Abstract: A siderail assembly comprises a siderail body, a siderail linkage, and a locking mechanism. The siderail linkage is configured to movably couple the siderail body to a frame of a person-support apparatus. The siderail linkage is configured to move the siderail body between a first position and a second position with respect to the frame. The siderail linkage includes a guide member. The locking mechanism includes a housing with a slot that defines a guide. The guide member is configured to move along the guide between a first guide position and a second guide position as the siderail body moves between the first position and the second position.