Which of the following correctly describes the hyponychium?

The hyponychium is correctly described as the slightly thickened layer of skin located beneath the free edge of the nail. This area serves a critical function in protecting the area where the nail plate meets the skin. It acts as a barrier against pathogens and helps prevent the entry of dirt and microorganisms, ensuring the nail stays healthy. The hyponychium also helps with the overall stability and adhesion of the nail to the underlying skin, playing a key role in nail health.

In contrast to this correct description, the other options mention structures and areas related to the nail but do not accurately capture the specific role or location of the hyponychium. The fold of skin overlapping the side of the nail pertains to the nail fold, while the portion of living skin that supports the nail plate refers to the nail bed. The option concerning a furrow on each side of the nail describes the lateral nail grooves, which are also distinct from the hyponychium. Each of these alternatives highlights different components of nail anatomy, but only the description of the hyponychium as the thickened layer below the free edge captures its unique attributes and purpose accurately.