pressure distribution over the palm of the hands

Put the above words in google scholar search

You will get many references - I checked - thousands of siete will be shown

Not very useful answer.

Maybe I didn't express myself correctly. I want references about the implications of concentrated pressure on structures of the hand, particularly due to the use of hand tools (physiological ones).

I already did search at many bases, and I have many related references, but I found only papers about discomfort/pain thresholds, the implications of vibrating tools and so on. For example, the case of the pressure in median nerve (CTS) is very limited to that structure, so not very helpful.

What about the whole hand? The distal/medial/proximal phalanxs? What kinds of "damage" can I get into nerves, tendons, skin are related to the excessive pressure? How I'd know the acceptable limits? What pressure levels are related to some specific conditions?

The paper I mentioned above likely has safety limits to the pressure that hand skin can manage before it get damaged. That is some kind of data I want.

You might want to contact Novel GmbH in Munich, Germany or St. Paul, USA because they have developed sensors for measuring hand pressure ('manugraphy'). They could tell you who is using their devices for which kinds of application. Hope this helps...

Thanks Dieter.

Unfortunately, a few years ago I tried to contact Novel to buy its system and had no response at all. Then my team end up buying the Tekscan Grip Versatek (which is about to arrive here).

I found some articles about the pressure distribution. Most of them approached handling cylinders in MVC (maximum voluntary force). But I found only one which has some precise mention about the effects of the excessive pressure on hands. And that one refers to the study I've mentioned above.

I have my "base" reference very complete. I'm searching some more narrower approach now.

Danilo, I send you  the reference

Dear Colleague,

On the website http://handshoemouse.com/publications.html under "Research" you can find 3 dermatological publications (at the end of the list) that present hand palm skin effects as a consequence of problematic use of the computer mouse.

Maybe these papers are interesting for you too ?

With kind regards,

Koos Jaap van Zwieten

Thank you Koos.

If those symptons/diseases are due to computer use I wonder what happens with more forceful hand interfaces.

It doesn't deal with tools in particular, but you might find the article useful - It is about capillary closing pressures in the fingers.

http://circres.ahajournals.org/content/6/4/461.full.pdf

Thank you Paul.

Saving for further reading.

Hi Danilo,

My research is quite similar to yours. For my Ph.D. I developed a 3D hand model for ergonomic tool handle design. The second part of the thesis is a finite element model of a fingertip and development of a targeted bioinspired foam material for handheld products to lower contact pressure. A significant part of my work therefore relies on contact pressure and also resulting risks of acute and also cumulative trauma disorder development. 

From literature review I can say there has been little done in the field of the determination what pressure does what damage as this is very difficult to define, measure and analyse. Therefore researchers usually provide recommendations for the maximum value of peak contact pressures or limits (pressure discomfort threshold, pressure pain threshold,...). 

I also published some papers, which I can provide you with. Some of them address contact pressure directly, some of them  indirectly, however all of them have many relevant references which could be helpful to you. I am also available for any discussion.

I just remembered that the Novel Award in 2010 went to a paper on hand pressures in cycling. Maybe this is helpful...

http://www.ncbi.nlm.nih.gov/pubmed/21458120

Clin Biomech 2011;26(6):642-8. The influence of glove and hand position on pressure over the ulnar nerve during cycling. Slane J, Timmerman M, Ploeg HL, Thelen DG.

BACKGROUND: Chronic ulnar nerve compression is believed to be the primary cause of sensory and motor impairments of the hand in cyclists, a condition termed Cyclist's Palsy. The purpose of this study was to quantitatively evaluate the effects that hand position and glove type can have on pressure over the ulnar nerve, specifically in the hypothenar region of the hand.

METHODS: Thirty-six experienced cyclists participated. Subjects rode at a constant cadence and power output on a stationary bicycle with their hands in the tops, drops and hoods of a standard drop handlebar. A high resolution pressure mat was used to record hand pressure with no gloves, unpadded gloves, foam-padded gloves and gel-padded gloves. Wrist posture was simultaneously monitored with a motion capture system. Laser scans of the subject's hand were separately acquired to register pressure maps onto the hand anatomy.

FINDINGS: Average peak hypothenar pressures of 134-165kPa were recorded when cyclists did not wear gloves. A drops hand position induced the greatest hypothenar pressure and most extended wrist posture. Padded gloves were able to reduce hypothenar pressure magnitudes by 10 to 28%, with slightly better pressure reduction achieved using thin foam padding.

INTERPRETATION: The hand pressure magnitudes and loading patterns seen in steady-state cycling are of sufficient magnitude to induce ulnar nerve damage if maintained for long periods. Wearing padded gloves and changing hand position can reduce the magnitude and duration of loading patterns, which are both important to mitigate risk for Cyclist's Palsy during extended rides.

Thank you Dieter.

Sports may represent a great reference for that matter.

I found some medicine references about occupational skin diseases that mention some effects also.

I'm astounded that manual labor activities so frequent in countries geared toward agriculture like Brazil have no/so few studies about their interaction with tools like hoes, hacks, etc.

Time and pressure (more than 25mmHg) may be dangerous. Also repetitive pressure every days 

Your study seems particularly relevant to people who have sensory neuropathy and therefore increased risk of damage and ulcers due to excessive pressure. Maybe you can find some interesting references related to this, e.g., Hansen's disease.

Hi Danilo,

This article can contain matter of your interest related to the effort on the hands.

Science of Gymnastics Journal 2014. Vol. 6 Issue 1: 67 - 72. Thermal imagin of hands during simple gymnastics elements on the wooden bar with and without use of magnesium carbonate.

Abstract

The article describes investigation of effectiveness of magnesium carbonate in simple gymnastics. Students at the faculty of sports performed a simple element (one leg circle forward) while temperature of the bar and palms was measured with a thermal imager. In the first attempt they were using magnesium carbonate while in the second attempt they performed the element without magnesium carbonate. It was notable that with use of magnesium palm temperature rose, while during performance without magnesium the palm temperature was practically constant. Palm friction blisters are then expected to be less frequent when magnesium is not used, as the palm temperature does not rise (important effect of friction is warming of the bar surface and skin). As subjects did not report any grip problems, we could say that for easy elements without many repetitions not using of magnesium can be safe

Thank you Benjamin.

I will look at that in a moment.

Att.

Paul W. Brand, FRCS, and the bioengineers with whom he worked at the US Public Hearth Service, Carville, LA (USA) did considerable research regarding soft tissue response to stress.   The tree editions of his book, Clinical Mechanics of the Hand, contain synopses of this research.  Although these books are out of print, they continue to be highly regarded and prized in the hand/upper extremity surgery and rehabilitation fields.  You may be able to locate one or all of these books through your medical library; or the Internet.  Below are a few of Brand's journal publications that may pertain:

Brand, P. W. (2006). Pressure sore--the problem. J Tissue Viability, 16(2), 9-11.

MacMoran, J. W., & Brand, P. W. (1987). Bone loss in limbs with decreased or absent sensation: ten year follow-up of the hands in leprosy. Skeletal Radiol, 16(6), 452-459.

Brand, P. W. (1979). Management of the insensitive limb. Phys Ther, 59(1), 8-12.

Brand, P. W., & Ebner, J. D. (1969). Pressure sensitive devices for denervated hands and feet. A preliminary communication. J Bone Joint Surg Am, 51(1), 109-116.

Brand, P. W., & Ebner, J. D. (1969). A pain substitute pressure assessment in the insensitive limb. Am J Occup Ther, 23(6), 479-486.

Thank you very much Elaine. I'll check with a local librarian to get my hands on that book.

A very interesting feature discussions, which continue to follow!

Indeed few references there although in practice more empirical than scientific grounds, and I convinced myself that repeated high blood excess pressure, and other actions of mechanical nature can lead to damage to blood, vessels, nerves and muscles of course .... at hand!

Your trial will bring hope more documented information and therefore I welcome and I follow as good and important study!

my dear ,i agree with Dieter Rosenbaum