I have this image and I want to divide the leg to 10 part equally horizontal . How can I do this?

Hi.

Try this.

This might be one way to do it if you don't mind tiny gaps:

1. draw a rectangle which has a very small height of let's say 0.001mm (hard to see) and a width which is larger than the width of your leg.
2. align the rectangle with the top of your leg (Shift+Ctrl+A)
3. make a copy of that rectangle and align it with the bottom of your leg (Shift+Ctrl+A)
4. make 9 more copies (Ctrl+C, Ctrl+V) of the rectangle and place them somewhere inbetween the top and bottom rectangle
5. select all 11 rectangles and distribute them equally in vertical direction (Shift+Ctrl+A)
6. Combine these 11 rectangles (Ctrl+K)
7. Select your leg and the rectangles and use Path|Difference or (Ctrl+ -)
8. Select the remaining object and use Path|Break Appart or (Shift+Ctrl+K)

Then you should have 10 (almost) vertically equal parts.
There might be smarter ways to do that but that's the first way which comes to my mind.

This is one of the many situations in Inkscape, where there are several ways to accomplish something. Here's what I would do. Take the height of the leg and divide by 10. That's how tall each piece needs to be.

Duplicate the leg, and shorten it to the height you calculated. Use a grid or guides and snapping to move into position. Duplicate the small piece, and move into place. Repeat until finished.

Just for the records...
I played a little more and found a way which works also for odd shaped objects and any cuts as well (see example below).
Actually it's pretty forward: Instead of drawing rectangles or duplicating things you just draw your desired cutting lines.

1. draw your cutting lines (F6) and make sure that the cutting lines are on top (Object|Raise to top) or (Home)
2. select them all and combine them (Ctrl+K)
3. set their stroke to 0px (from now on you won't see them anymore, so remember where they are to be able to select them)
4. select your object and the cutting lines and use Path|Division (Ctrl+/)

If you need e.g. precise equidistant horizontal cuts:
1. draw the cutting lines (number of desired pieces plus one) somewhere arbitrarily distributed whithin the height of your object to cut
2. select them all and distribute them equidistantly in vertical direction (Shift+Ctrl+A). No top or bottom alignment with object necessary.
3. select the cutting lines and combine them (Ctrl+K) and set their stroke to 0px
4. set the height of the combined cutting lines to the same value as the height of your object
5. center the cutting lines and your object vertically (Shift+Ctrl+A)
6. select your object and the cutting lines and use Path|Division (Ctrl+/)

At least, this works on InkScape 0.91pre2 Win7.
However, even if with strike 0 you might see some tiny gaps between the divided objects on the screen. But as I understand this is because of rendering and a topic which still needs to be solved...