Patent attributes
A marking apparatus includes a rigid cannula having a peripheral wall forming a lumen that carries an imaging marker. A lateral opening in the peripheral wall is open to the lumen. The lateral opening has a proximal extent and a distal extent. A closed-off distal portion is distal to the lateral opening. A resilient end wall extends downwardly from the peripheral wall at the distal extent of the lateral opening. A stylet has a distal end having a ramp. The stylet is slidably received within the lumen of the rigid cannula for movement in the lumen. The resilient end wall of the rigid cannula is configured to engage the ramp of the distal end of the stylet when the stylet is advanced through the lumen of the rigid cannula to an extended position to substantially close off the lateral opening of the rigid cannula.