Albion

Best wishes for a complication-free and successful op, Mr Terrier!

Bubba

DT-glad to see you back, you weren't posting as much for awhile. Hope all goes well with the op.

Bubba

Ergaster

It'll take some research to check out the facial muscle question, although I haven't heard of any major (i.e. quantitative) differences. Although apparently (according to a recent research article) the detailed anatomy of the chimp is not as well documented as people generally assume it is.

However, in some regions it is very well-known, relative to humans. Skeletally there is no difference, of course, but there is some difference in musculature. Chimps and gorillas possess two upper arm muscles that humans do not have: the atlanto-clavicularis and the pectoralis abdominis. The former raises the clavicle, and the latter is an arm flexor. They possess the dorsoepitrochlearis, a tensor of the lower arm fascia (humans have this, in an extremely rudimentary form. Add it to your list of vestiges. ) Humans have a well-developed flexor pollicis longus (flexor of the thumb), not surprisingly, which is a non- or -poorly-functioning rudiment in great apes.

In the lower limb, great apes often possess scansorius and iliotrochantericus, two small hip and thigh muscles. The gluteus maximus in apes has two different parts: gluteus maximus proprius and ischiofemoralis.

Chimps also have a long abductor muscle of the big toe which humans do not (and who is surprised by this?). (Abductors move limbs and other extremities away from the body).

One of the last sane

If it runs between the atlas and the clavicle, is that strictly "upper arm"? Where is the arm considered to end, to an anatomist?

RufusAtticus

DT,

<a href="http://www.bushorchimp.com/" target="_blank">Exhibit A</a>

Ergaster

Okay, so it's not *strictly* upper arm, but from a functional standpoint, it is involved in raising the arm up in the air (the clavicle is attached to the scapula which is attached to the humerus etc.), so it is a functional part of the upper arm. Makes sense, really, when you consider how proportionally big and heavy great ape upper arms are (compared to those of humans).

That's the difference, I guess, between a clinical and a functional anatomist. Us latter are more concerned with what things do, along with where things are.

One of the last sane

Fair enough.
Does this also mean they pack a mean shoulder shrug?

pangloss

Yes - i was given a book published in the 1970's on the emotional lives of primates. The time of the publication is most influential on its contents - in coparing huamn and chimp expressions of emotion, the author displayed photos of a chimp next to photos of Nixon displaying the same expressions...

So, yes, chimps certainly can smile, frown, grimace, etc....

Skydancer

Nixon could smile? The frowns and grimaces I remember....

pz

<a href="http://www.bushorchimp.com/" target="_blank">It must be something about Republicans.</a>