Width of the junctional gap of the triad of various sarcomere lengths in frog skeletal muscle.

The width of the junctional gap between the cytoplasmic leaflets of the transverse tubule (TT) and the terminal cisterna (TC) of the sarcoplasmic reticulum (SR) was measured at various sarcomere lengths (SL). In spite of extreme stretching, when the overlap of thick and thin filaments was lost, the width of the junctional gap remained constant.