Bodymechanic,
As you are probably aware, there are many different chiropractic techniques that use various forms of diagnostic means to inspect, detect and correct a subluxation. Many utilize a surface EMG scan called MyoVision or the Insight station. Gonstead technician utilize a G0-scope. Many upper cervical DC utilize an thermography. CBP utilizes X-rays to address postural issues, NUCCA utilizes specific X-ray analysis for addressing their line of correction down to cm for adjusting atlas only. Activator methods which is performed with a spring loaded instrument is another means.
You can utilize one or many of these as well as techniques such as muscle testing, motion palpation, and/or leg checks.
Chiro's are trained to treat a specific segment as opposed to segmental area.
I hope that may help. Again, I don't think the manipulation is the issue, I believe it is the difference of paradigms in treating and keeping patients healthy. A lot of DO's have been too quick to quick to rely on the "reliable information"
fed to them from big pharma than rely on the amazing powers of the human body to heal and restore itself from thier manipulations.