Texts describing the chakras go back as far as the later Upanishads, for example the Yoga
Kundalini Upanishad.
Definitions
Although there are various interpretations as to what exactly a
chakra is, the following features are common in all systems:
Paramhans Swami Maheshwarananda
describes a chakra as:[4]
...[a] powerhouse in the way it generates and stores energy,
with the energy from cosmos pulled in more strongly at these
points. The main nadis, Ida,
Pingala and Shushumna (sympathetic, parasympathetic, and central nervous system) run along the
spinal column in a curved path and cross one another several times.
At the points of intersection they form strong energy centers known
as chakras. In the human body there are three types of energy
centers. The lower or animal chakras are located in the region
between the toes and the pelvic region indicating our evolutionary
origins in the animal kingdom. The human chakras lie along the
spinal column. Finally, the higher or divine Chakras are found
between the top of the spine and the crown of the head.
Anodea Judith (1996: p. 5)
provides a modern interpretation of the chakras:
A chakra is believed to be a center of activity that receives,
assimilates, and expresses life force energy. The word
chakra literally translates as wheel or
disk and refers to a spinning sphere of bioenergetic
activity emanating from the major nerve ganglia branching forward from the
spinal
column. Generally, six of these wheels are described,
stacked in a column of energy that spans from the base of the spine
to the middle of the forehead, the seventh lying beyond the
physical world. It is the six major chakras that correlate with
basic states of consciousness...
Susan Shumsky (2003, p. 24)
states a similar idea:
Each chakra in your spinal column is believed to influence or
even govern bodily functions near its region of the spine. Because
autopsies do not reveal chakras, most people think they are a fancy
of fertile imagination. Yet their existence is well documented in the
traditions of the Far East...