Why touch the hem of His cloak?

Why would the woman from Matthew 9:20-22 have touched the edge or hem Jesus' cloak for healing? Why not His sandal, or hand, or head, or...

The answer comes from a better understanding of what Jesus would actually have been wearing, and from Malachi 4.

The tallith or tallet(h), also called talles, is a prayer shawl "cloak" that is worn during the morning Jewish services (the Shacharit prayers) in Judaism. It has special twined and knotted "fringes" known as tzitzit attached to its four corners. The tzitzit is sometimes also referred to as the arba kanfot, meaning the ‘four wings’ .

Now let us look at Malachi 4:1-3 :
"Surely the day is coming; it will burn like a furnace. All the arrogant and every evildoer will be stubble, and that day that is coming will set them on fire," says the LORD Almighty. "Not a root or a branch will be left to them. But for you who revere my name, the sun of righteousness [Messiah] will rise with healing in its [His] wings [tzitzit]. And you will go out and leap like calves released from the stall. Then you will trample down the wicked; they will be ashes under the soles of your feet on the day when I do these things," says the LORD Almighty."

She touched His hem to fulfill this Messianic prophesey! She probably did not know that Jesus was the Messiah at the time and was acting upon some supposed 'magical' healing property she thought existed in His robe. If however she did know Jesus was the messiah and acted upon this prophesey deliberately then that is even more womderful.