This database documents each muscle and its following attributes: its joint, action, insertion and origin points. In order to prevent various integrity violations, I had to denormalize the database(s) I had on the different joints,muscles and its actions. Many of these muscles share the same attributes (i.e joints and actions), therefore there are no unique constraints in the database.
One muscle can have different joints and/or actions; another muscle can find itself with the same attributes as the next. If there was a case of uniqueness constraints, the nature of this database would not allow it and there would pop up constraint violations as more entries are entered into the database.
The UML & RELATIONAL SCHEMA were made prior to the database, these diagrams apply if there was another attribute that could act as a surrogate key -- if there was a factor that made these muscles unique from one another.
BOOK USED: Manual of Structural Kinesiology (12th Edition)