In personal injury cases, the defense attorney is allowed to hire a doctor to examine the plaintiff and offer medical opinions at trial.
Much like the doctors hired by the tobacco industry that routinely find that smoking is harmless, these “defense doctors” are routinely hired by the same defense firms and insurance companies, and routinely find that the plaintiff was not injured. In the cases where the doctors cannot deny that the plaintiff was injured (for example a large disc herniation can be clearly seen on an MRI film), these defense doctors always find a way to blame the injury on any event other than the event for which the lawsuit was filed.
Personal injury attorney Howard Kapp wrote an interesting article on how to prevent these doctors from using the pretext of a medical exam to subject the plaintiff to second deposition in which the doctor goes fishing for ways to bolster the defense’s case.