Extra definition can be provided by prior distension of the sheath with, for example, a local analgesic agent following clinical examination, provided care is taken to prevent any air being iatrogenically introduced which will compromise the ultrasound image. | Extra definition can be provided by prior distension of the sheath with, for example, a local analgesic agent following clinical examination, provided care is taken to prevent any air being iatrogenically introduced which will compromise the ultrasound image. |