Re: Do ants have rotator cuff muscles?

Hi Danielle:

Humans, having an internal skeleton, have a different method of muscle attachment than insects. The rotator cuff is a very complicated group of musles and tendons that holds your shoulder together:

from clevelandclinic.org.

Insects, on the other hand, have an external skeleton, and don't have anything analagous to a shoulder – their muscles are attached to the inside of their skeleton, and their joints are hollow (so insects don't have something analogous to a ball and socket joint like we have). I unfortunately couldn't find a good picture of an insect joint – if you ever have the chance to eat a lobster, have a look at the joints, they're pretty similar to those of an insect!

In other words, if we think about a skeleton as a bunch of pipes, humans have their muscles on the outside of the pipes, while insects have their muscles on the inside.

You can find a great overview of skeletal systems and musculature here.

I hope that helps!
Rob Campbell, MAD Scientist