Glossary

A neurotransmitter released at the motor end plate that signals muscle fibers to contract. Excessive acetylcholine release at dysfunctional motor end plates is a key factor in the energy crisis hypothesis of trigger point formation, causing sustained sarcomere contraction.

A trigger point that is currently producing spontaneous pain or pain during normal activity. Unlike latent trigger points, active ones cause ongoing symptoms without direct palpation and are the primary clinical concern in myofascial pain syndrome.

A traditional Chinese medicine technique involving the insertion of fine needles at specific body points (meridians) to modulate pain and promote healing. While distinct from dry needling, acupuncture is sometimes used in myofascial pain management for its analgesic and muscle-relaxing effects.

Pain that has a recent onset, typically lasting less than three months, and serves as a protective warning signal. Acute pain from trigger points usually responds well to treatment, but left unaddressed it can transition to chronic pain through central sensitization mechanisms.

Abnormal bands of fibrous tissue that form between fascial layers or between fascia and muscle, restricting normal sliding and gliding. Adhesions develop from chronic inflammation, immobilization, or repetitive microtrauma and contribute to restricted range of motion and pain.

A sensory nerve fiber that carries signals from the periphery (skin, muscles, organs) toward the central nervous system. Afferent fibers from trigger points transmit nociceptive information to the dorsal horn of the spinal cord, where the signals are processed and can produce both local and referred pain perception.

A condition in which normally non-painful stimuli (light touch, mild pressure, or gentle movement) are perceived as painful. Allodynia indicates central nervous system sensitization and is commonly seen in chronic myofascial pain, fibromyalgia, and neuropathic pain states.

A muscle that opposes the action of another muscle (the agonist). When a trigger point causes shortening in an agonist muscle, the antagonist may develop compensatory overload, weakness, or its own trigger points. Treating trigger points in one muscle often requires addressing its antagonist as well.

The branch of the nervous system that controls involuntary body functions such as heart rate, blood flow, digestion, and sweating. Trigger points can produce autonomic symptoms including localized sweating, skin temperature changes, and vasoconstriction in their referred pain zones.

A technique that uses electronic monitoring to provide real-time information about physiological processes (muscle tension, skin temperature, heart rate variability) so patients can learn to control them. Surface electromyography biofeedback is used to teach patients how to reduce resting muscle tension in trigger-point-affected muscles.

The study of the mechanical principles governing human movement, including forces, leverage, and joint mechanics. Biomechanical analysis identifies movement patterns, postures, and loading strategies that predispose individuals to trigger point formation and guides corrective exercise interventions.

A potent inflammatory peptide released at sites of tissue damage that directly sensitizes nociceptors, lowering their activation threshold. Elevated bradykinin concentrations have been measured in the biochemical milieu of active trigger points and are believed to contribute to local tenderness.

The habitual grinding or clenching of teeth, often occurring during sleep. Bruxism is a major perpetuating factor for trigger points in the masseter, temporalis, and medial pterygoid muscles, and is a common contributor to temporomandibular disorders (TMD) and tension-type headaches.

A condition in which the central nervous system amplifies pain signals, making the spinal cord and brain more responsive to both painful and non-painful input. Persistent nociceptive bombardment from active trigger points can induce central sensitization, causing widespread pain and hypersensitivity.

A neuropeptide released by sensory nerve fibers that causes vasodilation and neurogenic inflammation. CGRP is found at elevated levels in active trigger points and plays a role in the local inflammatory milieu that maintains trigger point activity and referred pain.

Pain that persists beyond the normal tissue healing time, generally defined as lasting longer than three months. Chronic myofascial pain involves both peripheral (trigger point) and central (nervous system sensitization) mechanisms, requiring a multimodal treatment approach.

The most abundant structural protein in the body, forming the primary component of fascia, tendons, and ligaments. Collagen fiber alignment and cross-linking influence tissue stiffness, and abnormal collagen remodeling in chronically loaded fascia contributes to adhesion formation and myofascial restriction.

The structural framework of the body including fascia, tendons, ligaments, and cartilage. Connective tissue surrounds and interconnects all muscles and organs, and dysfunction in connective tissue (adhesions, fibrosis) is closely linked to myofascial pain and restricted mobility.

A sustained shortening of muscle or connective tissue that limits joint range of motion. The contraction knots found in trigger points represent localized contractures at the sarcomere level that persist without electrical stimulation, distinguishing them from true muscle spasm which involves motor nerve activity.

The primary stress hormone produced by the adrenal glands. Chronically elevated cortisol levels from sustained psychological or physiological stress impair tissue repair, promote muscle catabolism, and perpetuate trigger point activity by compromising the body's ability to resolve inflammation.

An audible or palpable crackling, grinding, or popping sensation in a joint during movement. While crepitus itself may be benign, its presence helps clinicians differentiate joint pathology from myofascial pain during a differential diagnosis.

The therapeutic application of cold to tissues using ice packs, cold sprays, or cold water immersion. Cryotherapy reduces blood flow, decreases inflammation, slows nerve conduction velocity, and provides analgesic effects. It is commonly used after trigger point treatment or during flare-ups to manage acute pain.

Small signaling proteins released by immune cells that regulate inflammation and pain. Pro-inflammatory cytokines such as IL-1 beta, IL-6, and TNF-alpha are elevated in the local biochemical environment of active trigger points, perpetuating the cycle of inflammation and nociceptor sensitization.

The process of eliminating or reducing the activity of a trigger point, converting it from an active, pain-producing state to a latent or resolved state. Deactivation methods include ischemic compression, dry needling, spray and stretch, and manual therapy techniques.

An area of skin supplied by sensory nerve fibers from a single spinal nerve root. Understanding dermatomes helps clinicians differentiate between radiculopathy (pain following a dermatome) and myofascial referred pain (which follows trigger point referral patterns that do not correspond to dermatomes).

A breathing technique that emphasizes activation of the diaphragm rather than the accessory respiratory muscles. Deep, slow diaphragmatic breathing activates the parasympathetic nervous system, reduces muscle tension, lowers cortisol levels, and is a fundamental self-management strategy for myofascial pain.

The posterior portion of the spinal cord gray matter where sensory neurons synapse and pain signals are processed before ascending to the brain. Sensitization of dorsal horn neurons by persistent trigger point input is a key mechanism in the transition from localized to widespread pain.

A treatment technique in which a thin filiform needle is inserted directly into a myofascial trigger point to elicit a local twitch response and disrupt the dysfunctional motor end plate. Dry needling reduces muscle tension, improves blood flow, and breaks the pain-spasm cycle. It is distinct from acupuncture.

A muscle contraction in which the muscle lengthens under load, generating high mechanical force per fiber. Eccentric loading is particularly effective at causing microtrauma to sarcomeres and is one of the primary biomechanical mechanisms of trigger point formation in athletes and active individuals.

A motor nerve fiber that carries signals from the central nervous system to muscles, glands, and organs. Efferent (motor) nerve dysfunction at the motor end plate is central to trigger point pathophysiology, as excessive neurotransmitter release drives the sustained sarcomere contraction.

A diagnostic technique that measures the electrical activity of muscles. EMG studies have demonstrated that trigger points exhibit spontaneous electrical activity at the motor end plate, even at rest, providing objective evidence of the neuromuscular dysfunction underlying trigger points.

Endogenous opioid peptides produced by the body that bind to opioid receptors and reduce pain perception. Exercise, laughter, and certain treatments stimulate endorphin release, contributing to pain relief. Aerobic exercise is recommended for myofascial pain partly because of its endorphin-boosting effect.

The leading theoretical model for trigger point formation, proposed by Simons. It suggests that excessive acetylcholine release at dysfunctional motor end plates causes sustained sarcomere contraction, which compresses local blood vessels, reduces oxygen supply, and creates a self-perpetuating cycle of energy depletion and contracture.

The science of designing workspaces, tools, and tasks to fit the human body and its capabilities. Poor ergonomic setups are among the most common perpetuating factors for trigger points, particularly in the upper trapezius, levator scapulae, and cervical muscles of office workers.

The network of proteins, glycosaminoglycans, and water that surrounds cells in connective tissue and provides structural support. Changes in extracellular matrix composition and hydration affect fascial stiffness and gliding, influencing trigger point formation and myofascial restriction.

A continuous web of dense connective tissue that envelops, separates, and connects every muscle, organ, bone, and nerve in the body. Fascia contains sensory nerve endings and can become a source of pain when restricted, fibrotic, or inflamed. It plays a central role in myofascial pain transmission.

An area where fascial layers become stuck together due to inflammation, immobilization, or chronic overload, preventing the normal sliding and gliding between tissue layers. Fascial adhesions restrict movement, increase mechanical stress on adjacent structures, and commonly coexist with trigger points.

An involuntary, visible twitching of muscle fibers under the skin caused by spontaneous discharge of motor units. While fasciculations are generally benign, they can occur near trigger points and should be differentiated from the local twitch response elicited during trigger point palpation or needling.

A chronic widespread pain condition characterized by diffuse musculoskeletal pain, fatigue, sleep disturbances, and cognitive dysfunction. Fibromyalgia and myofascial pain syndrome can coexist. Some researchers have proposed a relationship between persistent peripheral trigger point activity and the development of central sensitization, though this remains an area of active investigation.

A temporary worsening of symptoms, often triggered by overexertion, stress, poor sleep, or environmental changes. Flare-ups are a normal part of chronic myofascial pain management and do not necessarily indicate tissue damage. Learning to manage flare-ups is an important part of self-care.

A self-myofascial release technique using a cylindrical foam roller to apply sustained pressure to muscles and fascia. Foam rolling can reduce trigger point sensitivity, improve range of motion, and decrease perceived muscle soreness when performed consistently with appropriate pressure and duration.

A pain theory proposed by Melzack and Wall stating that non-painful sensory input (touch, pressure, vibration) can close neural "gates" in the spinal cord to painful input, reducing pain perception. This theory explains why rubbing a sore area or applying TENS provides pain relief.

A class of steroid hormones (including cortisol and synthetic variants like prednisone) that suppress inflammation. While glucocorticoid injections are sometimes used near trigger points, their effectiveness for myofascial pain is debated, and repeated injections can damage local tissue.

Long, unbranched polysaccharides (including hyaluronic acid) found in the extracellular matrix of connective tissue. GAGs attract and retain water, maintaining tissue hydration and lubrication. Dehydration of GAGs in fascia reduces tissue gliding and may contribute to fascial stiffness and trigger point perpetuation.

A sensory receptor located at the junction of muscle and tendon that detects changes in muscle tension. When tension exceeds a threshold, the Golgi tendon organ triggers an inhibitory reflex that causes muscle relaxation. This reflex is exploited in post-isometric relaxation and PNF stretching techniques for trigger point treatment.

The gel-like material that fills the space between cells and fibers in connective tissue, composed primarily of glycosaminoglycans and water. Ground substance viscosity affects fascial gliding; when it becomes more viscous due to inactivity or dehydration, tissue mobility decreases and trigger point susceptibility increases.

A protective muscle contraction that occurs reflexively in response to pain or anticipated pain. Guarding around trigger points can create a vicious cycle: the pain triggers guarding, which increases muscle tension, which perpetuates the trigger point, which produces more pain.

The body's ability to maintain stable internal conditions despite external changes. Trigger points represent a disruption of local tissue homeostasis, where the balance between contraction and relaxation, oxygen supply and demand, and inflammation and resolution is lost.

A glycosaminoglycan found in high concentrations between fascial layers that acts as a lubricant, allowing adjacent tissue layers to glide smoothly over one another. Research has shown that hyaluronic acid viscosity increases in myofascial pain conditions, reducing fascial gliding and contributing to stiffness.

An increased sensitivity to painful stimuli, where a normally painful stimulus is perceived as significantly more painful than expected. Hyperalgesia can be primary (at the site of injury or trigger point) or secondary (in surrounding tissues), reflecting peripheral and central sensitization respectively.

Excessive range of motion in joints beyond what is considered normal. Hypermobile individuals are prone to developing trigger points because their muscles must work harder to stabilize joints that lack ligamentous restraint, leading to chronic overload and fatigue.

A state of abnormally increased muscle tone or tension. Hypertonic muscles are often stiff, resist passive stretch, and are more likely to harbor trigger points. Hypertonicity can result from trigger point activity, neurological conditions, stress, or postural dysfunction.

A manual therapy technique using specially designed stainless steel or plastic tools to detect and treat fascial restrictions and trigger points. The instruments amplify tactile feedback, allowing clinicians to identify areas of tissue dysfunction and apply targeted treatment to break up adhesions.

An electrotherapy modality that uses two medium-frequency alternating currents that intersect and "interfere" within the targeted tissue, producing a deep-penetrating therapeutic current. IFC is used to reduce pain, decrease muscle spasm, and promote blood flow in trigger point treatment.

The body's biological response to tissue damage or infection, characterized by redness, heat, swelling, pain, and loss of function. While acute inflammation is protective and necessary for healing, chronic low-grade inflammation around trigger points perpetuates pain and prevents tissue resolution.

A needling technique developed by Dr. Chan Gunn that targets muscle shortening caused by neuropathy. While similar to dry needling, IMS specifically addresses muscles with segmental nerve dysfunction and uses the reflex relaxation triggered by needle insertion into shortened muscles.

A manual therapy technique in which sustained, gradually increasing pressure is applied directly over a trigger point to temporarily restrict blood flow. Upon release, a reactive hyperemia (blood flow surge) occurs, flushing out inflammatory mediators and restoring oxygen supply to the ischemic tissue.

A muscle contraction in which the muscle generates force without changing length (no joint movement occurs). Sustained isometric contractions, such as holding a static posture, are a common cause of trigger point development because they maintain metabolic demand without the rhythmic pumping action that aids blood flow.

A condition in which joints move beyond their normal range, often related to increased ligament laxity. Joint hypermobility syndrome is a significant predisposing factor for myofascial trigger points because muscles must compensate for reduced passive joint stability, leading to chronic muscular overload.

An involuntary flinching, wincing, or withdrawal response that a patient exhibits when an examiner palpates an active trigger point. The jump sign is a recognized clinical finding that supports the identification of a trigger point and is commonly associated with myofascial pain syndrome.

An elastic therapeutic tape applied to the skin to provide proprioceptive feedback, reduce pain, and support muscles without restricting range of motion. Some practitioners use kinesiology tape over treated trigger points to facilitate blood flow, reduce muscle spasm, and support the area during the post-treatment period.

The concept that the body's joints and segments are interconnected, so movement or dysfunction at one joint affects adjacent and distant segments. Trigger points in one muscle can alter movement patterns throughout the kinetic chain, causing compensatory overload and secondary trigger points in distant muscles.

A trigger point that is painful only when directly palpated and does not produce spontaneous pain. Latent trigger points still cause muscle dysfunction including reduced range of motion, weakness, and altered movement patterns, and they can become active under stress, overload, or fatigue.

A non-invasive therapy using low-intensity laser or LED light to stimulate cellular repair processes. Also called photobiomodulation, LLLT has shown moderate evidence for reducing trigger point pain and sensitivity by enhancing mitochondrial ATP production, reducing inflammation, and accelerating tissue repair.

A brief, involuntary contraction of the taut band fibers that occurs when a trigger point is stimulated by snapping palpation or needle penetration. The LTR is a spinal reflex and is considered both a supporting diagnostic finding and a therapeutic indicator during dry needling treatment.

A gentle manual therapy technique that promotes the flow of lymph fluid through the body. Improved lymphatic circulation helps remove inflammatory waste products and excess fluid from trigger point regions, supporting the resolution of local swelling and tenderness.

An umbrella term for hands-on treatment techniques including massage, joint mobilization, myofascial release, trigger point compression, and soft tissue manipulation. Manual therapy is a cornerstone of myofascial pain treatment, addressing both the trigger point and surrounding tissue dysfunction.

A sensory receptor that responds to mechanical stimuli such as pressure, stretch, vibration, and tissue deformation. Fascia is richly innervated with mechanoreceptors, which explains why manual therapy and movement-based treatments can modulate pain and improve proprioception in myofascial pain conditions.

A manual therapy technique involving rhythmic, passive movements applied to joints or soft tissues to restore normal motion. Joint mobilization complements trigger point treatment by addressing the joint restrictions that often develop secondary to muscle shortening from chronic trigger point activity.

The specialized region of a muscle fiber where a motor neuron synapses and releases acetylcholine to initiate muscle contraction. Motor end plate dysfunction, specifically excessive acetylcholine release, is central to the energy crisis hypothesis of trigger point formation and is the target of dry needling treatment.

A specialized sensory receptor within muscle tissue that detects changes in muscle length and rate of stretch. Muscle spindles play a role in the stretch reflex and contribute to muscle tone regulation. Altered muscle spindle sensitivity in hypertonic muscles may perpetuate trigger point activity.

A general term for muscle pain from any cause. Myalgia can result from trigger points, muscle strain, infection, medication side effects, or systemic disease. Myofascial pain from trigger points is distinguished from other forms of myalgia by the presence of taut bands, referred pain, and local twitch responses.

A chronic pain condition caused by myofascial trigger points in skeletal muscles and their associated fascia. MPS is characterized by regional pain, referred pain patterns, restricted range of motion, and palpable taut bands with trigger points. It is one of the most common causes of musculoskeletal pain worldwide.

A manual therapy technique that applies sustained pressure and stretch to fascial restrictions to restore tissue length, reduce pain, and improve mobility. Myofascial release addresses the fascial component of myofascial pain, complementing trigger point-specific treatments.

The contractile element within a muscle fiber, composed of repeating units called sarcomeres. Myofibrils contain the actin and myosin filaments responsible for muscle contraction. Dysfunction at the sarcomere level within myofibrils is fundamental to trigger point pathophysiology.

A condition in which a peripheral nerve is compressed or irritated by surrounding structures including hypertonic muscles, fascial restrictions, or taut bands associated with trigger points. Trigger points in muscles near peripheral nerves can cause numbness, tingling, and weakness that mimic radiculopathy.

The synapse between a motor neuron and a muscle fiber where acetylcholine is released to initiate contraction. Dysfunction at the neuromuscular junction, specifically at the motor end plate, is considered the primary site of trigger point pathology according to the integrated hypothesis.

The brain's ability to reorganize its structure and function in response to experience. In chronic myofascial pain, neuroplasticity can be maladaptive (amplifying pain through central sensitization) or therapeutic (retraining the nervous system to downregulate pain through graded exposure and movement therapy).

A protein complex that controls the transcription of genes involved in inflammation, immune response, and cell survival. NF-kB activation drives the production of pro-inflammatory cytokines at trigger point sites, contributing to the chronic inflammatory milieu that sustains trigger point activity.

A sensory nerve ending that detects potentially harmful stimuli (mechanical, thermal, or chemical) and transmits danger signals to the spinal cord and brain. Nociceptors in and around trigger points become sensitized by local inflammatory mediators, lowering their activation threshold and contributing to pain.

A class of medications (ibuprofen, naproxen, aspirin) that reduce inflammation and pain by inhibiting cyclooxygenase enzymes. While NSAIDs can provide temporary symptom relief for myofascial pain, they do not address the underlying trigger point pathology and may inhibit the inflammatory resolution process needed for tissue healing.

A phenolic compound found in extra-virgin olive oil that exhibits anti-inflammatory properties similar to ibuprofen. Oleocanthal inhibits cyclooxygenase enzymes and may contribute to the anti-inflammatory benefits of a Mediterranean-style diet in managing chronic musculoskeletal pain.

Essential polyunsaturated fatty acids (EPA and DHA) found in fatty fish, flaxseed, and walnuts that have potent anti-inflammatory effects. Omega-3 supplementation reduces the production of pro-inflammatory cytokines and promotes the synthesis of specialized pro-resolving mediators (resolvins) that help resolve chronic inflammation.

Subjecting a muscle to demands that exceed its current capacity for force production, endurance, or recovery. Overload is one of the primary activating factors for trigger points, occurring through acute trauma (sudden overstretch or contraction) or chronic overuse (repetitive submaximal loading without adequate recovery).

An imbalance between the production of reactive oxygen species and the body's ability to neutralize them with antioxidants. Oxidative stress is elevated in trigger point tissue due to local ischemia and metabolic dysfunction, contributing to tissue damage and nociceptor sensitization.

A negative cognitive-emotional response to actual or anticipated pain involving rumination, magnification, and feelings of helplessness. Pain catastrophizing amplifies pain perception, worsens disability, and predicts poorer treatment outcomes in chronic myofascial pain. Cognitive behavioral therapy can address catastrophizing patterns.

The use of hands and fingers to examine the body by touch. Skilled palpation is the primary diagnostic method for identifying trigger points, allowing clinicians to detect taut bands, nodules, local tenderness, referred pain patterns, and local twitch responses.

Any condition or behavior that sustains trigger point activity and prevents resolution despite treatment. Common perpetuating factors include poor posture, nutritional deficiencies (vitamin D, B12, iron), sleep disorders, chronic stress, hormonal imbalances, and joint hypermobility.

The use of low-level light therapy (laser or LED) to stimulate cellular function, reduce inflammation, and promote tissue repair. Photobiomodulation enhances mitochondrial cytochrome c oxidase activity, increasing ATP production in energy-depleted trigger point tissue and supporting the resolution of the local energy crisis.

A beneficial health outcome resulting from a patient's expectation of treatment effect rather than the treatment's specific mechanism. While the placebo effect contributes to all pain treatments, research demonstrates that trigger point therapies (especially dry needling) produce effects significantly beyond placebo in controlled trials.

A stretching technique that uses alternating muscle contraction and relaxation to increase range of motion. PNF stretching exploits post-isometric relaxation and reciprocal inhibition reflexes to achieve greater lengthening of muscles containing trigger points than passive stretching alone.

A muscle energy technique in which the patient gently contracts the target muscle against resistance for several seconds, followed by a relaxation phase during which the muscle is passively stretched further. PIR exploits the Golgi tendon organ reflex to reduce muscle tone and is highly effective for deactivating trigger points.

The gradual, systematic increase of stress placed on the body during exercise training. In myofascial pain rehabilitation, progressive overload is used to rebuild muscle capacity after trigger point deactivation, ensuring that muscles can tolerate increasing demands without reactivation of trigger points.

The body's sense of its own position, movement, and force in space, mediated by mechanoreceptors in muscles, tendons, joints, and fascia. Trigger points impair proprioception in affected muscles, contributing to poor coordination, altered movement patterns, and increased injury risk.

A deep muscle of the posterior abdominal wall that extends from the iliac crest to the 12th rib and lumbar vertebrae. Trigger points in the quadratus lumborum are one of the most common and overlooked causes of low back pain, referring pain to the hip, sacroiliac region, and lower abdomen.

The full extent of movement available at a joint. Active trigger points reduce range of motion in associated joints by causing muscle shortening, increasing resistance to stretch, and triggering protective guarding. Restored ROM after treatment is an objective measure of trigger point deactivation.

A neuromuscular reflex in which contraction of one muscle (the agonist) causes relaxation of its opposing muscle (the antagonist). This reflex is used therapeutically: contracting the muscle opposite to one containing a trigger point helps relax the affected muscle and facilitate stretch.

Pain perceived in a location distant from its actual source. Myofascial trigger points produce characteristic referred pain patterns that are remarkably consistent between individuals. Referred pain is mediated by convergence of sensory neurons at the spinal cord level and is a characteristic feature of trigger points.

The specific, reproducible distribution of pain that radiates from a trigger point to a distant area. Each muscle has documented referred pain patterns based on decades of clinical observation. These patterns are distinct from dermatomal patterns and are the foundation of trigger point diagnosis.

Specialized pro-resolving mediators derived from omega-3 fatty acids (EPA and DHA) that actively promote the resolution of inflammation. Unlike anti-inflammatory drugs that suppress inflammation, resolvins guide the inflammatory process to a natural conclusion, facilitating tissue repair and pain resolution.

The basic contractile unit of a muscle fiber, composed of overlapping actin and myosin filaments. In trigger points, sarcomeres become maximally shortened (contracted) and locked, forming the core of the contraction knot that characterizes the palpable nodule within a taut band.

A trigger point that develops in a muscle within the referred pain zone of another (primary) trigger point. Satellite trigger points form because the persistent nociceptive input from the primary trigger point sensitizes the spinal cord neurons that also serve the satellite muscle. Treating the primary trigger point often resolves satellite points.

Techniques that individuals perform on themselves to apply pressure to myofascial restrictions and trigger points using tools such as foam rollers, massage balls, and percussion devices. SMR is a cornerstone of self-management for myofascial pain, empowering patients to manage symptoms between clinical treatments.

An increase in the responsiveness of the nervous system to stimulation. Peripheral sensitization occurs at the nociceptor level (lowered activation threshold), while central sensitization occurs in the spinal cord and brain (amplified signal processing). Both forms contribute to the persistent pain experienced in chronic myofascial conditions.

Practices and habits that promote consistent, restorative sleep. Poor sleep is one of the most powerful perpetuating factors for myofascial trigger points because growth hormone (important for tissue repair) is released primarily during deep sleep, and sleep deprivation increases pain sensitivity and inflammatory markers.

A reflexive or voluntary restriction of movement in response to pain, functioning as a protective mechanism. Muscular splinting around trigger points reduces range of motion and can create a stiffening pattern that leads to secondary trigger point formation in adjacent muscles.

A trigger point treatment technique in which a vapocoolant spray is applied over the skin covering the trigger point and its referred pain zone while the muscle is passively stretched. The sudden cold stimulus activates cutaneous sensory fibers that inhibit pain transmission at the spinal cord level, allowing greater stretch.

A neuropeptide involved in the transmission of pain signals and neurogenic inflammation. Substance P is released by sensory nerve fibers at trigger point sites and in the spinal cord dorsal horn, where it amplifies pain signaling and promotes inflammation. Elevated Substance P levels have been measured in active trigger points.

A palpable, rope-like band of muscle fibers that contains a trigger point. The taut band represents a group of muscle fibers with sustained contraction (contracture) that can be felt running along the length of the muscle. Taut bands are a key diagnostic finding in myofascial pain and precede the identification of the trigger point nodule within them.

A condition affecting tendons, characterized by pain, swelling, and impaired function. Trigger points in muscles can produce chronic tension on their tendons, contributing to tendinopathy. Conversely, chronic tendon pain can cause secondary trigger points in the associated muscle as a protective response.

A non-invasive pain relief modality that delivers low-voltage electrical currents through electrodes placed on the skin. TENS works primarily through the gate control theory, where the electrical stimulation activates large-diameter sensory fibers that inhibit pain transmission at the spinal cord level.

Structured physical activities prescribed to restore function, reduce pain, and prevent recurrence. After trigger point deactivation, therapeutic exercises including stretching, strengthening, and motor control training are an important part of addressing the underlying dysfunction and reducing the likelihood of trigger point reactivation.

The therapeutic application of heat to tissues using hot packs, warm baths, infrared lamps, or heated wraps. Heat increases blood flow, reduces muscle tone, improves tissue extensibility, and can help prepare trigger-point-affected muscles for stretching and manual treatment.

A hyperirritable spot within a taut band of skeletal muscle that is painful on compression, produces referred pain, and causes motor dysfunction. Trigger points are the defining feature of myofascial pain syndrome and can be active (spontaneously painful) or latent (painful only with palpation). They are the most common cause of regional musculoskeletal pain.

A medical procedure in which a needle is inserted into a trigger point and a substance (local anesthetic, saline, or corticosteroid) is injected. The mechanical disruption from the needle combined with the injected substance helps deactivate the trigger point. The local twitch response during the procedure is associated with better outcomes.

A treatment modality using high-frequency sound waves to generate deep tissue heating and mechanical vibration. Therapeutic ultrasound can increase blood flow, reduce muscle spasm, enhance collagen extensibility, and is sometimes used as an adjunct to manual trigger point treatment.

A postural dysfunction pattern described by Vladimir Janda, characterized by tightness of the upper trapezius, levator scapulae, and pectorals, combined with weakness of the deep neck flexors and lower trapezius. This muscular imbalance is a classic predisposing factor for trigger points in the cervical and shoulder region.

The longest cranial nerve, running from the brainstem through the neck, chest, and abdomen. The vagus nerve is the primary pathway of the parasympathetic (rest-and-digest) nervous system. Vagal tone influences pain modulation, inflammation, and stress response, and can be enhanced through diaphragmatic breathing and other relaxation techniques.

A rapidly evaporating spray (ethyl chloride or fluoromethane) applied to the skin to produce a brief cooling sensation. Vapocoolant sprays are used in the spray-and-stretch technique for trigger point treatment, where the cold stimulus provides a counterirritant effect that allows greater passive muscle stretch.

A reflex in which dysfunction or disease in an internal organ (viscera) causes referred pain, muscle tension, or trigger points in the musculoskeletal system (soma). For example, cardiac disease can produce trigger points in the pectoralis major and left arm muscles, mimicking primary myofascial pain.

The property of biological tissues that exhibit both viscous (fluid-like) and elastic (spring-like) behavior under mechanical loading. Fascia and muscle are viscoelastic, meaning their response to loading depends on the rate and duration of force application, which is why slow sustained stretching is more effective for myofascial release than rapid loading.

A progressive increase in the perceived intensity of repeated identical painful stimuli, caused by temporal summation of nociceptive signals at the spinal cord level. Wind-up is an early manifestation of central sensitization and explains why repetitive activities that mildly irritate a trigger point can produce escalating pain over time.

A structured, goal-oriented rehabilitation program that uses real or simulated work tasks to restore physical function and prepare individuals for return to work. Work hardening programs for myofascial pain progressively increase physical demands while addressing trigger point management, ergonomics, and body mechanics.