When an infant is held up by the feet in an inverted position definite attempts to adjust to the unusual situation can be observed. The features which characterize the adjustment exhibit regular sequential change as age advances. The situation is simple and the response is relatively uncomplicated; probably for this reason it has been unusually informative in reflecting maturation of the neuromuscular mechanism.
The present study of postural adjustment to an inverted position has been made in a group of 77 children over a period of approximately five years. Observations were made at weekly or less frequent intervals; the total number of observations was 2,841. Of these 1,382 were recorded on motion picture film, and 1,459 consisted of written protocols. Approximately 7,500 feet of film were exposed in making the records. In addition to the data for the group, daily records (four or five days a week) were obtained on
McGRAW MB. NEUROMUSCULAR MECHANISM OF THE INFANTDEVELOPMENT REFLECTED BY POSTURAL ADJUSTMENTS TO AN INVERTED POSITION. Am J Dis Child. 1940;60(5):1031–1042. doi:10.1001/archpedi.1940.02000050015003