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