Endoscope with a bending section having a cut-out for a working channel

An endoscope comprising:

• a handle comprising a first handle wheel and a second handle wheel;
• a distal tip unit;
• a shaft connecting the distal tip unit to the handle and comprising a bending section and a central axis extending longitudinally, the first handle wheel being configured to bend the bending section along a first bending plane, and the second handle wheel being configured to bend the bending section along a second bending plane,
• the bending section comprising segments, an outer periphery, an inner lumen, and steering wire lumens comprising closed-periphery holes, the segments including a proximal end segment, a distal end segment and intermediate segments between the proximal end segment and the distal end segment, the segments being interconnected by hinge members, the inner lumen comprising an alternating pattern of recessed portions and lobes, the recessed portions being angularly aligned with the steering wire lumens, the lobes extending radially outwardly more than the recessed portions, and the lobes comprising a working channel tube lobe and other lobes;
• and
• a working channel tube defining at least a part of a working channel, the working channel tube extending from the handle through the shaft and being positioned in the working channel tube lobe,
• wherein a depth of the working channel tube lobe measured from the central axis of the bending section to a radially outwardmost point on a periphery of the working channel tube lobe gradually increases along the bending section so that the working channel tube is positioned closer to the outer periphery in the distal end segment than in the proximal end segment, and
• wherein a depth of each of the other lobes measured from the central axis of the bending section to a radially outwardmost point on a periphery of each of the other lobes is constant along the bending section.