Elbow work is using the forearm or the point of the elbow for slow, deep pressure over large muscles.
The tool is broader than a thumb and smaller than a palm, so a quadriceps, a glute, or a back can be met without the practitioner's hands fatiguing into a jab. In 📝Deep Tissue Massage the elbow is a slow instrument, not a sharper one. Speed with an elbow is how the work becomes bruising. The method is a contact choice, not a diagnosis, and not a claim that more bony leverage equals better work.
Clients feel a specific, spreading weight. If they cannot breathe, the contact is too much or too fast. Bony edges, the front of the neck, and fresh injury are not elbow surfaces.