The temporomandibular joints (TMJ) are the two joints connecting the jawbone to the skull. It is a bilateral synovial articulation between the temporal bone of the skull above and the mandible below; it is from these bones that its name is derived.

Temporomandibular joint pain is generally due to one of four reasons.

- Myofascial pain dysfunction syndrome, primarily involving the muscles of mastication. This is the most common cause.

- Internal derangements, an abnormal relationship of the disc to any of the other components of the joint. Disc displacement is an example of internal derangement.

- Osteoarthritis of the temporomandibular joint, a degenerative joint disease of the articular surfaces.

- Temporal arteritis, for which it is considered a reliable diagnostic criteria.

Pain or dysfunction of the temporomandibular joint is sometimes referred to as "TMJ", and temporomandibular joint disorder (or "dysfunction") may be abbreviated TMD. This term is used to refer to a group of problems involving the temporomandibular joints and the muscles, tendons, ligaments, blood vessels, and other tissues associated with them.

Although rare, other pathologic conditions may also affect the function of temporomandibular joints, causing pain and swelling. These conditions include chondrosarcoma, osteosarcoma, giant cell tumor and aneurysmal bone cyst.

Generally, degenerative joint changes are associated with greater pain.

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).

Symptoms that may be associated with condylar resorption include:

- Occlusion

- Anterior open bite

- Receding chin

- Clicking or popping when opening or closing the jaw

- Pain when opening or closing the jaw

- Limited jaw mobility

The symptoms can be numerous depending on the severity of the dislocation injury and how long the person is inflicted with the injury. Symptoms of a dislocated jaw include a bite that feels “off” or abnormal, hard time talking or moving jaw, not able to close mouth completely, drooling due to not being able to shut mouth completely, teeth feel they are out of alignment, and a pain that becomes unbearable

The immediate symptom can be a loud crunch noise occurring right up against the ear drum. This is instantly followed by excruciating pain, particularly in the side where the dislocation occurred.

Short-term symptoms can range from mild to chronic headaches, muscle tension or pain in the face, jaw and neck.

Long-term symptoms can result in sleep deprivation, tiredness/lethargy, frustration, bursts of anger or short fuse, difficulty performing everyday tasks, depression, social issues relating to difficulty talking, hearing sensitivity (particularly to high pitched sounds), tinnitus and pain when seated associated with posture while at a computer and reading books from general pressure on the jaw and facial muscles when tilting head down or up. And possible causing subsequent facial asymmetry.

In contrast, symptoms of a fractured jaw include bleeding coming from the mouth, unable to open the mouth wide without pain, bruising and swelling of the face, difficulty eating due to the constant pain, loss of feeling in the face (more specifically the lower lip) and lacks full range of motion of the jaw.

Condylar resorption, also called idiopathic condylar resorption, ICR, and condylysis, is a temporomandibular joint disorder in which one or both of the mandibular condyles are broken down in a bone resorption process. This disorder is nine times more likely to be present in females than males, and is more common among teenagers.

Dislocations occur when two bones that originally met at the joint detach. Dislocations should not be confused with Subluxation. Subluxation is when the joint is still partially attached to the bone.

When a person has a dislocated jaw it is difficult to open and close the mouth. Dislocation can occur following a series of events if the jaw locks while open or unable to close. If the jaw is dislocated, it may cause an extreme headache or inability to concentrate. When the muscle's alignment is out of sync, a pain will occur due to unwanted rotation of the jaw.

If the pain remains constant, it may require surgery to realign the jaw. Depending on the severity of the jaw's dislocation, pain relief such as paracetamol may assist to alleviate the initial chronic pain. If the pain relief is taken for an extended period of time, it may negatively affect the person while talking, eating, drinking, etc.

By far, the two most common symptoms described are pain and the feeling that teeth no longer correctly meet (traumatic malocclusion, or disocclusion). The teeth are very sensitive to pressure (proprioception), so even a small change in the location of the teeth will generate this sensation. People will also be very sensitive to touching the area of the jaw that is broken, or in the case of condylar fracture the area just in front of the tragus of the ear.

Other symptoms may include loose teeth (teeth on either side of the fracture will feel loose because the fracture is mobile), numbness (because the inferior alveolar nerve runs along the jaw and can be compressed by a fracture) and trismus (difficulty opening the mouth).

Outside the mouth, signs of swelling, bruising and deformity can all be seen. Condylar fractures are deep, so it is rare to see significant swelling although, the trauma can cause fracture of the bone on the anterior aspect of the external auditory meatus so bruising or bleeding can sometimes be seen in the ear canal. Mouth opening can be diminished (less than 3 cm). There can be numbness or altered sensation (anesthesia/paraesthesia in the chin and lower lip (the distribution of the mental nerve).

Intraorally, if the fracture occurs in the tooth bearing area, a step may seen between the teeth on either side of the fracture or a space can be seen (often mistaken for a lost tooth) and bleeding from the gingiva in the area. There can be an open bite where the lower teeth, no longer meet the upper teeth. In the case of a unilateral condylar fracture the back teeth on the side of the fracture will meet and the open bite will get progressively greater towards the other side of the mouth.

Sometimes bruising will develop in the floor of the mouth (sublingual eccymosis) and the fracture can be moved by moving either side of the fracture segment up and down. For fractures that occur in the non-tooth bearing area (condyle, ramus, and sometimes the angle) an open bite is an important clinical feature since little else, other than swelling, may be apparent.

This type of fractured mandible can involve one condyle (unilateral) or both (bilateral). Unilateral condylar fracture may cause restricted and painful jaw movement. There may be swelling over the temporomandibular joint region and bleeding from the ear because of lacerations to the external auditory meatus. The hematoma may spread downwards and backwards behind the ear, which may be confused with Battle's sign (a sign of a base of skull fracture), although this is an uncommon finding so if present, intra-cranial injury must be ruled out. If the bones fracture and overlie each other there may be shortening of the height of the ramus. This results in gagging of the teeth on the fractured side (the teeth meet too soon on the fractured side, and not on the non fractured side, i.e. "open bite" that becomes progressively worse to the unaffected side). When the mouth is opened, there may be deviation of the mandible towards the fractured side. Bilateral condylar fractures may cause the above signs and symptoms, but on both sides. Malocclusion and restricted jaw movement are usually more severe. Bilateral body or parasymphysis fractures are sometimes termed "flail mandible", and can cause involuntary posterior movement of the tongue with subsequent obstruction of the upper airway. Displacement of the condyle through the roof of glenoid fossa and into the middle cranial fossa is rare. Bilateral condylar fractures combined with a symphyseal fracture is sometimes termed a guardsman's fracture. The name comes from this injury occurring in soldiers who faint on parade grounds and strike the floor with their chin.

Those with hypermobile joints are more likely to have fibromyalgia, mitral valve prolapse, and anxiety disorders such as panic disorder.

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

Trismus, also called lockjaw, is reduced opening of the jaws (limited jaw range of motion). It may be caused by spasm of the muscles of mastication or a variety of other causes. Temporary trismus occurs much more frequently than permanent trismus. It is known to interfere with eating, speaking, and maintaining proper oral hygiene. This interference, specifically with the patient's ability to swallow properly, results in an increased risk of aspiration. In some instances, trismus presents with altered facial appearance. The condition may be distressing and painful for the patient. Examination and treatments requiring access to the oral cavity can be limited, or in some cases impossible, due to the nature of the condition itself.

Trismus is defined as difficulty in opening the mouth due to a muscle spasm resulting from a disturbance in the trigeminal nerve, however it can also refer to limited mouth opening of any cause. Another definition of trismus is simply a limitation of movement. Historically and commonly, the term "lock jaw" was sometimes used as a synonym for both trismus and tetanus.

Normal mouth-opening ranges from 35 to 45 mm. Males usually have slightly greater mouth opening than females. (40–60 mm, average of 35 mm). The Normal Lateral movement is 8-12mm, and normal protrusive movement is approximately 10mm. Some have distinguished mild trismus as 20–30 mm interincisal opening, moderate as 10–20 mm and severe as less than 10 mm.

Trismus is derived from the Irish word "trismos" meaning "a scream; a grinding, rasping or gnashing"

A bunion is a deformity of the joint connecting the big toe to the foot. The big toe often bends towards the other toes and the joint becomes red and painful. Onset is gradual. Complications may include bursitis or arthritis.

The exact cause is unclear. Proposed factors include wearing overly tight shoes, family history, and rheumatoid arthritis. Diagnosis is generally based on symptoms and supported by X-rays. A similar condition of the little toe is referred to as a bunionette.

Treatment may include proper shoes, orthotics, or NSAIDs. If this is not effective for improving symptoms, surgery may be done. It affects about 23% of adults. Females are affected more often than males. Usual age of onset is between 20 and 50 years old. The condition also becomes more common with age. It was first clearly described in 1870.

The symptoms of bunions include irritated skin around the bunion, pain when walking, joint redness and pain, and possible shift of the big toe toward the other toes. Blisters may form more easily around the site of the bunion as well.

The presence of bunions can lead to difficulties finding properly fitting footwear and may force a person to buy a larger size shoe to accommodate the width the bunion creates. If the bunion deformity becomes severe enough, the foot can hurt in different places even without the constriction of shoes. It is then considered as being a mechanical function problem of the forefoot.

Jaw claudication is pain in the jaw associated with chewing. It is a classic symptom of Giant-cell arteritis, but can be confused with symptoms of Temporomandibular joint disease, Rheumatoid arthritis of the temporomandibular joint, Myasthenia gravis, tumors of the Parotid gland, or occlusion or stenosis of the External carotid artery. The term is derived by analogy from claudication of the leg, where pain is caused by arterial insufficiency.

Some sources list some non-specific signs that may be associated with AFP/AO. These include increased temperature and tenderness of the mucosa in the affected area, which is otherwise normal in every regard.

Patient often reports symptoms of paresthesia, pain, and throbbing. Physical examination may be normal, but hypoesthesia, hyperesthesia, and allodynia may be found.

The features of atypical facial pain can be considered according to the Socrates pain assessment method (see table).

Sometimes dental treatment or surgical procedures in the mouth appear to precede the onset of AFP, or sometimes persons with AFP will blame clinicians for their pain.

Unilateral crossbite involves one side of the arch. The most common cause of unilateral crossbite is a narrow maxillary dental arch. This can happen due to habits such as digit sucking, prolonged use of pacifier or upper airway obstruction. Due to the discrepancy between the maxillary and mandibular arch, neuromuscular guidance of the mandible causes mandible to shift towards the side of the crossbite. This is also known as Functional mandibular shift. This shift can become structural if left untreated for a long time during growth, leading to skeletal asymmetries. Unilateral crossbites can present with following features in a child

- Lower midline deviation to the crossbite side

- Class 2 Subdivision relationships

- Temporomandibular disorders

Ear pain, also known as otalgia , is pain in the ear. Primary ear pain is pain that originates inside the ear. Referred ear pain is pain that originates from outside the ear.

Ear pain is not always associated with ear disease. It may be caused by several other conditions, such as impacted teeth, sinus disease, inflamed tonsils, infections in the nose and pharynx, throat cancer, and occasionally as a sensory aura that precedes a migraine.

Ear pain can be caused by disease in the external or middle ear(because of infection), or inner ear, but the three are indistinguishable in terms of the pain experienced.

External ear pain may be:

- Mechanical: trauma, foreign bodies such as hairs, insects or cotton buds.

- Infective (otitis externa): "Staphylococcus", "Pseudomonas", "Candida", herpes zoster, or viral Myringitis. (See Otitis externa)

Middle ear pain may be:

- Mechanical: barotrauma (often iatrogenic), Eustachian tube obstruction leading to acute otitis media.

- Inflammatory / infective: acute otitis media, mastoiditis.

An anterior crossbite can be referred as negative overjet, and is typical of class III skeletal relations (prognathism).

Pericoronitis may also be chronic or recurrent, with repeated episodes of acute pericoronitis occurring periodically. Chronic pericoronitis may cause few if any symptoms, but some signs are usually visible when the mouth is examined.

Acute pericoronitis (i.e. sudden onset and short lived, but significant, symptoms) is defined as "varying degrees of inflammatory involvement of the pericoronal flap and adjacent structures, as well as by systemic complications." Systemic complications refers to signs and symptoms occurring outside of the mouth, such as fever, malaise or swollen lymph nodes in the neck.