ABSTRACT
Fascia has traditionally been thought of as a passive structure that envelops muscles, and the term “fascia” has been misused and confusing. However, it is now evident that fascia is a dynamic tissue with complex vasculature and innervation. A definition of fascia as an integral tissue has been provided here, highlighting the main features of the superficial and deep fasciae. The superficial fascia (fascia superficialis) is a membranous layer of connective tissue formed by loosely packed interwoven collagen fibers mixed with abundant elastic fibers. Thicker in the trunk than in the limbs, they gradually become thinner in the limbs peripherally. Functionally, the superficial fascia can participate in the integrity of the skin and provide support for subcutaneous structures. The deep fascia is a fibrous layer that covers muscle bundles. Two different types of deep fascia can be distinguished: aponeurotic fascia and epimysial fascia. The first type includes the fasciae of the limbs, the thoracolumbar fascia, and the rectus sheath. The second is typical of the deep fasciae of the trunk, as well as those of the pectoralis major, trapezium, deltoid, and gluteus maximus muscles.
