Looking back at studies

Along with the watercolours in my previous post I've found some drawings I completed a few years ago now. I find them useful to hang on to for reference and sometimes inspiration. I try not to throw old work away, unless it really needs to be for good of everyone.
These come from a huge range of studies I did of the heart, from both observation drawings and from my own photographs. I was trying to not only improve my own drawing and observation skills but my knowledge of the heart as an organ. I think that's what really sparked off my interest in the workings of the human anatomy.