(par-ee-vrit-tah trik-cone-AHS-anna)
parivrtta = to turn around, revolve
trikona = three angle or triangle
Step-by-Step Instructions

1. Stand in Tadasana. With an exhalation, step or lightly jump your feet 3½ to 4 feet apart. Raise your arms parallel to the floor and reach them actively out to the sides, shoulder blades wide, palms down. Turn your left foot in 45 to 60 degrees to the right and your right foot out to the right 90 degrees. Align the right heel with the left heel. Firm your thighs and turn your right thigh outward, so that the center of the right kneecap is in line with the center of the right ankle.
2. With an exhalation, turn your torso to the right, and square your hip points as much as possible with the front edge of your sticky mat. As you bring the left hip around to the right, resist the head of the left thigh bone back and firmly ground the left heel.
3. With another exhalation, turn your torso further to the right and lean forward over the front leg. Reach your left hand down, either to the floor (inside or outside the foot) or, if the floor is too far away, onto a block positioned against your inner right foot. Allow the left hip to drop slightly toward the floor. You may feel the right hip slip out to the side and lift up toward the shoulder, and the torso hunch over the front leg. To counteract this, press the outer right thigh actively to the left and release the right hip away from the right shoulder. Use your right hand, if necessary, to create these two movements, hooking the thumb into the right hip crease.
4. Beginning students should keep their head in a neutral position, looking straight forward, or turn it to look at the floor. More experienced students can turn the head and gaze up at the top thumb. From the center of the back, between the shoulder blades, press the arms away from the torso. Bring most of your weight to bear on the back heel and the front hand.
5. Stay in this pose anywhere from 30 seconds to one minute. Exhale, release the twist, and bring your torso back to upright with an inhalation. Repeat for the same length of time with the legs reversed, twisting to the left.
6. Watch a demonstration of Revolved Triangle Pose

POSE INFORMATION
Sanskrit Name
Parivrtta Trikonasana
Contraindications and Cautions
Back or spine injury. Perform this pose only with the supervision of an experienced teacher or avoid it altogether.Also avoid this pose if you have:

• Low blood pressure
• Migraine
• Diarrhea
• Headache
• Insomnia

Modifications and Props
One of the most common problems in this pose is the inability to keep the back heel grounded, which makes the pose very unstable. There are various ways to deal with the back heel. First, of course, you can just accept the situation and work diligently to press through the heel (and open the back-leg groin) even though it's off the floor. Second, you can perform the pose with your back heel wedged against a wall, which gives you something to push into. Or finally, you can raise the back heel on a lift and, over time, work to gradually lower the lift until the heel stays on the floor.
Deepen the Pose
When you bring the bottom hand to the outside of the forward leg, press the forearm firmly against the outer shin. This pressure of arm-against-leg will help your torso rotate more deeply into the pose.
Theraputic Applications

• Constipation
• Digestive problems
• Asthma
• Lower backache
• Sciatica

Preparatory Poses

• Baddha Konasana
• Prasarita Padottanasana
• Siddhasana or Sukhasana
• Supta Virasana
• Supta Baddha Konasana
• Uttanasana
• Utthita Parsvottanasana
• Utthita Parsvakonasana
• Utthita Trikonasana
• Virabhadrasana II
• Virasana
• Vrksasana

Follow-up Poses
Parivrtta Trikonasana is usually sequenced just after (as a counterpose to) Trikonasana. You can also use this pose as a standing preparation for seated forward bends like Janu Sirsasana and seated twists like Ardha Matsyendrasana and Marichyasana III.
Beginner's Tip
This pose is slightly easier with a narrower stance. Beginners should also, as suggested in the main description, bring their hand to the inner foot, whether on the floor or on a support like a block or folding chair.
Benefits

• Strengthens and stretches the legs
• Stretches the hips and spine
• Opens the chest to improve breathing
• Relieves mild back pain
• Stimulates the abdominal organs
• Improves sense of balance

Partnering
A partner can help you stabilize and align this position and get a better feel for the twist. Perform steps 1 and 2 in the main description above. Have your partner stand behind you and wrap a strap across your front hip crease. Then continue with the rest of the pose. As you move into the twist, the partner will pull firmly on the ends of the strap, dragging the front groin deeper into the pelvis and the outer front hip away from the shoulder. Also, he can pull in on the strap to help you keep the front hip tucked in and, with one of his feet, press against and ground your back heel.
Variations
Parivrtta Trikonasana leads into a very interesting variation, not usually described in popular instruction manuals, called Parivrtta Ardha Chandrasana (Revolved Half Moon Pose). Perform the pose (twisting to the right). Then exhale, bend the right knee and reach the left hand forward on the floor (or onto a block) about 12 to 18 inches beyond the right foot (with the hand positioned on the big toe side of the foot). Inhale and straighten the right knee, lifting the left foot off the floor and bringing the leg parallel to the floor. Hold for 30 seconds to a minute, return the left foot to the floor with an exhalation, and leave the twist as described in step 5 above. Repeat on the other side.

Source: yogajournal.com