The Eight Limbs 

Patañjali set out the eight limbs of Ashtanga Yoga in the Yoga Sūtras.

They are:

yama                       absentions          

niyama                    observances

āsana                      posture

prāṇāyāma          breath control

pratyāhāra           withdrawal of the senses

dhāraṇā                 concentration

dhyāna                   meditation          

samādhi                 Self-knowledge

The yamas (the first limb) are: ahiṁsā (non-violence), satya (truthfulness), asteya (non-stealing), brahmacarya (celibacy) and aparigraha (non-possessiveness).

The niyamas (the second limb) are: śauca (cleanliness), santośa (contentment), tapaḥ (self-discipline), svādhyāya (self-study) and iśvarapraṇidhāna (devotion to God).

In Ashtanga Yoga we generally start by practising the third and fourth limbs (posture and breath control). Over time a dedicated practitioner will also begin to practise the first and second limbs. With the continued practice of the first four limbs, the final four limbs arise naturally, eventually taking the practitioner to the ultimate goal of samādhi.