It's a relatively common occurrence for newer yoga students to practice Urdhva Mukha Svanasana (upward-facing dog pose) without effectively mobilizing their scapulae. The result is collapsed shoulders that crowd the ears, inefficient thoracic extension, and shearing forces that create stress at the acromio- and sternoclavicular joints. Engaging the lower and middle trapezius muscles to depress and retract the scapulae will elevate the trunk, broaden the collar bones, extend the thoracic spine, open the heart and create a more skillful line of force through the clavicles into the sternum. Check out these great images from Yoga Functional Anatomy, as well as a short video clip on this subject from one of the ASFYT-3 classes!
In the illustrations below you can see the acromioclavicular and sternoclavicular joints, as well as the effect of contracting the lower trapezius. Please note that the asana illustrations are courtesy of Yoga Functional Anatomy - which you should definitely check out if you haven't already!
Video Clip from an ASFYT-3 Class
Got any comments, questions or other great tips about how to work the shoulders in Upward Facing Dog? Please share below!