Myofascial pain is pain in muscles or fascia (a type of connective tissue that surrounds muscles). It can occur in distinct, isolated areas of the body. Because any muscle or fascia in the body may be affected, this may cause a variety of localized symptoms.

Generally speaking, the muscular pain is steady, aching, and deep. Depending on the case and location the intensity can range from mild discomfort to excruciating and "lightning-like".

LA SKIN'S DIAGNOSTIC CRITERIA:

- Unilateral pain

- Muscle tenderness

- Clicking sound

- Limitations in jaw function

Knots may be visible or felt beneath the skin. The pain does not resolve on its own, even after typical first-aid self-care such as ice, heat, and rest.

Signs and symptoms of temporomandibular joint disorder vary in their presentation. The symptoms will usually involve more than one of the various components of the masticatory system, muscles, nerves, tendons, ligaments, bones, connective tissue, or the teeth.

The three classically described, cardinal signs and symptoms of TMD are:

- Pain and tenderness on palpation in the muscles of mastication, or of the joint itself (preauricular pain – pain felt just in front of the ear). Pain is the defining feature of TMD and is usually aggravated by manipulation or function, such as when chewing, clenching, or yawning, and is often worse upon waking. The character of the pain is usually dull or aching, poorly localized, and intermittent, although it can sometimes be constant. The pain is more usually unilateral (located on one side) rather than bilateral. It is rarely severe.

- Limited range of mandibular movement, which may cause difficulty eating or even talking. There may be locking of the jaw, or stiffness in the jaw muscles and the joints, especially present upon waking. There may also be incoordination, asymmetry or deviation of mandibular movement.

- Noises from the joint during mandibular movement, which may be intermittent. Joint noises may be described as clicking, popping, or crepitus (grating).

Other signs and symptoms have also been described, although these are less common and less significant than the cardinal signs and symptoms listed above. Examples include:

- Headache (possibly), e.g. pain in the occipital region (the back of the head), or the forehead; or other types of facial pain including migraine, tension headache. or myofascial pain.

- Pain elsewhere, such as the teeth or neck.

- Diminished auditory acuity (hearing loss).

- Tinnitus (occasionally).

- Dizziness.

- Sensation of malocclusion (feeling that the teeth do not meet together properly).

Sometimes distinction is made between acute TMD, where symptoms last for less than 3 months, and chronic TMD, where symptoms last for more than 3 months. Not much is known about acute TMD since these individuals do not typically attend in secondary care (hospital).

Myofascial pain syndrome (MPS), also known as chronic myofascial pain (CMP), is a syndrome characterized by chronic pain in multiple myofascial trigger points ("knots") and fascial (connective tissue) constrictions. It can appear in any body part.

Characteristic features of a myofascial trigger points include: focal point tenderness, reproduction of pain upon trigger point palpation, hardening of the muscle upon trigger point palpation, pseudo-weakness of the involved muscle, referred pain, and limited range of motion following approximately 5 seconds of sustained trigger point pressure.

Pain or tenderness to palpation usually occurs on the sides of the sternum, affects multiple ribs, and is often worsened with coughing, deep breathing, or physical activity. On physical examination, a physician inspects and feels the patient for swollen or tender areas, and can often produce the pain of costochondritis by moving the patient's rib cage or arms.

A factor that may aid in the differentiation of costochondritis from Tietze syndrome is the location of the pain on the sternum. Costochondritis typically affects the third, fourth, and fifth costosternal joints in contrast to Tietze's syndrome, which usually affects the second or third costosternal joint. Pain from costochondritis typically resolves within one year.

Clinical features of CRPS have been found to be inflammation resulting from the release of certain pro-inflammatory chemical signals from the nerves, sensitized nerve receptors that send pain signals to the brain, dysfunction of the local blood vessels' ability to constrict and dilate appropriately, and maladaptive neuroplasticity.

The signs and symptoms of CRPS usually initially manifest near the site of a (typically minor) injury. The most common symptoms are pain sensations, including burning, stabbing, grinding, and throbbing. Moving or touching the limb is often intolerable. The patient may also experience muscle spasms; local swelling; extreme sensitivity to things such as wind and water, touch and vibrations; abnormally increased sweating; changes in skin temperature (usually hot but sometimes cold) and color (bright red or a reddish violet); softening and thinning of bones; joint tenderness or stiffness; changes in nail and hair growth and/or restricted or painful movement. Drop attacks (falls), almost fainting, and fainting spells are infrequently reported, as are visual problems. The symptoms of CRPS vary in severity and duration. Since CRPS is a systemic problem, potentially any organ can be affected.

The pain of CRPS is continuous although varies in severity. It is widely recognized that it can be heightened by emotional or physical stress.

Previously it was considered that CRPS had three stages; it is now believed that people affected by CRPS do not progress through these stages sequentially. These stages may not be time-constrained and could possibly be event-related, such as ground-level falls or re-injuries of previously damaged areas. Thus, rather than a progression of CRPS from bad to worse, it is now thought, instead, that such individuals are likely to have one of the three following types of disease progression:

1. "Stage" one is characterized by severe, burning pain at the site of the injury, muscle spasms, joint stiffness, restricted mobility, rapid hair and nail growth, and vasospasm. The vasospasm is that which causes the changes in the color and temperature of the skin. Some may experience hyperhydrosis (increased sweating). In mild cases this stage lasts a few weeks, in which it can subside spontaneously or respond rapidly to treatment (physical therapy, pain specialist).

2. "Stage" two is characterized by more intense pain. Swelling spreads, hair growth diminishes, nails become cracked, brittle, grooved and spotty, osteoporosis becomes severe and diffuse, joints thicken, and muscles atrophy.

3. "Stage" three is characterized by irreversible changes in the skin and bones, while the pain becomes unyielding and may involve the entire limb. There is marked muscle atrophy, severely limited mobility of the affected area, and flexor tendon contractions (contractions of the muscles and tendons that flex the joints). Occasionally the limb is displaced from its normal position, and marked bone softening and thinning is more dispersed.

Costochondritis, also known as chest wall pain, costosternal syndrome, or costosternal chondrodynia is an acute and often temporary inflammation of the costal cartilage, the structure that connects each rib to the sternum at the costosternal joint. The condition is a common cause of chest pain. Though costochondritis often resolves on its own, it can be a recurring condition that has little or no signs of onset.

Costochondritis symptoms can be similar to the chest pain associated with a heart attack. Chest pain is considered a medical emergency until life-threatening cardiac issues can be ruled out. Severe cases of costal cartilage inflammation that also involve painful swelling are sometimes referred to as Tietze's syndrome, a term sometimes used interchangeably with costochondritis. However, some physicians view costochondritis and Tietze's syndrome as separate disease states due to the absence of costal cartilage swelling in costochondritis.

Treatment options are quite limited and usually involve a combination of rest, analgesics, or anti-inflammatory medications. Cases with persistent discomfort may be managed with cortisone injections or surgery may be indicated if the condition is severe. Individuals with costochondritis are typically instructed to avoid strenuous physical activity to prevent the onset of an attack.

Complex regional pain syndrome (CRPS), also known as reflex sympathetic dystrophy (RSD), is a long term pain syndrome that often worsens with time. It is characterized by severe pain out of proportion to the original injury and is often accompanied by sensitivity, swelling, and changes in the skin. It may initially affect one limb and then spread throughout the body; 35% of affected people report symptoms throughout their whole body.

The cause of CRPS is unknown though CRPS is associated with dysregulation of the central nervous system and autonomic nervous system resulting in abnormal temperature control and pain of the affected limb(s) resulting in functional impairment and disability. Precipitating factors include injury and surgery, although there are cases where no identifiable injury had occurred at the original site. CRPS is not caused by psychological factors, yet the constant pain and reduced quality of life are known to cause psychological problems (such as increased depression and anxiety). Although "research does not reveal support for specific personality or psychopathology predictors of the condition," CRPS is associated with psychosocial effects, including impaired social and occupational function. It is classified as an amplified musculoskeletal pain syndrome.

Treatment involves a multidisciplinary approach involving medications, physical and occupational therapy, psychological treatments, and neuromodulation. Despite this, the results are often unsatisfactory, especially if treatment is delayed.

Meralgia paresthetica or meralgia paraesthetica (or Bernhardt-Roth syndrome), is numbness or pain in the outer thigh not caused by injury to the thigh, but by injury to a nerve that extends from the spinal column to the thigh.

This chronic neurological disorder involves a single nerve—the lateral cutaneous nerve of thigh, which is also called the lateral femoral cutaneous nerve (and hence the syndrome lateral femoral cutaneous neuropathy). The term "meralgia paraesthetica" combines four Greek roots to mean "thigh pain with anomalous perception". The disorder has also been nicknamed skinny pants syndrome, in reference to a rise in teenagers wearing skin-tight pants.

Affected individuals typically experience limited relief from standard pain relieving medication, with the exception of some neuroleptic agents. Patients frequently experience 'pseudovisceral' phenomena or symptoms of altered autonomic nervous system function including nausea, bloating, abdominal swelling, loss of appetite with consecutively lowered body weight or an altered defecation process.

Pain is typically related to tensing the abdominal wall muscles, so any type of movement is prone to aggravate pain. Lying quietly can be the least painful position. Most patients report that they cannot sleep on the painful side.

The entire distribution of the nerve is rarely affected. Usually, the unpleasant sensation(s) affect only part of the skin supplied by the nerve.

Chronic fatigue syndrome a.k.a. Myalgic Encephalomyelitis, Channelopathy, Ehlers Danlos Syndrome, Stickler Syndrome, Hypokalemia, Hypotonia (Low Muscle Tone), Exercise intolerance, Mastocytosis, Peripheral neuropathy, Eosinophilia myalgia syndrome, Barcoo Fever, Herpes, Hemochromatosis a.k.a. Iron Overload Disorder, Delayed onset muscle soreness, AIDS, HIV, Tumor-induced osteomalacia, Hypovitaminosis D, infarction

Anterior cutaneous nerve entrapment syndrome (ACNES) is a nerve entrapment condition that causes chronic pain of the abdominal wall. It occurs when nerve endings of the lower thoracic intercostal nerves (7–12) are 'entrapped' in abdominal muscles, causing a severe localized nerve (neuropathic) pain that is usually experienced at the front of the abdomen.

ACNES syndrome is frequently overlooked and unrecognized, although the incidence is estimated to be 1:2000 patients.

The relative unfamiliarity with this condition often leads to significant diagnostic delays and misdiagnoses, often resulting in unnecessary diagnostic interventions and futile procedures. Physicians often misdiagnose ACNES as irritable bowel syndrome or "functional disorders", as symptoms of the condition are not dispositive.

The most common causes of myalgia are overuse, injury or strain. However, myalgia can also be caused by diseases, disorders, medications, or as a response to a vaccination. It is also a sign of acute rejection after heart transplant surgery.

The most common causes are:

There are no specific clinical signs or complementary test results for this condition. The typical symptoms of PNE or PN are seen, for example, in male competitive cyclists (it is often called "cyclist syndrome"), who can rarely develop recurrent numbness of the penis and scrotum after prolonged cycling, or an altered sensation of ejaculation, with disturbance of micturition (urination) and reduced awareness of defecation. Nerve entrapment syndromes, presenting as genitalia numbness, are amongst the most common bicycling associated urogenital problems.

The pain is typically caused by sitting, relieved by standing, and is absent when recumbent (lying down) or sitting on a toilet seat. If the perineal pain is positional (changes with the patient's position, for example sitting or standing), this suggests a tunnel syndrome. Anesthesiologist John S. McDonald of UCLA reports that sitting pain relieved by standing or sitting on a toilet seat is the most reliable diagnostic parameter.

Other than positional pain and numbness, the main symptoms are fecal incontinence and urinary incontinence.

Differential diagnosis should consider the far commoner conditions chronic prostatitis/chronic pelvic pain syndrome and interstitial cystitis.

The primary symptom is hip pain, especially hip pain on the outer (lateral) side of the joint. This pain may appear when the affected person is walking or lying down on that side.

The main presentation of the syndrome is significant, acute pain in the chest, along with tenderness and some swelling of the cartilages affected, which is commonly palpable on examination. Perceived pain is often exacerbated with respiration. Although many times it can be extremely painful, to the point of being debilitating, Tietze's syndrome is considered to be a benign condition that generally resolves in 12 weeks. However, it can often be a chronic condition.

The associated chest pain may present similarly to angina pectoris, normally associated with heart disease, and can cause hyperventilation, anxiety or panic attacks, syncope (passing out), and temporary hypoesthesia (numbness) or paralysis.

Many cases of myocardial infarction (heart attack) patients have been re-considered and improperly diagnosed, due to the identical nature of the symptoms. In females, it is often misdiagnosed as mastalgia. Costochondritis symptoms are similar to Tietze's, the prime difference being that the pain radiates to the arms and shoulders in the latter.

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is characterized by pelvic or perineal pain without evidence of urinary tract infection, lasting longer than 3 months, as the key symptom. Symptoms may wax and wane. Pain can range from mild to debilitating. Pain may radiate to the back and rectum, making sitting uncomfortable. Pain can be present in the perineum, testicles, tip of penis, pubic or bladder area. Dysuria, arthralgia, myalgia, unexplained fatigue, abdominal pain, constant burning pain in the penis, and frequency may all be present. Frequent urination and increased urgency may suggest interstitial cystitis (inflammation centred in bladder rather than prostate). Post-ejaculatory pain, mediated by nerves and muscles, is a hallmark of the condition, and serves to distinguish CP/CPPS patients from men with BPH or normal men. Some patients report low libido, sexual dysfunction and erectile difficulties.

Some of the symptoms are:

- Pain and tingling in and around ankles and sometimes the toes

- Swelling of the feet

- Painful burning, tingling, or numb sensations in the lower legs. Pain worsens and spreads after standing for long periods; pain is worse with activity and is relieved by rest.

- Electric shock sensations

- Pain radiating up into the leg, and down into the arch, heel, and toes

- Hot and cold sensations in the feet

- A feeling as though the feet do not have enough padding

- Pain while operating automobiles

- Pain along the Posterior Tibial nerve path

- Burning sensation on the bottom of foot that radiates upward reaching the knee

- "Pins and needles"-type feeling and increased sensation on the feet

- A positive Tinel's sign

Tinel's sign is a tingling electric shock sensation that occurs when you tap over an affected nerve. The sensation usually travels into the foot but can also travel up the inner leg as well.

Greater trochanteric pain syndrome (GTPS), also known as trochanteric bursitis, is inflammation of the trochanteric bursa, a part of the hip.

This bursa is at the top, outer side of the femur, between the insertion of the gluteus medius and gluteus minimus muscles into the greater trochanter of the femur and the femoral shaft. It has the function, in common with other bursae, of working as a shock absorber and as a lubricant for the movement of the muscles adjacent to it.

Occasionally, this bursa can become inflamed and clinically painful and tender. This condition can be a manifestation of an injury (often resulting from a twisting motion or from overuse), but sometimes arises for no obviously definable cause. The symptoms are pain in the hip region on walking, and tenderness over the upper part of the femur, which may result in the inability to lie in comfort on the affected side.

More often the lateral hip pain is caused by disease of the gluteal tendons that secondarily inflames the bursa. This is most common in middle-aged women and is associated with a chronic and debilitating pain which does not respond to conservative treatment. Other causes of trochanteric bursitis include uneven leg length, iliotibial band syndrome, and weakness of the hip abductor muscles.

Greater trochanteric pain syndrome can remain incorrectly diagnosed for years, because it shares the same pattern of pain with many other musculoskeletal conditions. Thus people with this condition may be labeled malingerers, or may undergo many ineffective treatments due to misdiagnosis. It may also coexist with low back pain, arthritis, and obesity.

Any of the aforementioned pain conditions/syndromes can persist for years after vasectomy and affect as many as one in three vasectomized men. The range of PVPS pain can be mild/annoying to the less-likely extreme debilitating pain experienced by a smaller number of sufferers in this group. There is a continuum of pain severity between these two extremes. Pain is thought to be caused by any of the following, either singularly or in combination: testicular backpressure, overfull epididymides, chronic inflammation, fibrosis, sperm granulomas, and nerve entrapment. Pain can be present continuously in the form of orchialgia and/or congestive epididymitis or it can be situational, such as pain during intercourse, ejaculation or physical exertion.

Pudendal nerve entrapment (PNE), also known as Alcock canal syndrome, is an uncommon source of chronic pain, in which the pudendal nerve (located in the pelvis) is entrapped or compressed. Pain is positional and is worsened by sitting. Other symptoms include genital numbness, fecal incontinence and urinary incontinence.

The term pudendal neuralgia (PN) is used interchangeably with "pudendal nerve entrapment", but a 2009 review study found both that "prevalence of PN is unknown and it seems to be a rare event" and that "there is no evidence to support equating the presence of this syndrome with a diagnosis of pudendal nerve entrapment," meaning that it is possible to have all the symptoms of pudendal nerve entrapment (otherwise known as pudendal neuralgia) based on the criteria specified at Nantes in 2006, without having an entrapped pudendal nerve.

A 2015 study of 13 normal female cadavers found that the pudendal nerve was attached or fixed to the sacrospinous ligament in all cadavers studied, suggesting that the diagnosis of pudendal nerve entrapment may be overestimated.

A 2016 review paper found that although the peripheral nervous system is responsible for starting the condition, the central nervous system (CNS) is responsible for continuing the pain even without continuing input from the peripheral nerves.

Post-vasectomy pain syndrome is a chronic and sometimes debilitating genital pain condition that may develop immediately or several years after vasectomy. Because this condition is a syndrome, there is no single treatment method, therefore efforts focus on mitigating/relieving the individual patient's specific pain. When pain in the epididymides is the primary symptom, post-vasectomy pain syndrome is often described as congestive epididymitis.

The symptoms of facet joint syndrome depend almost entirely on the location of the degenerated joint, the severity of the damage and the amount of pressure that is being placed on the surrounding nerve roots. It's important to note that the amount of pain a person experiences does not correlate well with the amount of degeneration that has occurred within the joint. Many people experience little or no pain while others, with the exact same amount of damage, undergo chronic pain.

Additionally, in symptomatic facet syndrome the location of the degenerated joint plays a significant role in the symptoms that are experienced. People with degenerated joints in the upper spine will often feel pain radiating throughout the upper neck and shoulders. That said, symptoms primarily manifest themselves in the lumbar spine, since the strain is highest here due to the overlying body weight and the strong mobility. Affected persons usually feel dull pain in the cervical or lumbar spine that can radiate into the buttocks and legs. Typically, the pain is worsened by stress on the facet joints, e.g. by diffraction into hollow back (retroflexion) or lateral flexion but also by prolonged standing or walking.

Pain associated with facet syndrome is often called "referred pain" because symptoms do not follow a specific nerve root pattern and the brain can have difficulty localizing the specific area of the spine that is affected. This is why patients experiencing symptomatic facet syndrome can feel pain in their shoulders, legs and even manifested in the form of headaches.