Subkutant

Subkutant, commonly referred to in English as subcutaneous tissue, is the layer of tissue located beneath the dermis and above the underlying fascia and muscles. It is also called the subcutis or hypodermis. In humans, it consists primarily of loose connective tissue and adipose (fat) tissue and contains vessels and nerve fibers that supply the skin.

The subcutaneous layer serves several functions: insulation to help regulate body temperature, energy storage in the form of fat, and cushioning to protect underlying structures. It acts as a conduit for nerves and blood vessels that supply the skin and for the diffusion of medications administered into this layer. The composition and thickness of subcutaneous tissue vary by location, age, sex, and body habitus.

Clinical relevance: The subcutaneous tissue is a common route for drug administration via subcutaneous injections (for example, insulin) and for the implantation of devices. Common injection sites include the abdomen, anterior thigh, and the outer upper arm, chosen based on fat distribution, accessibility, and risk of injury. Absorption from this layer is slower and more variable than intramuscular injection and depends on factors such as local blood flow and adiposity. Repeated injections at the same site can cause lipodystrophy, including lipohypertrophy or lipoatrophy, and may affect absorption.

Subcutaneous tissue is distinct from the dermis and from muscle tissue. In medical terminology, subcutaneous refers to anything beneath the skin; subcutis is a synonym used in anatomy. See also hypodermis, adipose tissue, intradermal and intramuscular.