Chakras are vortices of activity that receive, assimilate, and express energy in the form of emotions, thoughts, sensations, etc. The word “chakra” is derived from the Sanskrit word for "wheel" or "turning", and refers to a spinning sphere of bio-energetic activity emanating from the major nerve ganglia branching forward from the spinal column. Generally, seven major subtle energetic centers are described, stacked in a column of energy that spans from the base of the spine to the crown of the head.