mesophragma

M line

a fine line in the center of the A band of the sarcomere of striated muscle myofibrils. Synonym(s): M band, mesophragma

mesophragma

(mĕs″ō-frăg′mă) [″ + phragmos, a fencing in] A band in the center of the A band in the myofibrils of a striated muscle.