Swing prism endoscope

An endoscope configured to pass into a head of a human or animal subject, the endoscope comprising:

• (a) a handle, wherein the handle comprises a rotatable user input feature;
• (b) an elongate tubular member extending distally from the handle, wherein the tubular member comprises a proximal end and a distal end, wherein the tubular member defines a hollow tubular interior extending the length of the tubular member, wherein the tubular member further defines a central longitudinal axis;
• (c) a viewing window disposed at the distal end of the tubular member;
• (d) a pivotable prism disposed within the hollow tubular interior of the tubular member proximal to the distal end of the tubular member and within the length of the tubular member defining the viewing window, wherein the pivotable prism comprises a plurality of teeth, wherein the pivotable prism is configured to change a direction of view of the endoscope, wherein the user input feature is operable to adjust a viewing angle of the endoscope by pivoting the pivotable prism within the hollow tubular interior about a prism axis;
• and
• (e) a threaded shaft comprising a worm threaded portion, wherein the threaded shaft is rotatably disposed within the tubular member about a second longitudinal axis, wherein the second longitudinal axis is parallel to the central longitudinal axis, wherein the worm threaded portion is configured to engage the teeth of the pivotable prism, wherein the threaded shaft is configured to rotate about a second longitudinal axis within the tubular member to cause pivoting of the pivotable prism about the prism axis in response to rotation of the user input feature, wherein the prism axis is perpendicular to a plane bisecting the elongate tubular member, wherein the plane is parallel to the central longitudinal axis.