Spiral Bound: asana lab
In a handstand, the shoulder externally rotates, taking with it the scapula. In a mature handstand, the scapular upward rotation and protraction within the scapulohumeral rhythm works in dynamic opposition to the thorax. The thorax wants to follow the spiral action and extend [into a backbend], but resisting this creates stability.
The shoulder [humeral aspect of the glenohumeral joint] also externally rotates in backbending. This external rotation is key anytime the Upper Limb flexes to elevate the humerus (reaching forward or out and up overhead) and relates to the preservation of the subacromial space. In counterpoint, the extension of the shoulder (such as Prasarita Padottanasana C as pictured below) is often initiated through internal rotation of the humeral head [and all its attendant tissues throughout the scapulothoracic region and beyond].
I offer more detailed coverage of the internal and external rotations of the appendages and how these translate through the trunk in these formats:
- My book, Spiral Bound
- Anatomy for Yoga workshops and courses at my home studio in Edinburgh (see below)
For more about my book, Spiral Bound: biotensegrity for yoga, check out this page at Handspring Publishing.