1.   A blood clot or some other particle of matter can block a key artery or blood vessel that feeds the brain.

2.   Police blocked routes all around the airport, creating huge traffic jams along key arteries that pass by.

3.   Police blocked routes all around the airport, creating huge traffic jams along key arteries that pass the airport.

4.   Daily gunbattles are waged for control of key arteries.

5.   Daily gun battles are waged for control of key arteries.

6.   Local army sources said Serbs appeared to be trying to cut the road between Split and Sarajevo, the key artery for any new troops getting into Bosnia.

7.   Road travel is increasingly dangerous, with KLA and police checkpoints blocking normal routes and daily gun battles waged for control of key arteries.

8.   Thousands of students blocked key arteries leading into the capital before marching to the Education Ministry in the city center.

9.   Traffic on both lanes of the key artery was blocked for more than an hour.

10.   Fresh fighting erupted Monday between Afghan government forces and the Taliban Islamic militia on a key artery east of the besieged capital Kabul, Afghan sources said here.