Astanga Yoga

According to Dr. Suraj Mirashi Ashtanga yoga is a system of yoga recorded by the sage Vamana Rishi in the Yoga Korunta, an ancient manuscript "said to contain lists of many different groupings of asanas, as well as highly original teachings on vinyasa, drishti, bandhas, mudras, and philosophy"

As told by the Sage Patanjali Ashtanga Yoga means “eight-limbed yoga”. For internal purification to reveal the Universal Self one has to follow the following eight spiritual practices

Yama [moral codes]
Niyama [self-purification and study]
Asana [posture]
Pranayama [breath control]
Pratyahara [sense control]
Dharana [concentration]
Dhyana [meditation]
Samadhi [contemplation]

For the correct performance of Asanas in Astanga Yoga, Vinyasa and Tristhana must be incorporated.

"Vinyasa means breathing and movement system. For each movement, there is one breath.For example, in Surya Namskar there are nine vinyasas. The first vinyasa is inhaling while raising your arms over your head, and putting your hands together; the second is exhaling while bending forward, placing your hands next to your feet, etc. In this way all asanas are assigned a certain number of vinyasa.

Tristhana refers to the union of "three places of attention or action: posture, breathing system and looking place. These three are very important for yoga practice, and cover three levels of purification: the body, nervous system and mind. They are always performed in conjunction with each other".