a medical instrument support mechanism , particularly suitable for ophthalmological instruments , including first and second support arms and a suitable base member in which the first arm is vertically pivotal with respect to the base member and the base member is pivotal with respect to another support member , such as a support pole . the second arm is also pivotally connected to the first arm . a locking mechanism is operatively connected to each of the pivot connections to allow an operator to selectively lock and unlock the pivot connections substantially simultaneously by operating a lever movable in a direction extending along the length of the first support arm . this lever is preferably disposed along a lower side of the first support arm and specifically operates screw locking mechanisms and respective clamp members .