hand mudra basically mean holding ur hand in particular position. They were used in traditions of Hinduism, BudDhism & various others including Kungfu. They could also be used in improving health, each hand mudra provides specific purpose  & most of the mudras can be done at anytime
for eg:
1  Gyan Mudra : This hand mudra requires you to touch the tip of your thumb to the tip of your index finger, with the other three fingers stretched out.
benefits: Increases memory power and sharpens the brain
- Enhances concentration and prevents Insomnia
- Regular practice ensures the cure of psychological disorders such as hysteria, anger, depression and other mental problems.

2 Prithvi Mudra: This hand mudra requires you to touch the tip of the ring finger with the tip of the thumb, while stretching out the other three fingers.
benefits: It helps to increase the weight of weak people.
- It improves the complexion of skin by making it glow.
- It makes the body healthy and active

3 Prana Mudra : The practice of this hand mudra requires you to bend the ring finger and little finger and touch the tip of your thumb with their tips, while keeping the remaining two fingers stretched out.
Benefits:
- It helps immunity get better.
- It increases the power of eyes and brings down the incidence of eye related diseases.

there are many others. Just search GOOGLE with keyword  “hand mudras for health” u could see their description with pictures

just click this link to get GOOGLE search result for keyword “hand mudras for health”
http://www.google.co.in/#hl=en&cp=22&gs_id=6&xhr=t&q=hand+mudras+for+health&pf=p&sclient=psy-ab&site=&source=hp&rlz=1W1ADSA_en&pbx=1&oq=hand+mudras+for+health&aq=0&aqi=g1g-v2&aql=&gs_sm=&gs_upl=&bav=on.2,or.r_gc.r_pw.&fp=6398dcbefc24d6dc&biw=1016&bih=549

http://www.megaupload.com/?d=D4EQXWIP

this powerpoint presentation explains 10 hand mudras with picture & there various health benefits.