BED POSTURE AS AN ETIOLOGICAL FACTOR IN 
SPINAL CURVATURE. 
BY 
G. W. FITZ, M.D., 
ASSISTANT-PROFESSOR OF PHYSIOLOGY AND HYGIENE, AND MEDICAL VISITOR, 
HARVARD UNIVERSITY. 
From the Transactions of the 
AMERICAN ORTHOPEDIC ASSOCIATION. 
1898. BED POSTURE AS AN ETIOLOGICAL FACTOR IN 
SPINAL CURVATURE.1 
By G. W. FITZ, M.D., 
CAMBRIDGE. 
The problem of the influence of bed posture in the production 
of spinal curvature has attracted my attention for a number of 
years, and I have taken photographs of cases in which a complete 
history of habit of sleep upon one side was obtained. These cases 
represent both side postures, and resemble one another so closely 
that the accompanying photographs may be considered typical. 
The first figure shows the curve as seen when the patient is stand- 
1 Based on studies mkde in the cqrvailtte |TIj>iio\)f Sqgton Children’s Hospital. 2 
G. w. FITZ 
ing; the second, when in the habitual sleeping posture; and the 
third, when in the reversed position. 
The curves are explained by the fact that the hips and shoul- 
ders are the broadest parts of the trunk and support the ends of 
the spine, leaving the middle portion suspended between them. 
The head also, unless a pillow of sufficient thickness is used to keep 
it in line, tends to slope down toward the mattress and assists in 
their formation. 
The period of sleep is one-half to one-third of the growing time 
of the child, and, consequently, the pressures and strains of an 
habitual sleeping posture have an opportunity to influence the 
growth of the vertebrae and ligaments and shape them in accord- 
ance with their relative positions in the curve. 
The cases studied show marked rotation, and although we cannot 
attribute such rotation to the sleeping posture, yet it is doubtless 
true that any asymmetry of the vertebrae caused by unequal growth 
in the habitual sleeping posture will lead, in standing and sitting 
positions, to complex stresses upon the various bones and ligaments, 
and will result in increased curvature with rotation. 
In the eight cases in which a complete history of habitual bed 
positions was obtained, the fundamental curves correspond to the 
curves produced in the normal individual with a flexible spine 
when lying upon the corresponding side, but modified by rotation. 
In no case with such a history have I found a curve not thoroughly 
consistent with this etiology. 
Histories of bed postures are, however, difficult to get, since 
parents are usually ignorant of the sleeping positions of their chil- 
dren. I am convinced that if we could ascertain them for all cur- 
vature cases, a considerable number would be explained in this way. 
Furthermore, it is not improbable that habitual postures at school 
and at home are more or less determined by the shapes of the verte- 
brae and the lengths of the supporting ligaments, and are manifes- 
tations of attempts at easy attitudes necessitated by such faulty 
bones and ligaments. 
Summary. 
1. Lateral bed postures curve the spine. 
2. Habitual lateral bed postures, by favoring the growth of the 
spine on one side and retarding it on the other, tend to fix such a BED POSTURE A FACTOR IN SPINAL CURVATURE. 
3 
curve by establishing physical changes in the bones and liga- 
ments. 
3. The time in bed is so large a part of the growing period tha 
the distortion may become pronounced. 
4. Inequality in the vertebrse and the supporting ligaments 
brings about asymmetrical strains in standing and sitting postures, 
resulting in increased curvature with rotation. 
5. Bed posture thus becomes an important factor not only in the 
etiology of curvature but in its treatment.