It was a "Morgul blade" a magic poisoned dagger designed to bring its victim into the realm of the Ring Wraiths, thus making him easier to capture and thus take the One Ring from him.
The Ringwraiths wound Frodo with a Morgul-knife (note that this is not an individual name but a general one).
The shoulder blade is the scapula.
The Nazgul King.
The crack in the shoulder blade is called the Scapula
The Scapular is the medical term used for the shoulder blade.
The shoulder or shoulder blade
Scapula is the bone commonly known as "shoulder blade"Shoulder blade
The breastbone is anteromedial to the shoulder blade.
The scientific name for the shoulder blade is the scapula.
The main function of the shoulder blade is that it is an attachment area for many muscles. Some of the muscles include the Pectoralis Minor, Coracobrachialis, and Serratus Anterior.
Drogo
The ridge on the dorsal surface of the shoulder blade is called the spine.