A medical device includes an end effector at a distal end of the medical device, an actuator coupled to a proximal end of the end effector, a pivot arm pivotally coupled to the end effector distal of the proximal end of the end effector, where actuation of the actuator pivots the end effector relative to the pivot arm, and a lock on the end effector and the pivot arm, where the lock has a first state permitting the end effector to pivot relative to the pivot arm and a second state restricting the end effector from pivoting relative to the pivot arm.