Storage structure for refrigerator appliance

A refrigerator with an adjustable shelf comprising:

• a food compartment with a rear wall and a door configured to provide access to the food compartment;
• and
• an adjustable shelf for storing food items within the food compartment, the adjustable shelf attached to the rear wall and comprising:
• a first shelf portion for supporting food items thereon, comprising a first planar support surface that is arranged normal to the rear wall;
• a second shelf portion for supporting food items thereon, comprising a second planar support surface, the second shelf portion being slidably moveable relative to the first shelf portion between an extended position and a retracted position, wherein at the extended position, the second shelf portion is arranged relative to the first shelf portion such that the second planar support surface is substantially coplanar with the first planar support surface, and wherein at the retracted position, a majority of the second planar support surface is arranged subjacent to the first planar support surface;
• a frame configured to support the first and the second shelf portions, wherein the frame includes two opposed side arms that each include a main track that guides the second shelf portion as the second shelf portion is slidably moved between the extended and retracted positions;
• an auxiliary external track disposed on an extended lower edge of the frame, the auxiliary external track following the main track;
• and
• a hook member attached to and protruding downwards from the second shelf portion, the hook member engaging with and sliding along the auxiliary external track to minimize lateral movement of a front end of the second shelf portion as the second shelf portion is slidably moved between the extended and retracted positions.