Vocal Nodules: small growth resembling tiny hard bumps forming on both vocal cords.  During vocal misuse, the cords rub each other creating tension while they vibrate.  Therefore, similarly to a callous, they will form exactly where the most pressure has been applied.  

Click on the links below for video examples:
http://www.entusa.com/vocal_cord_nodules.htm
http://www.entusa.com/tvc_nodule_2.htm