Deep fascia
Encyclopedia
Deep fascia is a layer of fascia
which can surround individual muscles, and divide groups of muscles into compartments.
This is the dense fibrous connective tissue
that interpenetrates and surrounds the muscles, bones, nerves and blood vessels of the body. It provides connection and communication in the form of aponeuroses, ligaments, tendons, retinacula
, joint capsule
s, and septa
. The deep fasciae envelop all bone (periosteum
and endosteum
); cartilage
(perichondrium
), and blood vessels (tunica externa) and become specialized in muscles (epimysium
, perimysium
, and endomysium
) and nerves (epineurium
, perineurium
, and endoneurium
). The high density of collagen
fibers is what gives the deep fascia its strength and integrity. The amount of elastin
fiber determines how much extensibility
and resilience it will have.
s that report the presence of pain (nociceptors); change in movement (proprioceptors); change in pressure and vibration (mechanoreceptors); change in the chemical milieu (chemoreceptors); and fluctuation in temperature (thermoreceptors)., Deep fascia is able to respond to sensory input by contracting; by relaxing; or by adding, reducing, or changing its composition through the process of fascial remodeling.
Deep fascia can contract. What happens during the fight-or-flight response
is an example of rapid fascial contraction . In response to a real or imagined threat to the organism, the body responds with a temporary increase in the stiffness of the fascia. Bolstered with tensioned fascia, people are able to perform extraordinary feats of strength and speed under emergency conditions. How fascia contracts is still not well understood, but appears to involve the activity of myofibroblasts. Myofibroblasts are fascial cells that are created as a response to mechanical stress. In a two step process, fibroblasts differentiate into proto-myofibroblasts that with continued mechanical stress, become differentiated myofibroblasts. Fibroblasts cannot contract, but myofibroblasts are able to contract in a smooth muscle
-like manner.
The deep fascia can also relax. By monitoring changes in muscular tension, joint position, rate of movement, pressure, and vibration, mechanoreceptors in the deep fascia are capable of initiating relaxation. Deep fascia can relax rapidly in response to sudden muscular overload or rapid movements. Golgi tendon organs operate as a feedback mechanism by causing myofascial relaxation before muscle force becomes so great that tendons might be torn. Pacinian corpuscles sense changes in pressure and vibration to monitor the rate of acceleration
of movement. They will initiate a sudden relaxatory response if movement happens too fast. Deep fascia can also relax slowly as some mechanoreceptors respond to changes over longer timescales. Unlike the Golgi tendon organs, Golgi receptors report joint position independent of muscle contraction. This helps the body to know where the bones are at any given moment. Ruffini endings respond to regular stretching and to slow sustained pressure. In addition to initiating fascial relaxation, they contribute to full-body relaxation by inhibiting sympathetic activity which slows down heart rate and respiration.
When contraction persists, fascia will respond with the addition of new material. Fibroblasts secrete collagen and other proteins into the extracellular matrix
where they bind to existing proteins, making the composition thicker and less extensible. Although this potentiates the tensile strength
of the fascia, it can unfortunately restrict the very structures it aims to protect. The pathologies resulting from fascial restrictions range from a mild decrease in joint range of motion
to severe fascial binding of muscles, nerves and blood vessels, as in compartment syndrome
of the leg. However, if fascial contraction can be interrupted long enough, a reverse form of fascial remodeling occurs. The fascia will normalize its composition and tone and the extra material that was generated by prolonged contraction will be ingested by macrophages within the extracellular matrix.
Like mechanoreceptors, chemoreceptors in deep fascia also have the ability to promote fascial relaxation. We tend to think of relaxation as a good thing, however fascia needs to maintain some degree of tension. This is especially true of ligaments. To maintain joint integrity, they need to provide adequate tension between bony surfaces. If a ligament is too lax, injury becomes more likely. Certain chemicals, including hormones, can influence the composition of the ligaments. An example of this is seen in the menstrual cycle
, where hormones are secreted to create changes in the uterine
and pelvic floor
fascia. The hormones are not site-specific, however, and chemoreceptors in other ligaments of the body can be receptive to them as well. The ligaments of the knee may be one of the areas where this happens, as a significant association between the ovulatory
phase of the menstrual cycle and an increased likelihood for an anterior cruciate ligament
injury has been demonstrated.
It has been suggested that manipulation of the fascia by acupuncture
needles is responsible for the physical sensation of qi
flowing along meridians
in the body, even though there is no physically verifiable anatomical or histological basis for the existence of acupuncture points or meridians.
Fascia
A fascia is a layer of fibrous tissue that permeates the human body. A fascia is a connective tissue that surrounds muscles, groups of muscles, blood vessels, and nerves, binding those structures together in much the same manner as plastic wrap can be used to hold the contents of sandwiches...
which can surround individual muscles, and divide groups of muscles into compartments.
This is the dense fibrous connective tissue
Dense regular connective tissue
Dense regular connective tissue provides connection between different tissues. The collagen fibers in dense regular connective tissue are bundled in a parallel fashion.-Structures formed:* An example of their use is in tendons...
that interpenetrates and surrounds the muscles, bones, nerves and blood vessels of the body. It provides connection and communication in the form of aponeuroses, ligaments, tendons, retinacula
Retinaculum
Occurs where in some places, groups of tendons from separate muscle pass under a band of connective tissueRetinaculum, from the Latin verb retinere , plural: retinacula may be:* In the wrist:** Flexor retinaculum of the hand...
, joint capsule
Joint capsule
An articular capsule is an envelope surrounding a synovial joint.-Layers:Each capsule consists of two layers:* an outer layer composed of avascular white fibrous tissue...
s, and septa
Septum
In anatomy, a septum is a wall, dividing a cavity or structure into smaller ones.-In human anatomy:...
. The deep fasciae envelop all bone (periosteum
Periosteum
Periosteum is a membrane that lines the outer surface of all bones, except at the joints of long bones. Endosteum lines the inner surface of all bones....
and endosteum
Endosteum
In anatomy the endosteum is a thin layer of connective tissue that lines the surface of the bony tissue that forms the medullary cavity of long bones. This endosteal surface is usually resorbed during long periods of malnutrition, resulting in less cortical thickness...
); cartilage
Cartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
(perichondrium
Perichondrium
The perichondrium is a layer of dense irregular connective tissue which surrounds the cartilage of developing bone. It consists of two separate layers: an outer fibrous layer and inner chondrogenic layer. The fibrous layer contains fibroblasts, which produce collagenous fibers. The chondrogenic...
), and blood vessels (tunica externa) and become specialized in muscles (epimysium
Epimysium
Epimysium is a layer of connective tissue, which ensheaths the entire muscle. It is composed of dense irregular connective tissue. It is continuous with fascia and other connective tissue wrappings of muscle including the endomysium, and perimysium. It is also continuous with tendons where it...
, perimysium
Perimysium
Perimysium is a sheath of connective tissue that groups muscle fibers into bundles or fascicles.Recent advances in muscle physiology suggest that the perimysium plays a role in transmitting lateral contractile movements...
, and endomysium
Endomysium
The endomysium, meaning within the muscle, is a layer of connective tissue that ensheaths a muscle fiber and is composed mostly from reticular fibers. It also contains capillaries, nerves, and lymphatics...
) and nerves (epineurium
Epineurium
The epineurium is the outermost layer of connective tissue surrounding a peripheral nerve. It is made of dense irregular connective tissue and usually contains multiple nerve fascicles as well as blood vessels which supply the nerve...
, perineurium
Perineurium
In the peripheral nervous system, nerve fibers are each wrapped in a protective sheath known as the endoneurium. These are bundled together into groups known as fascicles, each surrounded by a protective sheath known as the perineurium. Several fascicles may be in turn bundled together with a blood...
, and endoneurium
Endoneurium
The endoneurium, also referred to as an endoneurial channel, sheath or tube, is a layer of delicate connective tissue made up of endoneurial cells that encloses the myelin sheath of a spinal cord nerve fiber. These are bundled up into groups called nerve fascicles, which have a protective sheath...
). The high density of collagen
Collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...
fibers is what gives the deep fascia its strength and integrity. The amount of elastin
Elastin
Elastin is a protein in connective tissue that is elastic and allows many tissues in the body to resume their shape after stretching or contracting. Elastin helps skin to return to its original position when it is poked or pinched. Elastin is also an important load-bearing tissue in the bodies of...
fiber determines how much extensibility
Extensibility
In software engineering, extensibility is a system design principle where the implementation takes into consideration future growth. It is a systemic measure of the ability to extend a system and the level of effort required to implement the extension...
and resilience it will have.
Examples
Examples include:- Fascia lataFascia lata-Thickness:It is an investment for the whole of the thigh, but varies in thickness in different parts.Thus, it is thicker in the upper and lateral part of the thigh, where it receives a fibrous expansion from the Glutæus maximus, and where the Tensor fasciæ latæ is inserted between its layers; it...
- Fascia cruris
- Brachial fasciaBrachial fasciaThe brachial Fascia is continuous with that covering the Deltoideus and the Pectoralis major, by means of which it is attached, above, to the clavicle, acromion, and spine of the scapula; it forms a thin, loose, membranous sheath for the muscles of the arm, and sends septa between them; it is...
- Buck's fasciaBuck's fasciaBuck's fascia is a layer of deep fascia covering the penis.It is also known as the "deep fascia of the penis".It is also sometimes simply called the "fascia of the penis", and the Terminologia Anatomica is simply "fascia penis"....
Fascial dynamics
Deep fascia is less extensible than superficial fascia. It is essentially avascular, but is richly innervated with sensory receptorSensory receptor
In a sensory system, a sensory receptor is a sensory nerve ending that responds to a stimulus in the internal or external environment of an organism...
s that report the presence of pain (nociceptors); change in movement (proprioceptors); change in pressure and vibration (mechanoreceptors); change in the chemical milieu (chemoreceptors); and fluctuation in temperature (thermoreceptors)., Deep fascia is able to respond to sensory input by contracting; by relaxing; or by adding, reducing, or changing its composition through the process of fascial remodeling.
Deep fascia can contract. What happens during the fight-or-flight response
Fight-or-flight response
The fight-or-flight response was first described by Walter Bradford Cannon....
is an example of rapid fascial contraction . In response to a real or imagined threat to the organism, the body responds with a temporary increase in the stiffness of the fascia. Bolstered with tensioned fascia, people are able to perform extraordinary feats of strength and speed under emergency conditions. How fascia contracts is still not well understood, but appears to involve the activity of myofibroblasts. Myofibroblasts are fascial cells that are created as a response to mechanical stress. In a two step process, fibroblasts differentiate into proto-myofibroblasts that with continued mechanical stress, become differentiated myofibroblasts. Fibroblasts cannot contract, but myofibroblasts are able to contract in a smooth muscle
Smooth muscle
Smooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by...
-like manner.
The deep fascia can also relax. By monitoring changes in muscular tension, joint position, rate of movement, pressure, and vibration, mechanoreceptors in the deep fascia are capable of initiating relaxation. Deep fascia can relax rapidly in response to sudden muscular overload or rapid movements. Golgi tendon organs operate as a feedback mechanism by causing myofascial relaxation before muscle force becomes so great that tendons might be torn. Pacinian corpuscles sense changes in pressure and vibration to monitor the rate of acceleration
Acceleration
In physics, acceleration is the rate of change of velocity with time. In one dimension, acceleration is the rate at which something speeds up or slows down. However, since velocity is a vector, acceleration describes the rate of change of both the magnitude and the direction of velocity. ...
of movement. They will initiate a sudden relaxatory response if movement happens too fast. Deep fascia can also relax slowly as some mechanoreceptors respond to changes over longer timescales. Unlike the Golgi tendon organs, Golgi receptors report joint position independent of muscle contraction. This helps the body to know where the bones are at any given moment. Ruffini endings respond to regular stretching and to slow sustained pressure. In addition to initiating fascial relaxation, they contribute to full-body relaxation by inhibiting sympathetic activity which slows down heart rate and respiration.
When contraction persists, fascia will respond with the addition of new material. Fibroblasts secrete collagen and other proteins into the extracellular matrix
Extracellular matrix
In biology, the extracellular matrix is the extracellular part of animal tissue that usually provides structural support to the animal cells in addition to performing various other important functions. The extracellular matrix is the defining feature of connective tissue in animals.Extracellular...
where they bind to existing proteins, making the composition thicker and less extensible. Although this potentiates the tensile strength
Tensile strength
Ultimate tensile strength , often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract...
of the fascia, it can unfortunately restrict the very structures it aims to protect. The pathologies resulting from fascial restrictions range from a mild decrease in joint range of motion
Range of motion
Range of motion , is the distance that a movable object may normally travel while properly attached to another object. It is also called range of travel, particularly when talking about mechanical devices and in mechanical engineering fields...
to severe fascial binding of muscles, nerves and blood vessels, as in compartment syndrome
Compartment syndrome
Compartment syndrome is a limb threatening and life threatening condition, defined as the compression of nerves, blood vessels, and muscle inside a closed space within the body . This leads to tissue death from lack of oxygenation due to the blood vessels being compressed by the raised pressure...
of the leg. However, if fascial contraction can be interrupted long enough, a reverse form of fascial remodeling occurs. The fascia will normalize its composition and tone and the extra material that was generated by prolonged contraction will be ingested by macrophages within the extracellular matrix.
Like mechanoreceptors, chemoreceptors in deep fascia also have the ability to promote fascial relaxation. We tend to think of relaxation as a good thing, however fascia needs to maintain some degree of tension. This is especially true of ligaments. To maintain joint integrity, they need to provide adequate tension between bony surfaces. If a ligament is too lax, injury becomes more likely. Certain chemicals, including hormones, can influence the composition of the ligaments. An example of this is seen in the menstrual cycle
Menstrual cycle
The menstrual cycle is the scientific term for the physiological changes that can occur in fertile women for the purpose of sexual reproduction. This article focuses on the human menstrual cycle....
, where hormones are secreted to create changes in the uterine
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
and pelvic floor
Pelvic floor
The pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus, and associated connective tissue which span the area underneath the pelvis. The pelvic diaphragm is a muscular partition formed by the levatores ani and coccygei, with which may be included the...
fascia. The hormones are not site-specific, however, and chemoreceptors in other ligaments of the body can be receptive to them as well. The ligaments of the knee may be one of the areas where this happens, as a significant association between the ovulatory
Ovulation
Ovulation is the process in a female's menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum . Ovulation also occurs in the estrous cycle of other female mammals, which differs in many fundamental ways from the menstrual cycle...
phase of the menstrual cycle and an increased likelihood for an anterior cruciate ligament
Anterior cruciate ligament
The anterior cruciate ligament is a cruciate ligament which is one of the four major ligaments of the human knee. In the quadruped stifle , based on its anatomical position, it is referred to as the cranial cruciate ligament.The ACL originates from deep within the notch of the distal femur...
injury has been demonstrated.
It has been suggested that manipulation of the fascia by acupuncture
Acupuncture
Acupuncture is a type of alternative medicine that treats patients by insertion and manipulation of solid, generally thin needles in the body....
needles is responsible for the physical sensation of qi
Qi
In traditional Chinese culture, qì is an active principle forming part of any living thing. Qi is frequently translated as life energy, lifeforce, or energy flow. Qi is the central underlying principle in traditional Chinese medicine and martial arts...
flowing along meridians
Meridian (Chinese medicine)
The meridian is a path through which the life-energy known as "qi" is believed to flow, in traditional Chinese medicine. There is no physically verifiable anatomical or histological basis for the existence of acupuncture points or meridians.- Main concepts :...
in the body, even though there is no physically verifiable anatomical or histological basis for the existence of acupuncture points or meridians.