Help on Anatomy Exam

idkmybffjill · Jan 23, 2018

I had a similar test in my A&P class. I just figured out which bone markings were on the anterior or posterior and what were more lateral or medial. If you can tell the scapula you are looking at is the anterior side because of the markings, then you can look at those marking to figure out which part is medial and which is lateral. From there, you can tell which side it's on in general. I doubt your professor will make it too hard, as they probably won't be upside down or turned weirdly.

The only issue I had with this was with the clavicle, since for me it was difficult to make out the markings without being able to move it around, so I can't really help with that one. I was lucky that my professor apparently took the lazy route and I noticed she took all the pictures from the textbook, which used only bones from the right side.

lotus_37 · Jan 24, 2018

Hi! Thanks so much for answering. Forgive me if this sounds incredibly dumb, but how exactly does knowing which side is lateral or medial help me determine the direction of it? I feel like this would help for example with the tibia and fibula, where the bones are different, but for example with the hip bone (coxal), how would knowing that the acetabulum faces laterally help me determine if the image i'm looking at is right or left?

idkmybffjill · Jan 24, 2018

Because the coxal bones are also different from each other, as they are mirror images and thus will have one acetablulum facing the right and one facing the left. If you are able to figure out what's anterior/posterior and what's lateral/medial together, you can orient the bone to a body because a left coxal bone won't work on the right side. I usually try to visualize the bone lining up with my body personally.

For instance, if you look at the two pictures that are hopefully going to attach to this post. In both, you can tell from the shape, that the pubis is more anterior compared to the ischium. The pubis is at the front/anterior of the body, so we can figure out that these are anterior views. As you pointed out, the acetabulum will be lateral. So, for the first picture, for the bone to be seen from the anterior view and the acetablulum to be lateral, it must be the left coxal bone. If you were to try to place that first bone on the right side, there's no way that the acetabulum could be lateral and the bone be facing forward as, with the anterior in that direction, the acetabulum faces toward the left (in perspective of the person) even if you slide it over to the right side. For the second picture, you use the same idea. Anterior view. The lateral acetablulum, unlike the first bone, is facing toward the right from the person's pov. If you orient it to the whole body, it can only be a right bone.

If it helps, you can stand up and line your body in the same way as the pictures. Visualize how the picture would line up with your own body. If you face away from the screen so you are in the same position as the image, could that first picture be on your right side with the acetablulum being lateral? Or does it fit on the left instead?

Hopefully this makes sense. I think it's easier to explain in person.

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lotus_37 · Jan 24, 2018

Thank you so much for taking the time to explain this concept to me. It helped me understand it a lot better and I definitely feel more confident about my exam now.

Thanks again! :)