Each pose has it’s own personality in a way. Not every yoga pose has total joy or completely open breath, some have difficulties that are not immediately recognizable. Trikonasana or “triangle pose” starts out well-grounded, one foot pointing toward the short edge of the mat, the other about three or four feet away with toes pointing toward the long edge of your yoga mat. From this grounding, a familiar one for yoga practicioner’s, think Warrior II with both legs straight, the pose then extends (and this is a good word to keep in mind) laterally out reach your hand out further than your front foot (the one pointing to the short edge of your mat) keeping the torso long and straight - practice against a wall, lead hand reaching toward your ankle and the other arm floats up fingers reaching toward the sky. It’s a very two dimensional pose, thus the wall as support is great for finding the real balance of the pose, shoulderblades will be touching the wall.
This side bending is difficult for some, but can also be found in simpler poses such as Parighasana (aka Gate pose) and others that highlight the latisimus dorsi. The trick, or place where the real work begins is the focus on the extension of the crown from the hips so that the spine is running parallel with the floor. Feeling that wonderful extension of the spine in this pose makes it feel so open and wonderful. The placement of the hand, inside the foot, outside, on the ankle or shin, is all up to you and your practice - each particular yoga school of thought has their own ideas and one teacher may differ from the next, the key is to go with what works for you. Your teacher should be your guide and understand the slight variations your body or mind may need.
Enjoy Your Yoga!
