This can be compared to the body of Lord Shiva, who in mythology is described as half male (right) and half female (left). The left side toe faces North and heel is towards South. Ladies are dominantly influenced by the Southern premises. It is also figuratively described that the Holi Ganges has its origin at the feet of The Lord and flows from His toes. This approximates to NorthEast.
All scriptures proclaim that not a blade of grass moves without His will and He lives in every living beings. All the universe is in Him. All life (plant, animal & bird life even) all prompted by Him only. Vastu science helps in manifestation of HIS BEING. Home/Place of any family closely reflects the nature and activity of that family. Even with the awareness of this science, one may not able to detect the vastu defects. These defects would be corrected only in accordance with HIS WILL.