1. An ultrasound accessory used for guiding an ultrasound transducer, comprising: (a) a first element adapted to be attached to an ultrasound transducer; and (b) a second element adapted for movement with respect to said first element, said second element having a surface adapted for contacting a subject to ultrasound examination, wherein said second element surface is comprised of an ultrasound permeable material, and a portion of ultrasound impermeable material smaller than said second element surface, wherein said portion of ultrasound impermeable material is located substantially in the center of said second element surface.