subkutaanne

Subkutaanne, in medical terms, refers to the subcutaneous tissue or hypodermis—the layer of tissue located directly beneath the skin. In humans it lies between the dermis and the underlying muscles and fascia. It consists mainly of loose connective tissue and adipose tissue, with small blood vessels, nerves, and lymphatics.

Structure and variation: The subcutaneous layer is organized into lobules by connective tissue septa. Its thickness varies by anatomical site, age, sex, and body composition. It is continuous with the superficial fascia that envelops underlying structures. In some animals there is a panniculus carnosus, a muscle layer associated with the subcutaneous tissue; in humans this muscle layer is vestigial. The subcutaneous tissue is not part of the skin proper, but rather lies beneath it.

Functions: The tissue provides insulation to regulate body temperature, a reservoir for energy storage in the form of fat, and mechanical cushioning to protect deeper structures from impact. It also serves as a site for storage of hormones and metabolic substrates and participates in body contouring and signaling.

Clinical relevance: Subcutaneous tissue is the target for certain routes of medication administration, notably subcutaneous injections. Common injection sites include the outer upper arm, the abdomen (avoiding the navel area), and the thigh; technique depends on needle size, insertion angle, and patient adiposity. Repeated injections can lead to lipodystrophy or lipohypertrophy. Subcutaneous edema or inflammation can occur in various disease states.

Imaging and pathology: Subcutaneous fat can be evaluated by ultrasound, computed tomography, or magnetic resonance imaging. Benign lesions such as lipomas can arise in this layer, as can lipodystrophy syndromes and inflammatory conditions affecting the subcutaneous tissue.