 This weekend lab, you will be going over the microscopic anatomy of the bone, specifically of compact bone. You'll also be classifying bones by their shape, and then you'll identify the structures of a typical long bone, as well as reviewing the bones of the axial skeleton. So today I want to review a few of the shapes with you and help you with identifying structures of the long bone. So here we have some examples of the various bone shapes. So bones can be classified by their shape. And here we have what we call a long bone, and that's kind of obvious, it's a long bone, this is a humorous bone. And then we also have what we call a round bone. And the round bones are also called sesamoid. They are typically found inside of a tendon. So this would be the patellar bone, and it is found inside the quadriceps tendon. If you know your quadriceps are your muscles of your upper leg. So this is going to be a round bone or a sesamoid bone. We also have several bones in the body that are just simply irregular shaped. So you can tell by this vertebra that it is definitely an irregular shape. It's certainly not a long bone and it's not a round bone. So we would call this shape irregular. And then some of the bones are actually short bones. So you see how these bones here do not have this long shaft in the middle the way that the long bones have that shaft in the middle. So these would be called short bones. And you'll learn that those are the bones of the wrist or the carpal bones. But notice how the bones of the hand do have that middle long piece. So all of these would be long bones and these would be short bones. Then we have another shape called a flat bone. So several bones of the skull, for instance, this rib bone are actually flat. So those are the ways that we can classify the bones by shape. So make sure you look at those in lab this week. So the parts of a long bone, I want to go over with you. As I indicated before, obviously this is a long bone that has this shaft in the middle of it. And then it has the two end pieces. Those are the parts we're going to name. So this shaft is called the diaphysis. Diaphysis. And then the two end pieces are called the epiphyses. Remember epi, epi, I mean sitting upon. So these are epiphyses. So you have two of these. You have what would be considered the distal epiphysis. And then what would be considered the proximal epiphysis. So you can see how the distal epiphysis would articulate with the following bone after that. This is the distal epiphysis. But the proximal epiphysis would go into the preceding bone. In this case, the hip bone. So make sure you know those parts of the long bone. Also in the epiphyses, this bone is filled in with what is called cancelous bone or spongy bone. So you can see how it's porous looking. Looks very much like a sponge. And then you see in the diaphysis, it's made mostly up of a bone that's very, very compact. You don't see any air or anything there in that compact bone. But it is lined, this middle cavity of our bones is also lined with spongy bone as well. So this is again the diaphysis. But notice how there's a cavity in the middle of this bone. This is called the medullary cavity or the marrow cavity. And it does hold yellow marrow in the middle. So you can call it the marrow cavity. You see up here on the ends where you have the spongy bone. This is where the red marrow would be. And red marrow produces blood cells. So as the bone is growing, once the bone has completely filled in, you will see as an adult where a line will form between the epiphysis and the primary diaphysis. And this is called the epiphyseal line. Now as development of a long bone occurs, this is actually cartilage. And at that point it's called the epiphyseal plate. And you understand that because we call it the growth plate. But it fills in with bone eventually in your early 20s. And we refer to it now as the epiphyseal line. So make sure you know all of the primary parts of the long bone.