Anatomy of the Hand

[Radrook]

Being a classical guitarist I am made constantly aware of just how important the hand is in making us human. Coupled with our superior brain it makes possible all motions needed in order to manipulate instruments such as pencils and pens, tweezers, or quick dexterous assembling of mechanical parts of machines which we conceive. Without the thumb and we become unable to manipulate our external world as we have done. Below is a short summary of how the hand is put together.

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Ligaments of the back of the hand

Hand Ligaments are tough bands of fibrous tissue that join bones together. Six major ligaments give stability to the wrist by joining the radius to the carpal bones and binding the two rows of carpal bones together. These ligaments joint with others to link the wrist to the hand.

Joint Capsule
Other stabilizers in the hand include joint capsules, which are made of fibrous connective tissue that surrounds the joints. A synovial membrane inside the joint capsules provides synovial fluid to lubricate all the joints.

Hand Nerves
The median, radial and ulnar nerves are the three major nerves that run the length of the arm through the wrist and down into the hand. These nerves contract specific muscles and gives us sensations of touch, and to feel hot, cold, and pain.
Anatomy of Hand & Wrist: Bones, Muscles, Tendons, Nerves, Pictures

 

[Jimmy D]

Did humans becoming bipedal play a part in our hands developing differently?

 

[FrumiousBandersnatch]

Did humans becoming bipedal play a part in our hands developing differently?

I guess opposable thumbs are no particular hindrance to knuckle-walking, but bipedalism frees the hands for carrying and throwing, so I suspect bipedalism would select for refinements in the shoulders and wrists as much as the hands.

I'm guessing here...

 

[USincognito]

Not bad for a modified fish fin.

 

[Jimmy D]

I guess opposable thumbs are no particular hindrance to knuckle-walking, but bipedalism frees the hands for carrying and throwing, so I suspect bipedalism would select for refinements in the shoulders and wrists as much as the hands.

I'm guessing here...

Makes sense.

 

[AlexDTX]

Or it was designed by God from the beginning.

 

[Jimmy D]

Or it was designed by God from the beginning.

He even left a few working prototypes lying around.....

 

[The Barbarian]

Primitive hominins, but not other apes like chimpanzees, are capable of a power grip and precision three-point chuck grip.

The grips of the chimpanzee differ profoundly from those of humans (Napier, 1960). For suspension from horizontal supports, chimpanzees use a ‘hook grip’ of the four flexed fingers (Napier, 1960; Marzke & Wullstein, 1996). With vertical supports, a diagonal hook grip is used (Susman, 1979; Marzke et al. 1992). The thumb may touch the support, but does not squeeze it against the palm. Chimpanzees use this grip when flailing with sticks, but when the arm swings forward the hand tends to lose its grip, possibly due to weakness of the thumb and its inability to overlap the index finger (Marzke et al. 1992; Marzke & Wullstein, 1996). Because the thumb is weak and short, its distal phalanx is relatively immobile and its distal pad cannot be opposed to those of the fingers, it cannot generate a firm pinch or squeeze.

His analysis showed that the human hand is adapted for gripping spheres and cylinders (Fig. 3).


Fig. 3
During its evolution, the human hand gained two unique grips, first identified by Napier. He called them the precision grip and the power grip and depicted them by the grip of a sphere (top left) and a cylinder (bottom left) (Napier, 1956, 1965, 1993 ...
In Napier's description of the precision grip (Napier, 1956, 1965, 1993), the terminal pad of the thumb forms one jaw of a clamp, the other being formed by the fingertip pads. Large objects held in this way involve all the fingers, but smaller ones require only the thumb, index and middle fingers with the fourth and fifth fingers providing lateral stability. Marzke (1983) refers to this as the ‘three-jaw chuck’ grip, depicts the grip of a baseball, and notes that if the object is thrown, the fingers contribute to aim, propulsion and velocity. According to Napier, in the power grip the clamp around the cylinder is formed by the partly flexed fingers and the palm, counter pressure being applied by the thumb, which is wrapped over the dorsum of the fingers, where it acts as a buttress to reinforce the grip. Marzke (1992a) calls this the ‘finger-active palm squeeze’ grip, illustrates it with a hammer and states that it employs all the fingers to secure a cylindrical tool against the palm, so that the tool functions as an extension of the hand and forearm.

These descriptions make it clear that the ‘precision grip’ is a throwing grip, and the ‘power grip’ is a clubbing grip. ‘Precision’ and ‘power’ suggest typical uses for the grips. ‘Three-jaw chuck’ and ‘finger-active palm squeeze’ refer to the position of the hand when it forms the grips. They could be called the ‘sphere grip’ and ‘cylinder grip’ based on the shape they are best able to grasp. The terms throwing grip and clubbing grip emphasize the evolutionary context in which these grips evolved by specifying the behaviours that account for them. The unique features of the human hand can be viewed as adaptations for throwing and clubbing.
Evolution of the human hand: the role of throwing and clubbing

Notice that the chimps retain the primitive ape hand, but human hands are strongly evolved for tool use. Turns out, Australopithecine hands are more like those of humans, but are transitional between those of other apes and of humans.

 

[FrumiousBandersnatch]

Primitive hominins, but not other apes like chimpanzees, are capable of a power grip and precision three-point chuck grip.
...
Notice that the chimps retain the primitive ape hand, but human hands are strongly evolved for tool use. Turns out, Australopithecine hands are more like those of humans, but are transitional between those of other apes and of humans.

I remember seeing quite an interesting analysis that the human hand and the front of the human skull are better adapted than would be expected by chance to... fist-fighting.

Whether there is any anthropological evidence for fist-fighting being a common form of settling disputes or competing for mates though history, I don't know (I can't think of any outside of the gypsy/traveller/Roma lifestyle). I do know that when untutored fighters go at it they swing in a way that is unlikely to cause serious harm and tend not to use straight punches, so that may count against the idea.

 

[Radrook]

Or it was designed by God from the beginning.

Here is an article in harmony with that view.
Human Hand Capabilities Impossible to Duplicate | The Institute for Creation Research

 

[The Barbarian]

I remember seeing quite an interesting analysis that the human hand and the front of the human skull are better adapted than would be expected by chance to... fist-fighting.

Whether there is any anthropological evidence for fist-fighting being a common form of settling disputes or competing for mates though history, I don't know (I can't think of any outside of the gypsy/traveller/Roma lifestyle). I do know that when untutored fighters go at it they swing in a way that is unlikely to cause serious harm and tend not to use straight punches, so that may count against the idea.

Ah, the "boxer's fracture." Roundhouse swing, grazing hit, and the smallest metacarpal fractures. My youngest son had an um... disagreement with a fellow student once. Came home with his hand the size of a small melon.

Took him to our orthopod (all my kids played soccer, so we were on a first-name basis). He comes back with the X-rays and says "who won?"

Then he explained how to avoid doing it again, if he ever need to punch out someone.

Today, we help describe the similarities and differences between two interesting creatures: arthropods and orthopods. Let’s begin!
http://gomerblog.com/2016/02/the-difference-between-an-arthropod-and-an-orthopod/

 

[JackRT]

IIRC some cultures never developed fists as a weapon.

 

[The Barbarian]

Or it was designed by God from the beginning.

If God designed it, there wouldn't be any flaws...

I spent about 9 years doing ergonomics work for an insurance company. Most of the time I was dealing with the consequences of the re-orientation of bones and tendons, which in human hands, tend to entrap and compress the median nerve, sometimes to the point of total disability in the hand.

If the median nerve was routed a different way, there's be no such problems. But it was routed though the carpal tunnel in other mammals, and so there we are.

Surgery doesn't have such a good record; I was able to reduce the frequency of this by a number of job redesigns, but a combination of wrist bending, frequency of motion, and force pretty much guarantees that a significant number of people will develop symptoms.

 

[Jimmy D]

Here is an article in harmony with that view.
Human Hand Capabilities Impossible to Duplicate | The Institute for Creation Research

That article is poor even by their standards.

 

[Radrook]

If God designed it, there wouldn't be any flaws...



If God designed it, there wouldn't be any flaws...

I didn't know that atheism and Catholicism are compatible. I assumed that they are mutually exclusive.

 

[TagliatelliMonster]

I didn't know that atheism and Catholicism are compatible. I assumed that they are mutually exclusive.

Catholicism doesn't have issues with mainstream biology, unlike some other denominations.
Surely you know this. So I can only wonder why you pretend not to know it.

 

[OldWiseGuy]

If God designed it, there wouldn't be any flaws...

I spent about 9 years doing ergonomics work for an insurance company. Most of the time I was dealing with the consequences of the re-orientation of bones and tendons, which in human hands, tend to entrap and compress the median nerve, sometimes to the point of total disability in the hand.

If the median nerve was routed a different way, there's be no such problems. But it was routed though the carpal tunnel in other mammals, and so there we are.

Surgery doesn't have such a good record; I was able to reduce the frequency of this by a number of job redesigns, but a combination of wrist bending, frequency of motion, and force pretty much guarantees that a significant number of people will develop symptoms.

Carpal tunnel is a symptom of unnatural repetitive motion, never intended by God in the design of hand and wrist. Most of our physical problems are caused by misuse of our bodies.

 

[Radrook]

The only time I suffered a hand problem was when I went to Church and made the mistake of shaking hands with this harmless-looking small senor citizen brother in the faith who was rumored to have superhuman strength. It was like placing me hand in a veritable vice.

"What's wrong brother?" he calmly asked as I sat there speechless from the agony.

"Is my handshake too BRISK? " he said while tightening the vice on the word "Brisk!".
I subsequently suffered from pain in my hand, had to go get it x-rayed and it took months for it to finally subside. I even considered a lawsuit for malicious infliction of damage but felt sheepish going to court considered how deceivingly frail and inoffensive the brother looked.

I was later informed that instead of saying "Excuse me!" when a hefty sister was in his way in church he would just effortlessly lift and place her to one side despite her outweighing him by maybe 200 pounds.

WEIRD!

BTW
He has since passed away. So I guess his hand-crunching days are over.

 

[JackRT]

Hope he didn't try the handshake stunt with St Peter.

 

[Radrook]

Hope he didn't try the handshake stunt with St Peter.

You think it's easy to quit cold Turkey?