If we understand FORM we can understand FUNCTION and consequently MOVEMENT and DYSFUNCTION. Understanding origins and insertions isn’t just for A&P class in college. Traditionally the rhomboids and serratus anterior were viewed as individual muscles and separate entities that affected the scapulco-thoracic joint.
However understanding the role of fascia and the connectedness it plays throughout the entire body gives us the knowledge that muscles aren’t separate compartmentalized entities. The rhomboids tie into the serratus anterior which wrap around into the internal oblique rectus abdominus and eventually the external oblique. One continuous sheet of muscles all connected as Thomas Myers labels the spiral line.
Dysfunction in one area will alter function in another. Over dominant rhomboids will inhibit serratus function. This is one reason we like to pair our spiral line work together. Every rhomboid dominant pull is combined with a serratus dominant push movement to get the stabilizers on each side working effectively with each other.