Biological skeletal system monitoring

1. A method of monitoring target tissue of a biological skeletal system including surrounding tissues and skin, the method comprising:

applying a mechanical excitation to a portion of the biological skeletal system using a frequency controlled electromechanical shaker placed in contact with the portion of the biological skeletal system to generate a mechanical wave that passes through the target tissue, the target tissue modulating the mechanical wave to produce a response of the target tissue to the mechanical wave, the response comprising a movement of bone within the target tissue as a solid body;

measuring the response of the target tissue to the mechanical excitation using sensors that are sampled at a plurality of locations distributed across the biological skeletal system, the measuring comprising measuring one or more of acceleration, displacement and velocity of the movement of the bone; and

determining structural or functional status of the target tissue from the measured response by comparing the measured response with a standard indicative of the structural or functional status of the target tissue.

2. The method of claim 1 in which the target tissue is a vertebral column.

3. The method of claim 1 in which the measured response is measured with one or more sensors through skin overlying the target tissue.

4. The method of claim 1 in which the mechanical excitation includes frequencies in the range from 0 to 2000 Hz.

5. The method of claim 1 further comprising measuring the mechanical excitation applied to the portion of the biological excitation system to generate an input signal measurement, processing the measured response of the target tissue by comparing the measured response to the input signal measurement and determining structural or functional status of the target tissue from the measured response after comparison with the input signal measurement.

6. The method of claim 1 in which determining a property of the target tissue from the measurement comprises comparing the measurement to a previously measured response to identify structural and/or functional changes in the skeletal system.

7. The method of claim 1 in which the target tissue comprises one or more vertebra.

8. A system for monitoring the condition of target tissue of a biological skeletal system, the target tissue comprising vertebra and surrounding tissue, the system comprising:

a frequency controlled electromechanical shaker having a movement inducing output for applying a mechanical excitation to a portion of the biological skeletal system to generate a mechanical wave that is capable of passing through the target tissue and being modulated by the target tissue to produce a response of the target tissue to the mechanical wave, the response comprising a movement of bone within the tar et tissue as a solid body;

plural sensors adapted to be distributed at a plurality of locations on the biological skeletal system including the surrounding tissues and skin for sensing the response by measuring one or more of acceleration, displacement and velocity of the movement of the bone; and

a processing system connected to receive output of the one or more sensors and produce a representation of the response.

9. The system of claim 8 in which the processing system is adapted to sample the sensors simultaneously.

10. The system of claim 8 in which the plural sensors are adapted to be located on, or affixed to, a vertebral column.

11. The system of claim 8 in which the plural sensors are adapted to sense the response through skin overlying the target tissue.

12. The system of claim 8 in which the mechanical excitation includes frequencies in the range from 0 to 2000 Hz.

13. The system of claim 8 further comprising a sensor of the mechanical excitation prior to the modulation of the mechanical wave by the portion of the biological skeletal system, surrounding tissues and skin, the processing system being responsive to signals from the sensor and to determine a property of the target tissue from the response after processing of the response by comparing the response to the signals from the sensor.

14. The system of claim 8 in which the processing system is configured to determine a property of the target tissue from the response.

15. The system of claim 14 in which the processing system is configured to determine the property of the target tissue from the response by comparing the response to a previously measured response to identify structural changes in the skeletal system.

16. The system of claim 8 in which the one or more sensors comprise an ultrasound sensor.

17. The method of claim 1 in which the anchored frequency controlled electromechanical shaker applies a mechanical excitation in user defined bursts of excitation having a controlled length, frequency content and repetition.

18. The method of claim 17 in which the bursts of excitation each last at least one second.

19. The method of claim 18 in which the bursts of excitation each last at least 10 seconds.

20. The method of claim 1 in which the sensors comprise an ultrasound sensor.

21. The method of claim 20 further comprising measuring displacement of the target tissue using the ultrasound sensor.

22. The method of claim 21 in which the biological skeletal system comprises one or more vertebra.

23. The method of claim 1 in which the frequency controlled electromechanical shaker is anchored to a rigid body.

24. The method of claim 1 in which the sensors are sampled at a plurality of locations distributed across respective bones jointed by joints of the biological skeletal system.

25. The system of claim 8 in which the frequency controlled electromechanical shaker is anchored to a rigid body.

26. The system of claim 8 in which the sensors are sampled at a plurality of locations distributed across respective bones jointed by joints of the biological skeletal system.