The frequency of the so-called scoliosis or lateral curvature of the spine has its principal origin in the position in which the children sit during their school time especially while writing.
But what now is the normal posture? The upper part of the body is to be kept straight, the vertebral column neither twisted to the right nor to the left; the shoulder-blades both of the same height, are, together with the upper arm, freely suspended on the ribs, and in no way supporting the body; both elbows on a level with each other and almost perpendicular under the shoulder-joint without any support; only the hands and part of the forearms resting on the table; the weight of the head freely balanced on the vertebral column and not on any account bent forward, but only turned so much round its horizontal axis, that the face is inclined sufficiently to prevent the angle at which the eye is fixed on the book from being too pointed.
(Dr. R. Leibrich, Consulting Ophthalmic Surgeon to St. Thomas' Hospital.)
The twisted and curved position of the spine caused by writing is doubtless a very potent factor in the production of Lateral Curvature. The more slanting the writing the worse the position, and I would strongly advise that upright writing be universally substituted for the slanting (p. 73).
The posture necessitated by ordinary writing is probably that which causes more harm to the spine than any other, but the system of upright writing so ably advocated by Mr. Jackson is calculated to reduce this harm to a minimum. I have referred to this subject in another part of this volume but I take this opportunity of advising the reader to obtain Mr. Jackson's publications upon this system of upright writing with which I have become acquainted only since urging the advantages of substituting upright for slanting writing in the Second Edition of this book.
(Curvatures of the Spine by Noble Smith, F.R.C.S. Ed., L.R.C.P. Lond., &c. Third Edition, pp. 73 and 108.)