Define the scapulohumeral rhythm and describe how it relates to arm movement

Question

What will be an ideal response?

Answer 1

The scapulohumeral rhythm is the ratio of movement between the glenohumeral and scapulothoracic joints. In an ideal rhythm, the scapula remains stable until 90 degrees of glenohumeral (GH) joint flexion or 60 degrees of GH joint abduction, then moves in approximately a 1-to-2 ratio with the humerus. An ideal rhythm reflects shoulder girdle stability and muscular balance. Premature scapular motion throws the rhythm off and destabilizes the shoulder girdle, which can lead to muscular imbalances and a faulty movement coordination in the shoulder and arm. Restrictions to scapular motion will also throw the rhythm off and limit GH joint motion.