A fascia (; : fasciae or fascias; adjective fascial; ) is a generic term for

macroscopic The macroscopic scale is the length scale on which objects or phenomena are large enough to be visible with the naked eye, without magnifying optical instruments. It is the opposite of microscopic. Overview When applied to physical phenome ...

membranous bodily structures. Fasciae are classified as superficial,

visceral In a multicellular organism, an organ is a collection of Tissue (biology), tissues joined in a structural unit to serve a common function. In the biological organization, hierarchy of life, an organ lies between Tissue (biology), tissue and an o ...

or deep, and further designated according to their anatomical location. The knowledge of fascial structures is essential in

surgery Surgery is a medical specialty that uses manual and instrumental techniques to diagnose or treat pathological conditions (e.g., trauma, disease, injury, malignancy), to alter bodily functions (e.g., malabsorption created by bariatric surgery s ...

, as they create borders for infectious processes (for example Psoas abscess) and haematoma. An increase in pressure may result in a compartment syndrome, where a prompt fasciotomy may be necessary. For this reason, profound descriptions of fascial structures are available in anatomical literature from the 19th century.

Function

Fasciae were traditionally thought of as passive structures that transmit mechanical tension generated by muscular activities or external forces throughout the body. An important function of muscle fasciae is to reduce friction of muscular force. In doing so, fasciae provide a supportive and movable wrapping for nerves and blood vessels as they pass through and between muscles. In the tradition of medical dissections it has been common practice to carefully clean muscles and other organs from their surrounding fasciae in order to study their detailed topography and function. However, this practice tends to ignore that many muscle fibers insert into their fascial envelopes and that the function of many organs is significantly altered when their related fasciae are removed. This insight contributed to several modern biomechanical concepts of the human body, in which fascial tissues take over important stabilizing and connecting functions, by distributing tensional forces across several joints in a network-like manner similar to the architectural concept of tensegrity. Starting in 2018 this concept of the fascial tissue serving as a body-wide tensional support system has been successfully expressed as an educational model with the Fascial Net Plastination Project. Fascial tissues – particularly those with tendinous or aponeurotic properties – are also able to store and release elastic potential energy.

Anatomical compartments

fascial compartment A fascial compartment is a section within the body that contains Skeletal muscle, muscles and nerves and is surrounded by deep fascia. In the human body, the Limb (anatomy), limbs can each be divided into two segments – the upper limb can be di ...

is a section within the body that contains

muscles Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...

and nerves and is surrounded by fascia. In the

human body The human body is the entire structure of a Human, human being. It is composed of many different types of Cell (biology), cells that together create Tissue (biology), tissues and subsequently Organ (biology), organs and then Organ system, org ...

, the limbs can each be divided into two segments: The

upper limb The upper Limb (anatomy), limbs or upper extremities are the forelimbs of an upright posture, upright-postured tetrapod vertebrate, extending from the scapulae and clavicles down to and including the digit (anatomy), digits, including all the musc ...

can be divided into the arm and the forearm and the sectional compartments of both of these – the fascial compartments of the arm and the fascial compartments of the forearm contain an anterior and a posterior compartment. The lower limbs can be divided into two segments – the

leg A leg is a weight-bearing and locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single, linear element cap ...

and the thigh – and these contain the fascial compartments of the leg and the fascial compartments of the thigh. File:Plastinated Human Thigh.jpg, Photo of cross-sectional slice from a plastinated human thigh. File:Schematic drawing of a transverse section of the thigh illustrating its fascial anatomy.webp, Schematic drawing of a transverse section of the thigh illustrating its fascial anatomy.

Clinical significance

Fascia itself becomes clinically important when it loses stiffness, becomes too stiff, or has decreased shearing ability. When inflammatory

fasciitis Fasciitis is an inflammation of the fascia, which is the connective tissue surrounding muscles, blood vessels and nerves. In particular, it often involves one of the following diseases: * Necrotizing fasciitis * Plantar fasciitis * Ischemic fasc ...

or trauma causes fibrosis and adhesions, fascial tissue fails to differentiate the adjacent structures effectively. This can happen after surgery, where the fascia has been incised and healing includes a

scar A scar (or scar tissue) is an area of fibrosis, fibrous tissue that replaces normal skin after an injury. Scars result from the biological process of wound repair in the skin, as well as in other Organ (anatomy), organs, and biological tissue, t ...

that traverses the surrounding structures.

Fascial Net Plastination Project

The Fascial Net Plastination Project (FNPP) is an anatomical research initiative spearheaded by fascia researcher Robert Schleip. The project aims to enhance the study of fascia through the technique of plastination. Led by an international team of fascia experts and anatomists, the FNPP resulted in the creation of a full-body fascia plastinate known as FR:EIA (Fascia Revealed: Educating Interconnected Anatomy). This plastinate provides a detailed view of the human fascial network, allowing for a better understanding of its structure and function as an interconnected tissue throughout the body. FR:EIA was unveiled at the 2021 Fascia Research Congress and is currently exhibited at the Body Worlds exhibition in Berlin. This project represents a significant contribution to the visualization of fascia and has the potential to influence future research in fields such as medicine, physical therapy, and movement science.

Terminology

There exists some controversy about what structures are considered "fascia" and how they should be classified. The current version of the International Federation of Associations of Anatomists divides into: * Fascia craniocervicalis * Fascia trunci ** Fascia parietalis ** Fascia extraserosalis ** Fascia visceralis * Fasciae membrorum * Fasciae musculorum ** Fascia investiens ** Fascia propria musculi

Previous terminology

Two former, rather commonly used systems are: * The one specified in the 1983 edition of Nomina Anatomica (NA 1983) * The one specified in the 1997 edition of Terminologia Anatomica (TA 1997)

Superficial

Superficial fascia is the lowermost layer of the

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...

in nearly all of the regions of the body, that blends with the reticular dermis layer. It is present on the face, over the upper portion of the sternocleidomastoid, at the

nape The nape is the back of the neck. In technical anatomical/medical terminology, the nape is also called the nucha (from the Medieval Latin rendering of the Arabic , ). The corresponding adjective is ''nuchal'', as in the term ''nuchal rigidity'' ...

of the

neck The neck is the part of the body in many vertebrates that connects the head to the torso. It supports the weight of the head and protects the nerves that transmit sensory and motor information between the brain and the rest of the body. Addition ...

and overlying the breastbone. It consists mainly of loose areolar and fatty

adipose Adipose tissue (also known as body fat or simply fat) is a loose connective tissue composed mostly of adipocytes. It also contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, Blood vessel, vascular endothel ...

connective tissue Connective tissue is one of the four primary types of animal tissue, a group of cells that are similar in structure, along with epithelial tissue, muscle tissue, and nervous tissue. It develops mostly from the mesenchyme, derived from the mesod ...

and is the layer that primarily determines the shape of a body. In addition to its subcutaneous presence, superficial fascia surrounds organs,

glands A gland is a Cell (biology), cell or an Organ (biology), organ in an animal's body that produces and secretes different substances that the organism needs, either into the bloodstream or into a body cavity or outer surface. A gland may also funct ...

and neurovascular bundles, and fills otherwise empty space at many other locations. It serves as a storage medium of

fat In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food. The term often refers specif ...

and

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

; as a passageway for lymph,

nerve A nerve is an enclosed, cable-like bundle of nerve fibers (called axons). Nerves have historically been considered the basic units of the peripheral nervous system. A nerve provides a common pathway for the Electrochemistry, electrochemical nerv ...

and blood vessels; and as a protective padding to cushion and insulate. Superficial fascia is present, but does not contain fat, in the eyelid, ear,

scrotum In most terrestrial mammals, the scrotum (: scrotums or scrota; possibly from Latin ''scortum'', meaning "hide" or "skin") or scrotal sac is a part of the external male genitalia located at the base of the penis. It consists of a sac of skin ...

penis A penis (; : penises or penes) is a sex organ through which male and hermaphrodite animals expel semen during copulation (zoology), copulation, and through which male placental mammals and marsupials also Urination, urinate. The term ''pen ...

and

clitoris In amniotes, the clitoris ( or ; : clitorises or clitorides) is a female sex organ. In humans, it is the vulva's most erogenous zone, erogenous area and generally the primary anatomical source of female Human sexuality, sexual pleasure. Th ...

. Due to its

viscoelastic In materials science and continuum mechanics, viscoelasticity is the property of materials that exhibit both Viscosity, viscous and Elasticity (physics), elastic characteristics when undergoing deformation (engineering), deformation. Viscous mate ...

properties, superficial fascia can stretch to accommodate the deposition of adipose that accompanies both ordinary and

prenatal Prenatal development () involves the embryonic development, development of the embryo and of the fetus during a viviparity, viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic develop ...

weight gain. After

pregnancy Pregnancy is the time during which one or more offspring gestation, gestates inside a woman's uterus. A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Conception (biology), Conception usually occurs ...

and weight loss, the superficial fascia slowly reverts to its original level of tension.

Visceral

Visceral fascia (also called subserous fascia) suspends the organs within their cavities and wraps them in layers of connective tissue membranes. Each of the organs is covered in a double layer of fascia; these layers are separated by a thin serous membrane. * The outermost wall of the organ is known as the parietal layer * The skin of the organ is known as the

viscera In a multicellular organism, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to a ...

l layer. The organs have specialized names for their visceral fasciae. In the brain, they are known as

meninges In anatomy, the meninges (; meninx ; ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in the subarachnoid spac ...

; in the heart they are known as pericardia; in the lungs, they are known as pleurae; and in the abdomen, they are known as peritonea. Visceral fascia is less extensible than superficial fascia. Due to its suspensory role for the organs, it needs to maintain its tone rather consistently. If it is too lax, it contributes to organ prolapse, yet if it is hypertonic, it restricts proper organ

motility Motility is the ability of an organism to move independently using metabolism, metabolic energy. This biological concept encompasses movement at various levels, from whole organisms to cells and subcellular components. Motility is observed in ...

Deep

Deep fascia is a layer of dense fibrous connective tissue which surrounds individual

muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...

s and divides groups of muscles into

s. This fascia has a high density of

elastin Elastin is a protein encoded by the ''ELN'' gene in humans and several other animals. Elastin is a key component in the extracellular matrix of gnathostomes (jawed vertebrates). It is highly Elasticity (physics), elastic and present in connective ...

fibre that determines its

extensibility Extensibility is a software engineering and systems design principle that provides for future growth. Extensibility is a measure of the ability to extend a system and the level of effort required to implement the extension. Extensions can be t ...

or resilience. Deep fascia was originally considered to be essentially avascular but later investigations have confirmed a rich presence of thin blood vessels. Deep fascia is also richly supplied with

sensory receptor Sensory neurons, also known as afferent neurons, are neurons in the nervous system, that convert a specific type of stimulus, via their receptors, into action potentials or graded receptor potentials. This process is called sensory transduc ...

s. Examples of deep fascia are fascia lata, fascia cruris, brachial fascia, plantar fascia, thoracolumbar fascia and Buck's fascia.

References

External links

Fascia Research
* {{Authority control Connective tissue