Applications Myograph Blood pressure measurement Contractile force of cardiac muscles Walking / Gait analysis Catheter – type transducers – Blood pressure

Myograph Force of contracting muscles  attached strain gauge  change in resistance  Wheatstone bridge  change in voltage Strain gauge resistance myograph

Blood Pressure Blood Pressure  motion of stiff diaphragm  strain gauge bonded on diaphragm

Contractile force of cardiac muscles Strain Gauge reistance myograph on excised papillary muscle Strain Gauge Arch  sutured to wall of left / right ventricle In situ means of continuous recording of force developed by cardiac muscle Encapsulated version of S.G permanently implanted on animals

Cardiac strain gauge Can measure prestress of cardiac muscles To investigate diastolic loading (preload) To study the effect of increased stretch to increase the force of contraction (Sterling’s law of heart)

Walking / Gait analysis Miniature strain gauges bonded directly on the bones To measure strain in the bone during walking Requirements – Careful preparation of bone surface – Special adhesives and coverings – Water proof the lead and S.G – Careful dressing of leads Leads brought to skin surface through surgically prepared tunnel

Cather Type Strain Gauge Transducers