Muktasana is described in the "Hatha Yoga Pradipika," but it is only mentioned as a different name for siddhasana, or accomplished pose in English. There are many sources with matching descriptions for these two poses. "Gheranda Samhita" and other Hatha yogic sources consider it a unique pose, offering the same effects as siddhasana, but being a little more accessible.
Practicing muktasana calms the entire nervous system by moving the prana from the lower centers up to the spine and stimulating the brain. It improves memory and focus, helps to elliminate the negative thinking and is an ideal pose for practicing meditation.
It is believed to purify the nadis, which are the 72,000 energy channels of the body. Practicing this pose may help in states of anxiety, mild depression or fatigue. It also helps regulates blood pressure.
This pose stimulates the first chakra, the muladhara, which is believed to be the survival center of the body. It also stimulates the sexual energy and benefits the reproductive organs.