What Is Subcutaneous Tissue?

The subcutaneous tissue is a layer beneath the skin that protects the body’s muscles, bones and internal organs. It also stores fat and helps control temperature. People often use it to inject medicine.


A 53-year-old woman presented with a rapidly enlarging nodular lesion. US demonstrated an elongated fluid collection overlying a straight echogenic appearance of fascia lata. This is characteristic of a Morel-Lavallee lesion.

It stores fat

Subcutaneous tissue (also known as adipose tissue, superficial fascia, tela subcutanea) is an important site for fat storage in the body. It also helps protect the body against shock and acts as an insulator. This layer also provides a backup source of energy and helps regulate body temperature. It contains adipose cells that can swell and shrink, and secrete leptin, a hormone that controls appetite and signals when the body has eaten enough.

This layer is thicker in some areas of the body than in others, and is usually found near muscles, bones, blood vessels, and organs. It is especially thick in the abdominal area, where it can reach up to 3 centimeters deep. It is composed of loose connective tissue, fat cells, and blood vessels.

Subcutaneous fat helps the body insulate against cold and absorb shock from falls. It also plays a role in controlling body temperature and providing structural support for the skin. In some cases, excess subcutaneous fat can be a sign of obesity. However, healthy eating and exercise can help you burn excess fat and maintain a healthy weight.

It protects the body

Just like the armor that medieval knights wore to protect themselves from arrows and swords, the subcutaneous layer of your body protects muscles, bones and other delicate tissues. It connects the skin to the underlying fascia (fibrous tissue) and contains fat cells called adipocytes that store energy. It also insulates the body and helps regulate temperature.

It also cushions the body and prevents muscles from rubbing against each other, protecting them from injury. This is important because the bones, muscles and organs underneath the skin need to be protected from physical damage. The subcutaneous tissue does this by storing excess fat around the body to cushion it and protect it from injury.

In the event of a trauma, subcutaneous fat can be disrupted and form a lesion such as a hematoma or abscess. Hemorrhagic fat infiltration can be seen by US as a hyperechoic area surrounding a discontinuity of fat lobules. In some cases, the trauma may extend to deeper structures such as muscle or tendon sheaths. These lesions can be distinguished by US as bright linear images with posterior acoustic shadowing (arrowheads) that interrupt the normal tissue layers.

It is a good place to inject medicine

Subcutaneous injections are a good way to deliver medications that require slow absorption, such as insulin for diabetes. They are also used for autoimmune diseases such as arthritis. The most common sites for this type of injection are the upper arm, belly area (about 2 inches away from the belly button), and buttocks. Before injecting, make sure that the skin is healthy and not irritated or reddened. Clean the area with an alcohol pad and let it dry. You should also change injection sites each time to prevent scar tissue.

Injections into the subcutaneous tissue are less painful than intramuscular injections because the needles are smaller and don’t have to push through as much muscle tissue. If you are afraid of needles, ask your doctor to use a numbing cream or distract yourself with a movie or game before giving the shot. You should also try to breathe deeply and keep your hands warm, especially if you have young children or someone with anxiety about needles.

It can develop tumors

The subcutaneous tissue is a layer of fat cells that lies beneath the skin and connects to other tissues under it, such as muscles and bones. It provides insulation and helps regulate body temperature. It also stores energy. Depending on a person’s nutrition habits, this layer can vary in thickness. Men tend to have more fat in this area, while women accumulate it mainly in their hips and buttocks.

The most common lesions involving the subcutaneous tissue are soft-tissue masses. These can range from benign cysts to a variety of tumors. Typical lesions include lipomas, hemangiomas, and metastases. Histopathologically, these masses are characterized by an inflammatory infiltrate and loose fibrous scars.

Hematomas of the subcutaneous tissue resemble a hyperechoic fluid collection on US images. However, the appearance of these collections varies over time. In some cases, they may liquefy and develop a more solid appearance. In contrast, hemangiomas are more likely to demonstrate a port-wine stain and exhibit slow blood flow with sparse Doppler signals (Paltiel et al. 2000).

It can develop panniculitis

Panniculitis is a group of inflammatory diseases that affect the layer of fat beneath the skin (subcutaneous tissue). The condition is characterized by painful, red, swollen bumps called nodules. These bumps are often located on the thighs, but they can also be found on the arms, buttocks, trunk, and face. Panniculitis can be caused by infections, injuries, or autoimmune conditions.

Diagnosis of panniculitis depends on the history, physical examination, and laboratory tests. The symptoms vary according to the cause, but can include tender red nodules that fade after a few days or weeks. The bumps may also leave a groove, or indentation, on the surface of the skin.

Traumatic panniculitis presents as indurated, warm, red, subcutaneous nodules and plaques. Histopathology can reveal fat microcysts surrounded by histiocytes, foam cell infiltrate, and lipomembranous changes. Bacterial panniculitis is characterized by extensive lobular neutrophil-dominated infiltrate with suppurative granulomas and perivascular inflammation. Other histopathologic findings include edema, fibrosis, and calcific lesions.