It’s a turkey drumstick! Answer to Freak of the Week #7

Tibiotarsus of a turkey

Many of you got this one! It IS a turkey bone and is from the leg, but which bone is it? It’s the tibiotarsus, or long bone of the lower leg. In mammals that bone is known as the tibia, so why is it called the “tibiotarsus” in birds? Well, it’s more than just a tibia. It’s actually a tibia with tarsal (ankle) bones fused into the distal end of the bone. You can see in the photograph that the shape of the distal end of the turkey tibiotarsus resembles the tarsal bone (astragalus) in deer that articulates with the tibia. This fusion of the tibia with the proximal tarsal bones is present in birds and acts to help in absorbing the stress of landing, takeoff, and running.
The tibiotarsus is also what you are holding on to when you’re eating a turkey or chicken drumstick. Many people assume that the drumstick is the femur but it’s actually the lower leg with the calf muscles. So the next time you’re having turkey at a holiday dinner and someone asks you what part of the turkey you want, you can now say “I’ll have the tibiotarsus please”! By the way, the turkey bone in the photos was part of my family’s Thanksgiving dinner in 1981. If you’re a bone nerd like me, you don’t let them go to waste!

It’s also interesting to look at the tibiotarsus of a wild turkey from an archaeological site compared with a modern commercially-raised turkey (photo). Wild turkeys and domestic turkeys are all the same species (Meleagris gallopavo) but modern commercially-raised turkeys are bred to be almost twice the weight of their wild counterparts. They grow fast and abnormally large, and sometimes can have crippling leg abnormalities.

Posted December 2, 2013

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