This is the result of caries of the anterior portion of the body of the vertebrae, which allows the vertebrae to come nearer together in front, thus prying the spinal processes apart and producing an unnatural prominence. The disease makes its appearance the most frequently between the ages of four and twelve years. It is indicated by unnatural squareness of the shoulders, stiffness in walking, pain produced on slight jarring, slight tilting backward of the head, unnatural separation of the feet in standing, pains in the stomach or bowels, generally about the navel, and difficulty in bending the trunk in the morning. Upon examination of the spine there will be found in some part of it an unnatural prominence. When the vertebrae of the neck are affected, the head is usually thrown back, the breathing is short and irregular, and often accompanied by a slight sigh or grunt. The patient is also much troubled with hiccough. When the disease is located in the lower part of the back, pain often runs around the pelvis and down the legs. Sometimes there is contraction of some of the muscles of the thigh, in consequence of which one or both limbs may be drawn up. In this case, the patient is generally hollow-backed when standing upon the feet, the spine being turned forward.