However, I've had a look at both professions and hopefully will provide a more thorough explanation...
What do we study...?
Both chiropractors and osteopaths undergo a 4 or 5 yr degree course at University and study all the basic biomedical sciences (anatomy, physiology, biochemistry, pathology, biomechanics, nutrition, pharmacology etc), together with the hands-on clinical stuff (physical examination, orthopaedics, neurology) and the various different treatment techniques (manipulation, mobilisation, soft tissue work, rehabilitation etc.) Students have to complete 2-3 years in the teaching clinic (real patients with real problems under supervision from clinicians) and complete a clinical research dissertation prior to graduating. On graduating, many of the associations require completion of a year-long Pre-Registration Training Scheme before they can be fully registered.
There are several different Universities and Colleges in the UK that offer chiropractic or osteopathy, as well as those elsewhere in the world. All courses and colleges should be accredited with the appropriate educational and regulatory body.
How are we regulated...?
Both professions are regulated and protected in the UK by the General Chiropractic Council (GCC) or General Osteopathic Council (GOsC) respectively, who set and maintain the Code of Practice and Standards of Proficiency. Both regulatory bodies require all practitioners to register with them, and it is illegal to call yourself an osteopath or chiropractor, or to practise as one, if you are not on the appropriate Register. The GCC and GOsC require renewal of registration on an annual basis, and will check to see that the applicant has met the mandatory Continuing Professional Development (CPD) requirements, is in good health and good character, is in a 'fit state' to practise and has appropriate indemnity insurance. They can and do prosecute bad people, strike them off the register, or put restrictions of practise on them!
In addition to this, individuals may join an association (eg the British Chiropractic Association, British Osteopathic Association). Each different association has its own membership criteria, (some more stringent than others, so may be a useful indicator in the 'quality' of the practitioner). The associations provide a number of different services and support for the practitioner, for instance indemnity insurance, business and clinical advice and legal support.
The College of Chiropractors is another body; subdivided into regional and educational faculties, its primary role is the provision of postgraduate education, courses and seminars. Attendance at these can be used not only to meet the annual CPD requirements, but also to gain further post-graduate qualifications.
So, what do we actually do...?
Both chiropractors and osteopaths specialise in the diagnosis, treatment and management of conditions that affect the neuromusculoskeletal system and the affect that these may have on the overall health and wellbeing of the whole body. Both chiropractors and osteopaths use 'hands on' techniques (including manipulation, adjustment, mobilisation, soft tissue work, fascial release techniques, myofascial dry needling) to mobilise joints, ease muscle tension, reduce pain and restore neurological function. Most chiropractors and osteopaths will advise on rehabilitative exercises and stretches, posture and ergonomics, diet, nutrition and general exercise and lifestyle in order to promote recovery, prevent recurrence and improve overall health and wellbeing of the patient.
Whilst traditionally thought of as just working on the spine (admittedly, we do tend to specialise in this!) both chiropractors and osteopaths treat the whole body. Hence, as well as treating problems affecting the neck, and low back pain we are proficient at treating problems affecting all the joints (including hip and knee pain, shoulder and elbow injuries, sports injuries, repetitive strain and over-use problems).
Does it work and is it safe...?
By taking a thorough medical and case history, and performing an extensive physical assessment, chiropractors and osteopaths are trained to pick up problems or complications that might prevent, or interfere with treatment. If this is the case, they are able to refer you on to the appropriate specialist, usually via your GP. The most appropriate type of treatment will be used for each individual patient, and techniques can be modified and adapted as necessary, so are safe and effective for people of all ages, shapes and sizes.
The efficacy of chiropractic or osteopathy is supported in a number of peer-reviewed research studies, (particularly when assessing manipulation in the management of chronic or acute, low back or neck pain), but as in all areas of medicine we need more research!
And, finally, which one's best...?!
Both chiropractic and osteopathy are safe and effective in the management of problems with the muscles, joints and nerves. Both require a long period of initial and continued training, both are stringently regulated. As in any profession, regrettably there are unscrupulous individuals, and some practitioners may be better or worse than others. When advising whom to see, I always recommend that people should ensure that the practitioner is registered with their regulatory body, and ideally go with a 'word of mouth' recommendation from someone who has been a patient there before. At the end of the day, the appropriate qualified professional, whether chiropractor or osteopath, should be able to provide safe, professional, responsible and ethical care of patients.