They’re named after their shape. “Rhomboid” comes from their roughly diamond-shaped appearance.

They connect your spine to your shoulder blade. Both help control the scapula.

They help pull your shoulder blades together. That's called scapular retraction.

They help keep your shoulder blade against your rib cage. They're important for controlled shoulder movement.

They work together. Rhomboid minor sits above rhomboid major, and both contribute to scapular retraction and downward rotation.