I agree Beccy about learning structure of body. that is why I study spinal alignment too as it's related to massage work in terms of posture and connected to muscles relationship. however, i dont' see a point in learning about the heart, lungs, kidneys, and all the other organs and anatomy stuff in such detail. unless doing organ stomach massage. all one need is to know the general location for them. we work on muscles directly and those affecting structure of posture indirectly such as spine. yes, i study nerves too since it affects muscle pain. however, i wouldn't go into depth with the non related system such as the central nervous system. automatic nervous system or the enteric nervous system. I will study the somatic nervous system as it is about connection between the nerves and muscles.
the point is you don't need to go into depth like the medical doctors. might as well become a doctor than. for some areas, it's not necessary to be an encyclopedia. we don't have the time to learn everything that we aren't going to use frequently. it's all about efficiency. you may know things. yes. makes you feel good you know it. but are you going to apply it? it's probably go back into the brain for storage from lack of use. for example, I'm taking cpr class right now. is it useful to know the whole anatomy body parts and how they work? no it isn't. cpr class teaches you a skill. knowing those anatomy stuff in depth won't help you do better cpr. sure you feel good knowing it but your never going to use it. they teach anatomy general wise for location but not in depth. the point is to learn materials for purpose of the intended service so you save time. another example is the muscles of the face. if you never do facial massages or work on the head area, there is no point of you learning them muscles in great depth. most likely you'll learn the related jaw muscles due to tmj clients. that's about it.
it really is a question of how much depth should i study for such and such? some things you just don't need to go into as deep unless you specialize in it.