Yoga is a practice that combines physical postures, breathing exercises, and meditation to achieve physical, mental, and spiritual harmony.
Yoga and Ayurveda are two interrelated branches of the same great tree of Vedic knowledge that encompasses all human life and the entire universe. In this regard, it is important to understand the respective roles of Ayurveda and Yoga in the Vedic system.
In this classical Vedic scheme, Ayurveda is the Vedic system developed specifically for healing purposes. There is no other Vedic system of healing apart from Ayurveda. Yoga is the Vedic system of spiritual practice or sadhana. All Vedic sadhana or spiritual practice involves some form of Yoga practice.
This means that Yoga is not originally or inherently a medical system. It does not address either physical or psychological disease or their treatment in a primary manner. Yoga aims at relieving spiritual suffering, which it defines according to the kleshas or spiritual afflictions starting with ignorance (avidyà) of our true nature as pure consciousness, which leads us to a false identification of ourselves with our transient bodies and minds.
This does not mean that we cannot use aspects of Yoga medically, but that this is not its primary intent or orientation. To do so would require applying Yoga in a different manner than what it was originally meant to be.