Parivrtta means revolved, turned round or back. Trikona is a triangle. This is the revolving triangle posture. It is a counter pose to Uttihita Triknasana.
This asana tones the thigh, calf and hamstring muscles. The spine and muscles of the back are also made to function properly, as the pose increases the blood supply round the lower part of the spinal region. The chest is expanded fully. The pose relieves pains in the back, invigorates the abdominal organs and strengthens the hip muscles.
This is the twist. All twists relieve backache, headache, and stiff necks and shoulders. They improve spinal flexibility and open the hips. They also stimulate the digestion by massaging the internal organs.
This asana improves the functioning of kidneys and strengthens the thigh muscles.
Note: Please perform the yoga under the guide of a certified yoga teacher especially for beginner. You are at your own risk and responsible if you perform on your own. Whatever provided here is just act as an information.
Source from Light on Yoga by B.K.S. Iyengar
Ashtanga Yoga for Women by Sally Griffyn & Michaela Clarke