In Ashtanga Vinyasa Yoga, Marichyasana D is one of the core poses or gateway postures of the seated sequence. The Ashtanga practice is organized in a progressive manner, such that whatever asana you practiced will build the proper foundation for whatever asana is coming next in the sequence.
Marichyasana D requires flexibility in three main areas: hips, shoulders and spine.
HIPS. The pose requires a deep external rotation of the hips in order to build Half Lotus Pose. Due to the twisted spine position, a deeper external rotation on the hips will be needed in order to get into the pose without creating too much pressure on the knee joint, especially the inside ligaments. Previous poses like Janu Sirsasana A-C and Marichyasana A-C will work on the flexibility of the hips and shoulders that you will need in Marichyasana D. Feel free to hold these poses for more than 5 breaths.
SHOULDERS. Having enough mobility in the shoulder joints will facilitate the bind and the twisted position of the spine in Marichyasana D. For this twisted pose with half lotus, we will need to take a closer look into the different movements of the arms.
First, we must wrap the binding arm around the binding/bent leg (not the leg in Half Lotus), To do that, shoulder protraction and internal rotation of the arm are required in order to reach the binding arm forward enough to get the elbow beyond the shin bone. Ideally, the armpit should be in contact with the thigh.
Next, as you wrap the arm around the shin bone, work on a deeper internal rotation of the arm, and depress the shoulder. Keeping the arm below the knee joint will avoid the arm from sliding off when you try to bind the hands together. The other arm will work slightly different: extend the arm backwards to open the pectorals muscle (muscle on the chest), then internally rotating the same arm and bring it close to the back, in the direction of the wrapping arm. Once both hands are connected, this shoulder will retract to facilitate the twisted position of the spine.
SPINE. We can identify 3 main sections in the spine: lumbar, thoracic, and cervical. The thoracic spine is the one responsible for twist. Focus in this area as you move into the asana following the instructions described above with regards to shoulder mobility, as this will facilitate the rotation of the spine.
As you hold the pose, you must breathe in the upper ribs area, as the lower ribs will be compromised in the twisted position. Deep breathing will allow the body to relax and settle down in the pose.
If binding is not possible yet, try to stay up to 8-10 breaths in all the Marichyasana poses prior to Marichyasana D; this will not only open the hips, but also work on the internal rotation of the shoulders.
The most important advise that we can give you in this practice is to be patient with your body. Do not force the body to get into the pose. Every time you are in an asana, if the breathing is too restricted or is stopped, it means that you are close to or over your limits. The Ashtanga Practice can expand your limits, however, it requires patience, dedication and,inner connection.
Keep practicing! =)