If the psoas major frontal plane open-chain action is abduction of the thigh at the hip joint, the closed-chain action is depression of the pelvis.
Supraspinatus Cannot Abduct The Arm
The supraspinatus is an important muscle of the rotator cuff group that is often involved in shoulder impingement syndrome. But for the purpose of this blog article, it is an excellent case study in understanding how joint action terminology can lead students and therapists alike to misunderstand the function of a muscle.
