(1) Normally, the superior and inferior vertebral epiphyses appear at about eleven and one-half years of age.

(2) Any gross deviation from the time at which these epiphyses appear, any deviation from their order of appearance, the presence of tenderness and abnormal X-ray findings are pathologic.

(3) The pathologic changes seen in the roentgenogram are as follows: The epiphyses become enlarged, moth eaten, frayed, and indistinct; the intervertebral spaces become cloudy, mottled, and irregular; the vertebral outlines become indistinct; all of these parts then tend to fuse into one indistinguishable mass. This is followed by the stage of regression in which the process is reversed.

(4) These abnormalities are found in a disease entity, occurring between the ages of ten and twenty-one and characterized by sensations of fatigue, backache, tenderness of epiphyses, and characteristic roentgenographic appearances.

(5) Many of these cases develop deformities of the spine.

(6) Deformities of the spine due to known causes do not present the above findings.

(7) The etiology is unknown. There is evidence leading to the belief that it is a very low grade infection in the spine.

(8) Stress and strain constitute additional factors which aid in the production of deformity.

(9) The condition is analogous to Legg's disease, Osgood-Schlatter's disease, Koehler's disease, and similar conditions, and forms part of a greater entity: Multiple Epiphysitis of Adolescence.

In closing, I wish to thank Dr. Royal Whitman and Dr. Percy W. Roberts and their respective staffs for the use of their material and their co-operation. I am deeply indebted to Dr. Samuel Kleinberg, who has patiently guided me, advised me, and constructively criticized me. I am grateful to Mr. Joseph Flick, the Superintendent of the Hospital, for extending to me the use of the X-ray Laboratory for the study of normal spines.