myographs

A myograph is an instrument used to measure the mechanical activity of muscle tissue. In laboratory physiology and pharmacology, it is commonly used to quantify the force, tension, or length change produced by an isolated muscle or a ring of vessel tissue within a controlled bath of physiological solution. Myographs support several modes of operation, the most common being isometric, where muscle length is held constant while force is recorded, and configurations tailored to small vessels, such as wire or pressure myographs that monitor changes in tension or diameter under controlled conditions.

Typical components include a bath chamber with temperature and chemical composition control, a mounting system for the tissue (hooks or fine wires), a force transducer or sensor, and a data acquisition system. Some systems use micromanipulators to adjust tissue length; others maintain intraluminal pressure for vascular studies. Specimens commonly studied include skeletal muscle strips, cardiac trabeculae, smooth muscle segments, and small arteries.

Applications span cardiovascular pharmacology, smooth muscle physiology, and drug testing, as well as basic muscle physiology research. Myographic data are used to construct length-tension relationships, study active and passive properties, and generate dose–response curves for pharmacological agents. The term can sometimes be confused with electromyography, which records electrical activity rather than mechanical contraction.