Let’s start layering on some more terms on the humerus. We are going to add the Deltoid tuberosity and Radial groove. These can be difficult to find on your bone. The Deltoid tuberosity is where the deltoid muscle connects to the humerus. Due to the variety of excercise folks get (or lack of exercise in my case) explains the wide range of prominence of the Deltoid tuberosity. Some are almost non-existent. However, if you know the anterior of your humerus you will know that the only thing your teacher could be pointing to in the middle of the bone is the Deltoid tuberosity. The same thing can be said for the Radial groove on the Posterior side.