The only way to seriously study anatomy, among other things, is to study the names of the parts that make-up the whole, and this includes anatomy, in order to have an integrated knowledge of the subject matter. I still remember a much of the names of many of the muscles. You definitely do have to know the origin and insertion points of all the muscles to properly understand how they work and relate to one another. If all you know is what you see then in actuality you don't know much at all, you must all always go deeper and look further to have the best possible understanding of the reality in front of you.
You asked about how I practiced to become adept at illustrating anatomy. First thing is to get proper anatomical reference material to study from. Do not study anything on anatomy produced by comic book artists. Study anything a doctor would have had to study to get his license.
-You only have to study one half hour to one hour per day.
-Then without drawing anything look at the material, at each part of the body and how it relates to what's adjacent to it.
-Always take just one part of the body each day and concentrate on studying just that.
-Practice sketching the contours of the body. For instance notice how each side of the arm, or leg etc. compares to the other.
-Then move on to the underlying muscle and bone.
-One of the most important thing you should remember is not just to practice sketching but also probably most important of all is to look, and understand what it is that you are seeing.
Sorry I took so long to reply - been busy. You asked about anatomy books, there are a few good ones. I recommend, for specific reasons that are just too elaborate to get into right now, three books; Artistic Anatomy by Dr. Paul Richer, - the other two I am going to have to get the specific names and titles for you, I actually studied the interiors of the books not the names of the titles and the authors.
The other two books I believe would be very relevant to you are 'Atlas Of Anatomy For Artists' by Fritz Schider, and 'The Male And Female Body In Motion: 60 Classic Photographic Sequences' by Eadweard Muybridge.