all fours position, 1. the sixth stage in the Rood system of ontogenetic motor patterns. In this stage, the lower trunk and lower extremities are brought into a co-contraction pattern while stretching of the trunk and limb girdles develops co-contractions of the trunk flexors and extensors. See Rood System. 2. (in obstetrics) a position in which the body rests on the arms and the knees with the knees held wide to open the pelvis.
