Rotatable carriage for an instrument holder

A manipulator arm for controlling movement of an instrument, the manipulator arm comprising:

• a plurality of links coupled by one or more joints;
• and
• an instrument holder configured to couple the one or more joints and plurality of links to the instrument,
• wherein the instrument holder comprises:
• a base member,
• a carriage configured to releasably attach to the instrument and drive the instrument, wherein the carriage comprises a central axis and a lateral opening extending radially outward from central axis, the lateral opening configured to receive a portion of the instrument from external the carriage along a direction substantially perpendicular to the central axis, and
• a positioning member positionable adjacent the lateral opening such that the carriage is rotatable with respect to the base member about the central axis to an angular extent such that the lateral opening is configured to rotate past the base member,
• wherein the carriage houses one or more drive elements configured to transmit mechanical force to the instrument in a coupled state of the instrument with the carriage, wherein the one or more drive elements are driven in response to electrical signal communication with the one or more drive elements.