T is for Tendon
When I was in college, I was a student instructor for a physics lab. Our physics department had two separate physics tracks: one for engineers and students in the physical sciences, and one for students in the life sciences, many of whom were pre-med. The lab I taught was part of the second track.
Every week, all of the student instructors taught the same lab to a dozen different sections of students. At the beginning of the week, we'd all meet to go over the lab, ourselves, to make sure we understood what we were teaching and how to use the equipment.
One week, we were doing a lab which involved holding a bowling ball and estimating the amount of force being exerted on one's tendon. In order to get an accurate estimate, we had to hold our arms at a right angle and measure the angle of the tendon. One of us held the ball, and a couple of us pulled out rulers to estimate the points of attachment, at which point, we ran into a problem.
None of us knew which one was the tendon.
"Is that the tendon? Or is that a ligament?" "I think that's a muscle." "So where's the tendon?" "Maybe it's a sinew. . . ."
Here we were, a half-dozen physics students, completely baffled by our own elbows, and not sure what to do about it.
Suddenly, I had a thought.
"Guys! At least half our students are pre-med — they'll know which one is the tendon!"
Satisfied, we worked out a general equation with the tendon values left as variables and finished the lab. Sure enough, when it came time for me to teach the lab, my students came to the rescue and got to give me a lecture, for once.
(Ironically, when lab day arrived, it turned out we were missing another key piece of information, namely, the weight of the bowling ball. We'd been provided with scales, but they only measured up to 2500 g, and the balls didn't have their weight printed on them. Happily, yet another student saved the day. He was an avid bowler, so he knew what each standard bowling ball weight felt like to carry. We just handed him each ball, in turn, and he told us what it weighed. Good times.)