The shoulder blade is a triangular shaped bone. It sits like an inverted triangle with the point aimed toward the floor. It’s one of the major bones that make up the shoulder joint. The medical term for the shoulder blade is the “scapula”. You can feel that bone on yourself. You can actually feel a ridge of bone that runs near the top of the shoulder. That ridge is called the spine of the scapula. The ridge separates two major muscles of the shoulder. The one that sits below the spine is called the infra-spinatus (infra meaning below) muscle. The infraspintaus is one of the four muscles that makes up the rotator cuff.