The two points at which the Moon's path intersects the ecliptic are called the ascending and descending nodes. They are analogous with the March and September equinox points where the ecliptic similarly intersects the celestial equator. Ptolemy refers to the lunar nodes in a discussion of bodily injuries and diseases in Tetrabiblos III.12: [translate Robbins p. 325 lines 17ff beginning with "Again"]. In other words, if the new or full moon -- especially at an eclipse or square to the nodal axis or in one of the five signs mentioned -- "bears upon" angular Mars or Saturn, or vice versa, then various body deformation results. Some astrologers treat the Moon's nodes in much the same manner as if they were physical bodies, i.e., similar to planets.