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149290.  Tue Feb 20, 2007 8:07 am Reply with quote

Q: Why does an octopus have bad table manners?

A: Because it eats with its elbows

When it’s eating, an octopus is able to create “humanlike joints” to bring food to its mouth.

Although an octopus’s arms have infinite degrees of freedom (they can roll, turn left and right, tilt etc), they prefer to use their muscles to create temporary quasi-articulated joints like elbows.

“Researchers recorded muscle activity in octopus limbs, and found that an arm generates two waves of muscle contractions that propagate toward each other. When the waves collide, they form a part-time joint.
This process occurs three times, forming a shoulder where the arm meets the body, a wrist where the suckers have grasped their food, and an "elbow" somewhere in between. The elbow typically exhibits the most movement during food retrieval.”

Human arms are three-jointed and have only 7 degrees of freedom, while your shoulders and wrists have 3 degrees of freedom.

The elbow, meanwhile, has can only tilt up and down giving it one degree of freedom.

Stephen: So can you know tell me:

Q: “What is the main cause of tennis elbow?”

F: Tennis/Sport

A: Work

According to these chaps, more people get tennis elbow from “carpentry work, pulling files or doing factory jobs”.

While tennis is one activity that can cause pain, "most tennis elbow I see is not related to playing tennis," says Dr. Mooar. In fact, most people get it from work rather than play. People can get tennis elbow from carpentry work, from pulling files or from doing factory jobs, according to Robert Sallis, M.D., assistant program director of the family medicine residency program at Kaiser Permanente Medical Center in Fontana, California. Other possible causes include stripping wallpaper, painting or working in the garden.

Tennis Elbow
Octopus elbows

149306.  Tue Feb 20, 2007 8:42 am Reply with quote

Also Etiquette.


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