Hypermobility generally results from one or more of the following:

- Abnormally shaped ends of one or more bones at a joint

- A Type 1 collagen or other connective tissue defect (as found in Ehlers-Danlos syndrome, Loeys-Dietz syndrome and Marfan syndrome) resulting in weakened ligaments/ligamentous laxity, muscles and tendons. This same defect also results in weakened bones, which may result in osteoporosis and fractures.

- Abnormal joint proprioception (an impaired ability to locate body parts in space and/or monitor an extended joint)

These abnormalities cause abnormal joint stress, meaning that the joints can wear out, leading to osteoarthritis.

The condition tends to run in families, suggesting a genetic basis for at least some forms of hypermobility. The term "double jointed" is often used to describe hypermobility; however, the name is a misnomer and should not be taken literally, as hypermobile joints are not doubled/extra in any sense.

Most people have hypermobility with no other symptoms. Approximately 5% of the healthy population have one or more hypermobile joints. However, people with "joint hypermobility syndrome" are subject to many difficulties. For example, their joints may be easily injured, be more prone to complete dislocation due to the weakly stabilized joint and they may develop problems from muscle fatigue (as muscles must work harder to compensate for weakness in the ligaments that support the joints). Hypermobility syndrome can lead to chronic pain or even disability in severe cases. Musical instrumentalists with hypermobile fingers may have difficulties when fingers collapse into the finger locking position. Or, conversely, they may display superior abilities due to their increased range of motion for fingering, such as in playing a violin or cello.

Hypermobility may be symptomatic of a serious medical condition, such as Stickler Syndrome, Ehlers-Danlos syndrome, Marfan syndrome, Loeys-Dietz syndrome, rheumatoid arthritis, osteogenesis imperfecta, lupus, polio, Down syndrome, morquio syndrome, cleidocranial dysostosis or myotonia congenita.

Hypermobility has been associated with chronic fatigue syndrome and fibromyalgia. Hypermobility causes physical trauma (in the form of joint dislocations, joint subluxations, joint instability, sprains, etc.). These conditions often, in turn, cause physical and/or emotional trauma and are possible triggers for conditions such as fibromyalgia.

Women with hypermobility may experience particular difficulties when pregnant. During pregnancy, the body releases certain hormones that alter ligament physiology, easing the stretching needed to accommodate fetal growth as well as the birthing process. The combination of hypermobility and pregnancy-related pelvic girdle during pregnancy can be debilitating. The pregnant woman with hypermobile joints will often be in significant pain as muscles and joints adapt to the pregnancy. Pain often inhibits such women from standing or walking during pregnancy. The pregnant patient may be forced to use a bedpan and/or a wheelchair during pregnancy and may experience permanent disability.

Symptoms of hypermobility include a dull but intense pain around the knee and ankle joints and the soles of the feet. The pain and discomfort affecting these body parts can be alleviated by using custom orthoses.

People with Joint Hypermobility Syndrome may develop other conditions caused by their unstable joints. These conditions include:

- Joint instability causing frequent sprains, tendinitis, or bursitis when doing activities that would not affect others

- Joint pain

- Early-onset osteoarthritis (as early as during teen years)

- Subluxations or dislocations, especially in the shoulder (severe limits to ability to push, pull, grasp, finger, reach, etc., is considered a disability by the US Social Security Administration)

- Knee pain

- Fatigue, even after short periods of exercise

- Back pain, prolapsed discs or spondylolisthesis

- Joints that make clicking noises (also a symptom of osteoarthritis)

- Susceptibility to whiplash

- Temporomandibular Joint Syndrome also known as TMJ

- Increased nerve compression disorders (such as carpal tunnel syndrome)

- The ability of finger locking

- Poor response to anaesthetic or pain medication

- "Growing pains" as described in children in late afternoon or night

While ligamentous laxity may be genetic and affect an individual from a very early age, it can also be the result of an injury. Injuries, especially those involving the joints, invariably damage ligaments either by stretching them abnormally or even tearing them.

Loose or lax ligaments in turn are not capable of supporting joints as effectively as healthy ones, making the affected individual prone to further injury as well as compensation for the weakness using other parts of the body. Afflicted individuals may improve over time and lose some of their juvenile hyperlaxity as they age. Individuals over age 40 often have recurrent joint problems and almost always suffer from chronic pain. Back patients with ligamentous laxity in the area of the spine may also experience osteoarthritis and disc degeneration.

In the case of extreme laxity, or hypermobility, affected individuals often have a decreased ability to sense joint position, which can contribute to joint damage. The resulting poor limb positions can lead to the acceleration of degenerative joint conditions. Many hypermobility patients suffer from osteoarthritis, disorders involving nerve compression, chondromalacia patellae, excessive anterior mandibular movement, mitral valve prolapse, uterine prolapse and varicose veins.

Ligamentous laxity, or ligament laxity, means loose ligaments. Ligamentous laxity is a cause of chronic body pain characterized by loose ligaments. When this condition affects joints in the entire body, it is called "generalized joint hypermobility", which occurs in about ten percent of the population, and may be genetic. Loose ligaments can appear in a variety of ways and levels of severity. It also does not always affect the entire body. One could have loose ligaments of the feet, but not of the arms.

Someone with ligamentous laxity, by definition, has loose ligaments. Unlike other, more pervasive diseases, the diagnosis does not require the presence of loose tendons, muscles or blood vessels, hyperlax skin or other connective tissue problems. In heritable connective tissue disorders associated with joint hyper-mobility (such as Marfan syndrome and Ehlers–Danlos syndrome types I–III, VII, and XI), the joint laxity usually is apparent before adulthood. However, age of onset and extent of joint laxity are variable in Marfan syndrome, and joint laxity may be confined to the hands alone, as in Ehlers–Danlos syndrome type IV.

The most common initial symptom of wrist osteoarthritis is joint pain. The pain is brought on by activity and increases when there is activity after resting. Other signs and symptoms, as with any joint affected by osteoarthritis, include:

- Morning stiffness, which usually lasts less than 30 minutes. This is also present in patients with rheumatoid arthritis, but in those patients this typically lasts for more than 45 minutes.

- Swelling of the wrist.

- Crepitus (crackling), which is felt when the hand is moved passively.

- Joint locking, where the joint is fixed in an extended position.

- Joint instability.

These symptoms can lead to loss of function and less daily activity.

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.

The onset of the condition is usually gradual, although some cases may appear suddenly following trauma.

- Knee pain - the most common symptom is diffuse peripatellar pain (vague pain around the kneecap) and localized retropatellar pain (pain focused behind the kneecap). Affected individuals typically have difficulty describing the location of the pain, and may place their hands over the anterior patella or describe a circle around the patella (the "circle sign"). Pain is usually initiated when load is put on the knee extensor mechanism, e.g. ascending or descending stairs or slopes, squatting, kneeling, cycling, running or prolonged sitting with flexed (bent) knees. The latter feature is sometimes termed the "movie sign" or "theatre sign" because individuals might experience pain while sitting to watch a film or similar activity. The pain is typically aching with occasional sharp pains.

- Crepitus (joint noises) may be present

- Giving-way of the knee may be reported

The primary and most common symptom in patients with CMC OA of the thumb is pain. Pain at the base of the thumb is mainly experienced when moving the thumb or when applying pressure with the thumb. However, in advanced stages of CMC OA, pain might persist at rest. Another prominent symptom is loss of strength of the thumb. Patients struggle to grab or hold an object due to weakening of the thumb. For example, tying a knot or holding a saucepan becomes increasingly difficult.

If patients present themselves with similar symptoms, physicians should also consider De Quervain syndrome, rheumatoid arthritis or flexor carpi radialis and flexor pollicis longus tendinopathy as a possible cause.

Typical signs of CMC OA can be observed from the outside of the hand. For example, the area near the base of the thumb can be swollen and could appear inflamed. Advanced stages of CMC OA can eventually lead to deformity of the thumb. This deformity, also called a ‘zigzag’ deformity, is characterized by a deviation of the thenar eminence towards the middle of the hand, whilst the thumb phalanges overextend. Also a grinding sound, known as crepitus, can be heard when the CMC1 joint is moved.

The following factors may be involved in causing this deformity:

- Inherent laxity of the knee ligaments

- Weakness of biceps femoris muscle

- Instability of the knee joint due to ligaments and joint capsule injuries

- Inappropriate alignment of the tibia and femur

- Malunion of the bones around the knee

- Weakness in the hip extensor muscles

- Gastrocnemius muscle weakness (in standing position)

- Upper motor neuron lesion (for example, hemiplegia as the result of a cerebrovascular accident)

- Lower motor neuron lesion (for example, in post-polio syndrome)

- Deficit in joint proprioception

- Lower limb length discrepancy

- Congenital genu recurvatum

- Cerebral palsy

- Multiple sclerosis

- Muscular dystrophy

- Limited dorsiflexion (plantar flexion contracture)

- Popliteus muscle weakness

- Connective tissue disorders. In these disorders, there are excessive joint mobility (joint hypermobility) problems. These disorders include:

- Marfan syndrome

- Ehlers-Danlos syndrome

- Benign hypermobile joint syndrome

- Osteogenesis imperfecta disease

Trapeziometacarpal osteoarthritis, also known as carpometacarpal (CMC) osteoarthritis (OA) of the thumb or osteoarthritis at the base of the thumb, is a reparitive joint disease affecting the first carpometacarpal joint (CMC1). This joint is formed by the trapezium bone of the wrist and the first metacarpal bone of the thumb. Because of its relative instability, this joint is a frequent site for osteoarthritis. Carpometacarpal osteoarthritis (CMC OA) of the thumb occurs when the cushioning cartilage of the joint surfaces wears away, resulting in damage of the joint.

The main complaint of patients is pain. Pain at the base of the thumb occurs when moving the thumb and might eventually persist at rest. Other symptoms include stiffness, swelling and loss of strength of the thumb. Treatment options include conservative and surgical therapies.

The clinical presentation varies depending on the stage of the disease from mild swelling to severe swelling and moderate deformity. Inflammation, erythema, pain and increased skin temperature (3–7 degrees Celsius) around the joint may be noticeable on examination. X-rays may reveal bone resorption and degenerative changes in the joint. These findings in the presence of intact skin and loss of protective sensation are pathognomonic of acute Charcot arthropathy.

Roughly 75% of patients experience pain, but it is less than what would be expected based on the severity of the clinical and radiographic findings.

Osteoarthritis of the wrist is predominantly a clinical diagnosis, and thus is primarily based on the patients medical history, physical examination and wrist X-rays.

Genu recurvatum is a deformity in the knee joint, so that the knee bends backwards. In this deformity, excessive extension occurs in the tibiofemoral joint. Genu recurvatum is also called knee hyperextension and back knee. This deformity is more common in women and people with familial ligamentous laxity. Hyperextension of the knee may be mild, moderate or severe.

The normal range of motion (ROM) of the knee joint is from 0 to 135 degrees in an adult. Full knee extension should be no more than 10 degrees. In genu recurvatum (back knee), normal extension is increased. The development of genu recurvatum may lead to knee pain and knee osteoarthritis.

Joint stiffness may be either the symptom of pain on moving a joint, the symptom of loss of range of motion or the physical sign of reduced range of motion.

- Pain on movement is commonly caused by osteoarthritis, often in quite minor degrees, and other forms of arthritis. It may also be caused by injury or overuse and rarely by more complex causes of pain such as infection or neoplasm. The range of motion may be normal or limited by pain. "Morning stiffness" pain which eases up after the joint has been used, is characteristic of rheumatoid arthritis.

- Loss of motion (symptom): the patient notices that the joint (or many joints) do not move as far as they used to or need to. Loss of motion is a feature of more advanced stages of arthritis including osteoarthritis, rheumatoid arthritis and ankylosing spondylitis.

- Loss of range of motion (sign): the examining medical professional notes that the range of motion of the joint is less than normal. Routine examination by an orthopaedic surgeon or rheumatologist will often pay particular attention to this. The range of motion may be measured and compared to the other side and to normal ranges. This sign is associated with the same causes as the symptom. In extreme cases when the joint does not move at all it is said to be ankylosed.

Facet syndrome (also commonly known as facet joint disease, facet osteoarthritis, facet hypertrophy or facet arthritis) is a syndrome in which the facet joints (synovial diarthroses, from C2 to S1) degenerate to the point of causing painful symptoms. In conjunction with degenerative disc disease, a distinct but functionally related condition, facet syndrome is believed to be one of the most common causes of lower back pain.

Chondromalacia patellae is a term sometimes treated synonymously with PFPS. However, there is general consensus that PFPS applies only to individuals without cartilage damage, thereby distinguishing it from chondromalacia patellae, a condition characterized by softening of the patellar articular cartilage. Despite this academic distinction, the diagnosis of PFPS is typically made clinically, based only on the history and physical examination rather than on the results of any medical imaging. Therefore, it is unknown whether most persons with a diagnosis of PFPS have cartilage damage or not, making the difference between PFPS and chondromalacia theoretical rather than practical. It is thought that only some individuals with anterior knee pain will have true chondromalacia patellae.

A combination of postural changes, the growing baby, unstable pelvic joints under the influence of pregnancy hormones, and changes in the centre of gravity can all add to the varying degrees of pain or discomfort. In some cases it can come on suddenly or following a fall, sudden abduction of the thighs (opening too wide too quickly) or an action that has strained the joint.

PGP can begin as early as the first trimester of pregnancy. Pain is usually felt low down over the symphyseal joint, and this area may be extremely tender to the touch. Pain may also be felt in the hips, groin and lower abdomen and can radiate down the inner thighs. Women suffering from PGP may begin to waddle or shuffle, and may be aware of an audible clicking sound coming from the pelvis. PGP can develop slowly during pregnancy, gradually gaining in severity as the pregnancy progresses.

During pregnancy and postpartum, the symphyseal gap can be felt moving or straining when walking, climbing stairs or turning over in bed; these activities can be difficult or even impossible. The pain may remain static, e.g., in one place such as the front of the pelvis, producing the feeling of having been kicked; in other cases it may start in one area and move to other areas. It is also possible that a woman may experience a combination of symptoms.

Any weight bearing activity has the potential of aggravating an already unstable pelvis, producing symptoms that may limit the ability of the woman to carry out many daily activities. She may experience pain involving movements such as dressing, getting in and out of the bath, rolling in bed, climbing the stairs or sexual activity. Pain may also be present when lifting, carrying, pushing or pulling.

The symptoms (and their severity) experienced by women with PGP vary, but include:

- Present swelling and/or inflammation over joint.

- Difficulty lifting leg.

- Pain pulling legs apart.

- Inability to stand on one leg.

- Inability to transfer weight through pelvis and legs.

- Pain in hips and/or restriction of hip movement.

- Transferred nerve pain down leg.

- Can be associated with bladder and/or bowel dysfunction.

- A feeling of the symphysis pubis giving way.

- Stooped back when standing.

- Malalignment of pelvic and/or back joints.

- Struggle to sit or stand.

- Pain may also radiate down the inner thighs.

- Waddling or shuffling gait.

- Audible ‘clicking’ sound coming from the pelvis.

Common deformities of the knee include:

- Genu varum

- Genu valgum

- Genu recurvatum (Knee hyperextension)

- Knee flexion deformity

- Bipartite patella

Shoulder problems including pain, are one of the more common reasons for physician visits for musculoskeletal symptoms. The shoulder is the most movable joint in the body. However, it is an unstable joint because of the range of motion allowed. This instability increases the likelihood of joint injury, often leading to a degenerative process in which tissues break down and no longer function well.

Shoulder pain may be localized or may be referred to areas around the shoulder or down the arm. Other regions within the body (such as gallbladder, liver, or heart disease, or disease of the cervical spine of the neck) also may generate pain that the brain may interpret as arising from the shoulder.

Higher numbers indicate a more severe problem and greater likelihood of a poor final outcome.

Neuropathic arthropathy (or neuropathic osteoarthropathy), also known as Charcot joint (often "Charcot foot"), refers to progressive degeneration of a weight bearing joint, a process marked by bony destruction, bone resorption, and eventual deformity due to loss of sensation. Onset is usually insidious.

If this pathological process continues unchecked, it can result in joint deformity, ulceration and/or superinfection, loss of function, and in the worst-case scenario, amputation or death. Early identification of joint changes is the best way to limit morbidity.

This flexion deformity of the proximal interphalangeal joint is due to interruption of the central slip of the extensor tendon such that the lateral slips separate and the head of the proximal phalanx pops through the gap like a finger through a button hole (thus the name, from French "boutonnière" "button hole"). The distal joint is subsequently drawn into hyperextension because the two peripheral slips of the extensor tendon are stretched by the head of the proximal phalanx (note that the two peripheral slips are inserted into the distal phalanx, while the proximal slip is inserted into the middle phalanx). This deformity makes it difficult or impossible to extend the proximal interphalangeal joint.

One knee may appear larger than the other. Puffiness around the bony parts of the knee appear prominent when compared with the other knee.

Osteoarthritis knee pain usually occurs while the joint is bearing weight, so the pain typically subsides with rest; some patients suffer severe pain, while others report no discomfort. Even if one knee is much larger than the other, pain is not guaranteed.

Referred pain is that pain perceived at a site different from its point of origin but innervated by the same spinal segment. Sometimes knee pain may be related to another area from body. For example, knee pain can come from ankle, foot, hip joints or lumbar spine.