices that anchor thin filaments and transmit force along the myofibril. The strikingly regular lateral alignment of Z-disks between adjacent myofibrils ensures that during contraction myofibrils change length in unison, thus preventing damage to membrane systems that span between myofibrils and that are responsible for activating and relaxing the sarcomeres (T-tubules, sarcoplasmic reticulum). Widened z-discs