What is the subcutis?
The subcutis is the lowest of the three skin layers. It consists of closed connective tissue chambers filled with more or less fat cells. The fat is either absorbed into the cells from the blood or formed from carbohydrates directly in the cell.
The fat content of the subcutaneous tissue varies individually and according to gender and constitution. Hormonal influences also affect the fat content of the cells of the subcutaneous tissue.
The subcutis is firmly connected to the overlying dermis by strong connective tissue tracts. Such structures also connect it to underlying structures such as tendons, fascia or periosteum.
This connection can be so strong in some parts of the body that the subcutis becomes a uniform, non-sliding structure with its underlying layer. This is the case, for example, at the scalp, where it is then referred to as scalp rind.
In areas of the body where the skin is frequently pressed against underlying bone structures – such as the elbow, kneecap or heels – the subcutis forms bursae. They dampen the mechanical stress at these points.
Important tasks of the subcutis
Subcutaneous fat tissue is always located near blood vessels – each fat lobule has its own blood supply. Thus, fat can be rapidly released from the blood into the subcutaneous tissue and stored there in the event of an oversupply. Conversely, stored fat can be rapidly broken down and released into the blood when there is insufficient nutrition. Since fat has a higher calorific value than protein or carbohydrates, depot fat serves as a high-quality energy store.
The fat-filled, deformable connective tissue chambers vary in size (depending on the stress placed on the skin in the respective area) and allow the skin to move against the underlying surface.
The property of the subcutis to bind water in its subcutaneous tissue makes this skin layer an important factor in the water balance of our body.
What problems can the subcutis cause?
A phlegmon is a purulent inflammation of the subcutis that spreads over a large area.
Vascular inflammation can occur in the subcutaneous area (vasculitides of the fatty tissue).
Lipomas are benign adipose tissue tumors in the subcutis. A malignant fatty tissue tumor is called a liposarcoma.
