so what we're looking at here is a compact bone model and so all this stuff right here is compact bone like all bone all bone is surrounded by this which is a connective tissue covering a bone and that is known as the periosteum now what connects the periosteum to the bone is you can see these white fibers here so those white fibers that are connecting the periosteum to the bone and those are called perforating fibers or they're also known as sharpies fibers so this is the periosteum here and these are the sharpies or perforating fibers okay we move to the other side of the of the bone this is showing inside of the medullary cavity and so this gray stuff that's lining the cavity that is called the endosteum so that's the endosteum or endosteum however you want to pronounce it so that's a membrane on the inside of the bone so if we look at compact bone you can see that it's made up of these circular structures of bone so you can see there's a hole in the middle and then many rings of bone around that hole that whole structure there or that whole structure there that whole structure there is called an osteon so there's one osteon here's another osteon these are trying to show right here and here osteons projected upwards okay so right down the middle of the osteon is a a canal there a hole and that is called the central canal now if we turn this on the side here this is trying to show central canal here and here and here and here so central canals contain blood vessels and nerves we're not going to ask for blood vessels and nerves so what we'd ask here are canals now there are tubes that connect those canals and that's what we see here and here and there as well and those tubes that also contain blood vessels are called perforating canals are also known as volkman's canals perforating or volkman's canals we come back up here to the top here when we see when you're looking at the osteon here you're seeing these holes spaced here and there and those holes those small cavities are called lacuna so those are called lacuna right there small cavities are called lacuna and also if you're looking at the bone you're seeing these small little lines in the bony material itself and those are called canaliculi so the small little lines that you see all over the place are called canaliculi now osteocytes i'm sorry lacuna house osteocytes so this is a lacuna which isn't just a cavity right here just a cavity if you look over here this model here is trying to represent that lacuna containing an osteocyte so when we show it on these spider-like structures right here and here and here uh that's what we mean by an osteocyte finally osteons are made of concentric circles of bone so each one of these circles not the line but this right here the bony material is called a lamella so this is a lamella this is a lamella this is a lamella this is lamela and so on and over here we're seeing a few lamella that are projected upward so we can see them a little better