The dermis has two layers: the papillary dermis on top and the reticular dermis below. Together, these layers sit between the outermost skin (the epidermis) and the deeper fat layer beneath. Though they’re both part of the same tissue, the two layers differ significantly in thickness, structure, and what they contain.
The Papillary Dermis
The papillary dermis is the thinner, upper layer. It sits directly beneath the epidermis and connects to it through a wavy, interlocking border called the dermal-epidermal junction. At this junction, finger-like projections from the dermis (called dermal papillae) reach upward into the epidermis, while ridges from the epidermis push downward into the dermis. This undulating pattern strengthens the bond between the two layers and improves the skin’s mechanical strength. Without it, the epidermis would shear off the dermis far more easily.
The papillary layer contains collagen fibers, fat cells, and fibroblasts, which are the cells responsible for producing collagen and maintaining the skin’s structural framework. It also houses tiny looping blood vessels called capillary loops, which deliver oxygen and nutrients to the epidermis above (since the epidermis itself has no blood supply). Nerve fibers and specialized touch receptors called Meissner corpuscles are concentrated here, making this layer especially important for detecting light touch and texture. Immune cells called phagocytes also patrol the papillary dermis, acting as a first line of defense against bacteria that breach the epidermis.
A network of small blood vessels called the subpapillary plexus runs along the bottom edge of this layer, right where the papillary and reticular dermis meet. This plexus feeds the capillary loops above and plays a role in regulating body temperature by controlling blood flow near the skin’s surface.
The Reticular Dermis
The reticular dermis is the thicker, deeper layer and makes up the bulk of the dermis. Its name comes from its net-like (reticulated) arrangement of dense collagen and elastin fibers. These protein fibers are what give skin its ability to stretch and snap back into shape. Collagen provides tensile strength, while elastin provides flexibility. As these fibers break down with age or sun exposure, skin loses firmness and begins to wrinkle.
This layer contains a much wider range of structures than the papillary dermis. Blood vessels, lymphatic channels, nerves, fat cells, sweat glands, sebaceous (oil) glands, and hair follicles all reside here. A deeper vascular network called the dermal plexus runs through this layer, supplying blood to the structures within it and feeding the subpapillary plexus above. Pressure-sensitive receptors called Pacinian corpuscles are found in the reticular dermis, allowing you to sense deep pressure and vibration, as opposed to the light-touch receptors in the papillary layer above.
Skin appendages like hair follicles, sweat glands, and oil glands originate from the epidermis but project deep into the reticular dermis. These structures depend on signals from the surrounding dermal tissue to develop and function properly. The arrector pili muscles, the tiny muscles that cause goosebumps, are also anchored in this layer.
How the Two Layers Work Together
The papillary and reticular layers aren’t separated by a sharp boundary. They blend into each other, with the papillary layer’s finer, loosely arranged fibers gradually transitioning into the reticular layer’s thick, tightly bundled ones. Together they provide a complete support system: the papillary layer handles sensation and nutrient exchange with the epidermis, while the reticular layer provides structural strength and houses the glands and follicles that keep skin lubricated, temperature-regulated, and protected.
The distinction between these layers matters in practical situations like burn assessment. A superficial dermal burn (sometimes called a superficial second-degree burn) damages the epidermis and extends into the upper papillary dermis. These burns are painful, blister, and typically heal on their own. A deep dermal burn penetrates into the reticular dermis, damaging hair follicles and glands. These burns heal more slowly and often result in significant scarring and skin contraction, sometimes requiring surgical intervention.
Why Skin Loses Structure Over Time
Both layers of the dermis thin as you age. The collagen and elastin network in the reticular dermis gradually degrades, reducing skin’s elasticity and firmness. The dermal-epidermal junction also flattens over time, meaning the interlocking ridges that hold the epidermis tightly to the dermis become less pronounced. This is one reason older skin tears and bruises more easily. UV exposure accelerates this process by breaking down elastin fibers in the reticular dermis faster than the body can replace them.
The papillary dermis also loses capillary density with age, which reduces nutrient delivery to the epidermis and contributes to the thinner, more translucent appearance of aging skin. Fibroblasts in both layers become less active, producing less collagen and slowing the skin’s ability to repair itself after injury.