Hatha yoga comes from the Sanskrit word ‘Ha’ means ‘prana’, ‘tha’ represents ‘mind’. Hatha yoga aims to bring about a state of harmony between the pranic & mental forces through its practices.
Hatha yoga is a style of yogic practice wherein the emphasis is on the practice of Asanas (postures), Pranayamas (specialized breathing techniques), Shatkarmas (cleansing techniques), Mudras (symbols) & Bandhas (seals or locks).
The aim of this approach is to bring about a state of detoxification and rejuvenation of Annamaya, Pranamaya koshas, which would help us to get into higher practices of Dhyana (meditation) & Samadhi (contemplation).
The higher practices in turn would help us to get to the other planes namely Manomaya & Vijnanamaya koshas promoting harmony and leading to Anandamaya state of being.
Hatha yoga practice does not lay emphasis on yama & nimayas, which would be practiced once the hatha yogic practices are perfected.
Ashtanga yoga is nothing but eight limbed yoga, originally proposed by Patanjali maharishi.
The eight steps mentioned are:
Yama (moral codes)
Niyama (self code of conduct)
Pranayama (breath control)
Pratyahara (sense control)
Yama, Niyama, Asana & Pranayama are considered to be the external practices which help to bring about a state of perfect synchrony of all the organs, organ systems & functions of the body and also cleanse or purify the physical system of its toxins. These four limbs are also considered to be part of Bahiranga yoga and address Annamaya, Pranamaya & partially Manomaya koshas.
Pratyahara, Dharana, Dhyana & Samadhi are considered as internal practices which help to fetch a state of harmony of our higher functions at Manomaya & Vijnanamaya koshas leading to our true nature which is Anandamaya.