Putting His Finger on Hand Mechanics (9/13/2007)

Francisco Valero-Cuevas is stud, ying the biological, neurological and mechanical features of the human hand. - Photo Credit:

Using your iPod, waving goodbye, using your mouse to scroll down the length of this article. We take these seemingly simple hand functions for granted, blissfully unaware of the complicated system of neurons, muscles, bones and tendons at play in the simplest of gestures.

Francisco Valero-Cuevas is working to understand the biological, neurological and mechanical features of the human hand that make it possible to hold a fork, crack an egg or crumple a piece of paper.

His concurrent appointments at the USC School of Dentistry's division of Biokinesiology and Physical Therapy and the department of biomedical engineering at the USC Viterbi School of Engineering give him a unique opportunity to investigate this complex system from the engineering, neuroscience and clinical perspectives.

"You look at the hand and you think 'five fingers, what could be more straightforward?' " Valero-Cuevas said. "But really we don't understand well what a hand is biomechanically, how it is controlled neurologically, how disease impairs it and how treatment can best restore its function. It is difficult to know how each of its 30-plus muscles contributes to everyday functions like using your cell phone."

Valero-Cuevas came to USC from the Sibley School of Mechanical and Aerospace Engineering at Cornell University, where he and his team were engaged in projects funded by the National Institutes of Health, the Whitaker Foundation and the National Science Foundation.

By understanding the principles behind dexterous manipulation, he hopes his research will help those who have lost the use of their hands by guiding rehabilitation and helping to develop the next generation of prosthetics.

"As an analogy, I ask people to imagine going through life wearing boxing gloves. If you can grasp things in only the grossest of ways without fine manipulation, life is pretty difficult," he said. "Yet millions of people worldwide go through life without the full use of their hands. Diseases that affect the hand tend to disproportionately degrade quality of life."

Robotic and lifelike artificial limbs have been around for decades, he said, but they still lag behind their biological counterparts. "Surprisingly, the hook remains one of the more useful prosthetics," he said.

Valero-Cuevas hopes to apply his research directly to clinical populations, working with engineers and clinicians who are developing prosthetics to mimic the look and dexterity of our own hands.

In the end, our hands have a special significance to us. We use them when we talk, we paint them with ruby-red polish and adorn them with rings and bracelets.

"The hands have always been a part of the anatomy tied most to personal identity," Valero-Cuevas said. "We are nothing if not tool users. We interface with the world through our hands."

Note: This story has been adapted from a news release issued by the University of Southern California

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