Along the spine, the chakras are aligned. Except for the first and final chakras, all of the chakras are horizontal. They are linked to one another. Each chakra has many channels along which prana flows. These channels link the chakras together like a network of veins pumping blood through the body. There are several theories about the origin of the chakras. One theory is that they are seven energy centers on the human body where spiritual energy is stored. Another theory is that they are seven parts of the mind and heart where spiritual consciousness is manifested. Still another theory says that they are seven points on a compass where divine power is located. However, no matter how they originated, today they are considered to be the energy centers where vital life forces are stored. The Sanskrit word chakra means "wheel." In Hinduism, Buddhism, and Jainism, these bodies of energy are believed to exist at every level of existence, from the physical world down to the soul level and even beyond. The chakras have been compared to lotus flowers, with each chakra being like a petal; or, like the wheels of a chariot, with each chakra having the same relationship to the next as the hub of a wheel has to its rim.