A chakra is a vortex of energy within your body. It’s an energy center and each energy center within the body is believed to hold spiritual power. The term, chakra, comes from the Sanskrit word that means "wheel" and is used within the yoga tradition, in meditation circles and in Ayurvedic medicine. The entire chakra system can be used as an incredible source of healing.
There are seven chakras within the chakra system, and each one has a different physical, psychological, emotional and spiritual significance. The seven chakras run from the base of the spine to the crown of the head. They’re all aligned with each other. They’re also all connected. That’s why imbalances in one chakra can create an imbalance in another. Likewise, when a chakra is balanced, the other chakras can more easily follow suit.
Each of the seven chakras corresponds with nerve centers within the body. Each chakra has within it nerves as well as actual organs. The chakras hold both physical matter and non-physical consciousness. As such, they are major sources of physical, mental, emotional and spiritual power.
Because chakras hold such power, we want to make sure that they remain both open and balanced, so that our life force energy, or prana, can move freely and fluidly through them. It’s no easy task to keep chakras totally healthy and balanced, which is why we practice yoga asana, meditate and visualize whole-body healing. (Learn more in What's the Importance of Prana?)
There are tons of guided meditations out there that help you balance your chakras. Practically all yoga poses help do this, too. Books have been written on the subject as well if you want to delve into your own chakra studies. The chakra system is indelibly intriguing. If you want to learn more about your chakras, I encourage you to check out books by Anodea Judith, one of the foremost chakra experts in the West. (Read more in The Chakras and Maslow's Hierarchy of Needs.)