A support arm for a medical device includes a column and a boom rotatably coupled to the column for rotation relative to a first axis. An arm is coupled to the boom for rotation relative to a second axis. A link mount is coupled to the arm and rotatable relative to the arm about a third axis. A device mount is supported by a linkage having link members arranged such that rotation of said first link member relative to the link mount about a fourth axis rotates the medical device about a fifth axis. The device mount is rotatable relative to the linkage about a sixth axis. The third, fifth and sixth axes extend through the center of mass of a medical instrument supported by the device mount.
