The placing reaction in adult neurology.

The first description of the placing reaction (PR) in 12 human adult cases is given. The optimum position for eliciting the placing reaction (PR) is the dangling leg posture, i.e. the same as for the forward groping of the foot. There are three forms of PR quite similar to those noticed in animal physiology, i.e. the visual-PR, the dorsum-PR and the sole-PR. The term contact placing is preferred for the last two forms. The PR is encountered only in patients displaying a forward and medial groping of the foot as well as a groping of the hand on the same side. The PR is usually ipsilateral to the main cerebral lesion but there was no single case with a well limited unilateral lesion. An involvement of retrorolandic areas seems to be necessary for the occurrence of PR. It is concluded that both groping phenomena and the PR are highly coordinated reflexes subserving self-preservation and belonging to antigravity mechanisms, i.e. the standing posture.