Lesions of the soft moving parts are extremely common. They cause recurrent pain and disablement and constitute the most important avoidable cause of industrial absenteeism and of compensation for injury. Sooner or later, everyone suffers from articular sprain or degeneration, from strain of muscle tendon or ligament, from inflammation of joint capsule or bursa. Attacks of displacement within the joints of the spine are all but universal, with consequent painful compression of dura mater or root sleeve. Cases of orthopaedic medical trouble are responsible for a fifth of all attendances to a family practitioner. They call for accurate diagnosis and equally precise treatment, far more often by conservative means as distinct from surgery. Grasp of the principles of orthopaedic medicine enables the interested doctor or consultant to single out the tissue at fault quickly, even in cases where radiography is uninformative or positively misleading. Foremost among these conditions are intervertebral disc lesions -- real and alleged -- the scourge of man since he achieved the upright posture and now of the law courts as well. The eighth edition is presented in a new format using a larger page and bolder headings. The double column layout allows better positioning of the illustrations in relation to their relevant text.