DISH is diagnosed by findings on x-ray studies. Radiographs of the spine will show abnormal bone formation (ossification) along the anterior spinal ligament. The disc spaces, facet and sacroiliac joints remain unaffected. Diagnosis requires confluent ossification of at least four contiguous vertebral bodies. Classically, advanced disease may have "melted candle wax" appearance along the spine on radiographic studies. In some cases, DISH may be manifested as ossification of enthesis in other parts of the skeleton.

The calcification and ossification is most common on the right side of the spine. In people with dextrocardia and situs inversus this calcification occurs on the left side, which confirms the role of the descending thoracic aorta in preventing the physical manifestations of DISH on one side of the spine.

Computed tomography is the most sensitive and specific of the imaging techniques. The facial bones can be visualized as slices through the skeletal in either the axial, coronal or sagittal planes. Images can be reconstructed into a 3-dimensional view, to give a better sense of the displacement of various fragments. 3D reconstruction, however, can mask smaller fractures owing to volume averaging, scatter artifact and surrounding structures simply blocking the view of underlying areas.

Research has shown that panoramic radiography is similar to computed tomography in its diagnostic accuracy for mandible fractures and both are more accurate than plain film radiograph. The indications to use CT for mandible fracture vary by region, but it does not seem to add to diagnosis or treatment planning except for comminuted or avulsive type fractures, although, there is better clinician agreement on the location and absence of fractures with CT compared to panoramic radiography.

There are various classification systems of mandibular fractures in use.

Manipulative physiotherapy, therapeutic exercises and chiropractic manipulative therapy shows beneficial results for decreasing pain and increasing spinal range of motion. As areas of the spine and tendons can become inflamed NSAIDs such as ibuprofen and Naproxen can be helpful in both relieving pain and inflammation associated with DISH. It is hoped that by minimizing inflammation in these areas, further calcification of tendons and ligaments of the spine leading to bony outgrowths (enthesophytes) will be prevented, although causative factors are still unknown.

Fibrous ankylosis is a fibrous connective tissue process which results in decreased range of motion. Symptoms present as bony ankylosis, in which osseous tissue fuses two bones together reducing mobility, which is why fibrous ankylosis is also known as false ankylosis.

Pathology may be the result of trauma, disease, chronic inflammation, or surgery.

Some research suggests fibrous ankylosis may precede the development of bony ankylosis

Ankylosis or anchylosis (from Greek ἀγκύλος, bent, crooked) is a stiffness of a joint due to abnormal adhesion and rigidity of the bones of the joint, which may be the result of injury or disease. The rigidity may be complete or partial and may be due to inflammation of the tendinous or muscular structures outside the joint or of the tissues of the joint itself.

When the structures outside the joint are affected, the term "false ankylosis" has been used in contradistinction to "true ankylosis", in which the disease is within the joint. When inflammation has caused the joint-ends of the bones to be fused together, the ankylosis is termed "osseous" or complete and is an instance of synostosis. Excision of a completely ankylosed shoulder or elbow may restore free mobility and usefulness to the limb. "Ankylosis" is also used as an anatomical term, bones being said to ankylose (or anchylose) when, from being originally distinct, they coalesce, or become so joined together that no motion can take place between them.

In 2014, there was a rare case of Ankylosis, wherein a six-year old girl was able to open her mouth only a couple millimeters after one of her jaw joints got fused. Liliana Cernecca was the patient's name. She underwent a surgery at King's College Hospital in London, during which her jaw was operated on and unlocked.She was said to be one of the youngest patients to have undergone this surgery.

Evidence for ankylosis found in the fossil record is studied by paleopathologists, specialists in ancient disease and injury. Ankylosis has been reported in dinosaur fossils from several species, including "Allosaurus fragilis", "Becklespinax altispinax", "Poekilopleuron bucklandii", and "Tyrannosaurus rex" (including the Stan specimen).

Various diagnostic systems have been described. Some consider the Research Diagnostic Criteria method the gold standard. Abbreviated to "RDC/TMD", this was first introduced in 1992 by Dworkin and LeResche in an attempt to classify temporomandibular disorders by etiology and apply universal standards for research into TMD. This method involves 2 diagnostic axes, namely axis I, the physical diagnosis, and axis II, the psychologic diagnosis. Axis I contains 3 different groups which can occur in combinations of 2 or all 3 groups, (see table).

McNeill 1997 described TMD diagnostic criteria as follows:

- Pain in muscles of mastication, the TMJ, or the periauricular area (around the ear), which is usually made worse by manipulation or function.

- Asymmetric mandibular movement with or without clicking.

- Limitation of mandibular movements.

- Pain present for a minimum of 3 months.

The International Headache Society's diagnostic criteria for "headache or facial pain attributed to temporomandibular joint disorder" is similar to the above:

- A. Recurrent pain in one or more regions of the head or face fulfilling criteria C and D

- B. X-ray, MRI or bone scintigraphy demonstrate TMJ disorder

- C. Evidence that pain can be attributed to the TMJ disorder, based on at least one of the following:

- pain is precipitated by jaw movements or chewing of hard or tough food

- reduced range of or irregular jaw opening

- noise from one or both TMJs during jaw movements

- tenderness of the joint capsule(s) of one or both TMJs

- D. Headache resolves within 3 months, and does not recur, after successful treatment of the TMJ disorder

Synostosis (plural: synostoses) is fusion of two bones. It can be normal in puberty, fusion of the epiphysis, or abnormal. When synostosis is abnormal it is a type of dysostosis.

Examples of synostoses include:

- craniosynostosis – an abnormal fusion of two or more cranial bones;

- radioulnar synostosis – the abnormal fusion of the radius and ulna bones of the forearm;

- tarsal coalition – a failure to separately form all seven bones of the tarsus (the hind part of the foot) resulting in an amalgamation of two bones; and

- syndactyly – the abnormal fusion of neighboring digits.

Synostosis within joints can cause ankylosis.

Pain is the most common reason for people with TMD to seek medical advice.

Joint noises may require auscultation with a stethoscope to detect. Clicks of the joint may also be palpated, over the joint itself in the preauricular region, or via a finger inserted in the external acoustic meatus, which lies directly behind the TMJ.

The differential diagnosis is with degenerative joint disease (e.g. osteoarthritis), rheumatoid arthritis, temporal arteritis, otitis media, parotitis, mandibular osteomyelitis, Eagle syndrome, trigeminal neuralgia, oromandibular dystonia, deafferentation pains, and psychogenic pain.

Radioulnar synostosis is one of the more common failures of separation of parts of the upper limb. There are two general types: one is characterized by fusion of the radius and ulna at their proximal borders and the other is fused distal to the proximal radial epiphysis. Most cases are sporadic, congenital (due to a defect in longitudinal segmentation at the 7th week of development) and less often post-traumatic, bilateral in 60%, and more common in males. Familial cases in association with autosomal dominant transmission appear to be concentrated in certain geographic regions, such as Sicily.

The condition frequently is not noted until late childhood, as function may be normal, especially in unilateral cases. Increased wrist motion may compensate for the absent forearm motion. It has been suggested that individuals whose forearms are fixed in greater amounts of pronation (over 60 degrees) face more problems with function than those with around 20 degrees of fixation. Pain is generally not a problem, unless radial head dislocation should occur.

Most examples of radioulnar synostosis are isolated (non-syndromic). Syndromes that may be accompanied by radioulnar synostosis include X chromosome polyploidy (e.g., XXXY) and other chromosome disorders (e.g., 4p- syndrome, Williams syndrome), acrofacial dysostosis, Antley–Bixler syndrome, genitopatellar syndrome, Greig cephalopolysyndactyly syndrome, hereditary multiple osteochondromas (hereditary multiple exostoses), limb-body wall complex, and Nievergelt syndrome.

Craniosynostosis (from cranio, cranium; + syn, together; + ostosis relating to bone) is a condition in which one or more of the fibrous sutures in an infant skull prematurely fuses by turning into bone (ossification). Craniosynostosis has following kinds: scaphocephaly, trigonocephaly, plagiocephaly, anterior plagiocephaly, posterior plagiocephaly, brachycephaly, oxycephaly, pansynostosis.

Tooth ankylosis refers to a fusion (ankylosis) of teeth to bone. The condition is diagnosed with radiographs (X-rays), which show loss of the periodontal ligament space and blending of the root with the bone. Clinically the tooth sounds solid when percussed (tapped) compared to the dull, cushioned sound from normal teeth. Ankylosis of teeth is uncommon, more so in deciduous teeth than permanent teeth.

Repair with cementum or dentin occurs after partial root resorption, fusing the tooth with the bone. It may occur following dental trauma, especially occlusal trauma, or after periapical periodontitis caused by pulp necrosis. Ankylosis itself is not a reason to remove a permanent tooth, however teeth which must be removed for other reasons are made significantly more difficult to remove if they are ankylosed.

Management of teeth with PFE can include extractions of affected teeth, followed by orthodontic space closure or placement of a prosthetic implant with a bone graft. This option can only be applied to a single tooth that is affected. If multiple teeth are affected then, a segmental osteotomy may be performed to bring the entire segment into occlusion. However, minimal success has been shown following this procedure. These teeth usually are "non-responsive" to the orthodontic force and studies have shown that ankylosis of these teeth can occur if force applied.

The best method for the prevention of knocked-out teeth is the use of helmets and mouth protectors. Mouth protectors can be very inexpensive, however, the compliance rate for their use is poor. Studies have shown that, even when mandated, athletes and other high risk individuals often will not use them. Also, even with their use, mouth guards can be knocked-out, leaving the user unprotected.

Prevention of pericoronitis can be achieved by removing impacted third molars before they erupt into the mouth, or through preemptive operculectomy. A treatment controversy exists about the necessity and timing of the removal of asymptomatic, disease-free impacted wisdom teeth which prevents pericoronitis. Proponents of early extraction cite the cumulative risk for extraction over time, the high probability that wisdom teeth will eventually decay or develop gum disease and costs of monitoring to retained wisdom teeth. Advocates for retaining wisdom teeth cite the risk and costs of unnecessary operations and the ability to monitor the disease through clinical exam and radiographs.

The long-term prognosis of replanted knocked out teeth is very variable. The treatment for knocked-out teeth has progressed from a success rate of 10% to over 90%.

However, this success rate can only be achieved with the institution of optimum care within fifteen minutes to an hour of the accident. In the case of knocked-out teeth, being prepared and knowing what to do can mean the difference between a person retaining or losing replanted knocked-out teeth for life. Teeth that have been knocked out when they are fully matured, that is, when the root has completely formed, have a much better prognosis than those teeth that are immature and not fully formed. This is due to the fragility of the root. When teeth have not fully formed, the walls of the root are thinner and thus more fragile. Another complication for the prognosis is the length of time that the tooth has been out of its socket. Teeth that are replanted within fifteen minutes of the accident have an excellent prognosis. Teeth that have been extra-oral and dry stored for more than one hour have a poor prognosis. Teeth that have been placed in an optimal storage medium within one hour of the accident also have an excellent prognosis. All teeth that have been knocked out should be replanted but watched carefully for the development of root resorption. Teeth that do not have root canal treatment within two weeks of replantation also have a poor prognosis.

The presence of dental plaque or infection beneath an inflamed operculum without other obvious causes of pain will often lead to a pericoronitis diagnosis; therefore, elimination of other pain and inflammation causes is essential. For pericoronal infection to occur, the affected tooth must be exposed to the oral cavity, which can be difficult to detect if the exposure is hidden beneath thick tissue or behind an adjacent tooth. Severe swelling and restricted mouth opening may limit examination of the area. Radiographs can be used to rule out other causes of pain and to properly assess the prognosis for further eruption of the affected tooth.

Sometimes a "migratory abscess" of the buccal sulcus occurs with pericoronal infection, where pus from the lower third molar region tracks forwards in the submucosal plane, between the body of the mandible and the attachment of the buccinator muscle to the mandible. In this scenario, pus may spontaneously discharge via an intra-oral sinus located over the mandibular second or first molar, or even the second premolar.

Similar causes of pain, some which can occur in conjunction with pericoronitis may include:

- Dental caries (tooth decay) of the wisdom tooth and of the distal surface of the second molar is common. Tooth decay may cause pulpitis (toothache) to occur in the same region, and this may cause pulp necrosis and the formation of a periapical abscess associated with either tooth.

- Food can also become stuck between the wisdom tooth and the tooth in front, termed food packing, and cause acute inflammation in a periodontal pocket when the bacteria become trapped. A periodontal abscess may even form by this mechanism.

- Pain associated with temporomandibular joint disorder and myofascial pain also often occurs in the same region as pericoronitis. They are easily missed diagnoses in the presence of mild and chronic pericoronitis, and the latter may not be contributing greatly to the individual's pain (see table).

It is rare for pericoronitis to occur in association with both lower third molars at the same time, despite the fact that many young people will have both lower wisdom teeth partially erupted. Therefore, bilateral pain from the lower third molar region is unlikely to be caused by pericoronitis and more likely to be muscular in origin.

This type of failure of eruption takes place when the affected tooth is ankylosed to the bone around it. This is different than primary failure of eruption where the affected tooth/teeth were not ankylosed. In mechanical failure of eruption, affected tooth has partial or complete loss of PDL in a panoramic radiograph and teeth distal to affected tooth do not have this condition. On a percussion test, a tooth with mechanical failure of eruption will have a dull metallic sound.

RA in patients with Felty's syndrome is chronic (after 10-15 years), and presents with increased severity along with extra articular manifestations. RA can be mistaken for other conditions such as gout if not clinically diagnosed. Diagnosis can be confirmed by use of X-rays or synovial fluid analysis.

If rheumatoid arthritis is present and other symptoms occur that are not commonly found within RA itself, such as a palpable spleen, further testing should be done. A palpable spleen is not always a clinical significance, therefore CT scan, MRI, or ultrasound can be administered in order to help diagnose the condition. According to Poulin et al, dimensional guidelines for diagnosing splenomegaly are as follows:

- Moderate if the largest dimension is 11-20 cm

- Severe if the largest dimension is greater than 20 cm

In case of infection or inflammation, blood or other body fluids may be submitted for laboratory analysis.

Hearing loss is generally measured by playing generated or recorded sounds, and determining whether the person can hear them. Hearing sensitivity varies according to the frequency of sounds. To take this into account, hearing sensitivity can be measured for a range of frequencies and plotted on an audiogram.

Another method for quantifying hearing loss is a speech-in-noise test. As the name implies, a speech-in-noise test gives an indication of how well one can understand speech in a noisy environment. A person with a hearing loss will often be less able to understand speech, especially in noisy conditions. This is especially true for people who have a sensorineural loss – which is by far the most common type of hearing loss. As such, speech-in-noise tests can provide valuable information about a person's hearing ability, and can be used to detect the presence of a sensorineural hearing loss. A recently developed digit-triple speech-in-noise test may be a more efficient screening test.

Otoacoustic emissions test is an objective hearing test that may be administered to toddlers and children too young to cooperate in a conventional hearing test. The test is also useful in older children and adults.

Auditory brainstem response testing is an electrophysiological test used to test for hearing deficits caused by pathology within the ear, the cochlear nerve and also within the brainstem. This test can be used to identify delay in the conduction of neural impulses due to tumours or inflammation but can also be an objective test of hearing thresholds. Other electrophysiological tests, such as cortical evoked responses, can look at the hearing pathway up to the level of the auditory cortex.

The clinical definition of smallpox is an illness with acute onset of fever equal to or greater than followed by a rash characterized by firm, deep seated vesicles or pustules in the same stage of development without other apparent cause. If a clinical case is observed, smallpox is confirmed using laboratory tests.

Microscopically, poxviruses produce characteristic cytoplasmic inclusions, the most important of which are known as Guarnieri bodies, and are the sites of viral replication. Guarnieri bodies are readily identified in skin biopsies stained with hematoxylin and eosin, and appear as pink blobs. They are found in virtually all poxvirus infections but the absence of Guarnieri bodies cannot be used to rule out smallpox. The diagnosis of an orthopoxvirus infection can also be made rapidly by electron microscopic examination of pustular fluid or scabs. All orthopoxviruses exhibit identical brick-shaped virions by electron microscopy. If particles with the characteristic morphology of herpesviruses are seen this will eliminate smallpox and other orthopoxvirus infections.

Definitive laboratory identification of variola virus involves growing the virus on chorioallantoic membrane (part of a chicken embryo) and examining the resulting pock lesions under defined temperature conditions. Strains may be characterized by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis. Serologic tests and enzyme linked immunosorbent assays (ELISA), which measure variola virus-specific immunoglobulin and antigen have also been developed to assist in the diagnosis of infection.

Chickenpox was commonly confused with smallpox in the immediate post-eradication era. Chickenpox and smallpox can be distinguished by several methods. Unlike smallpox, chickenpox does not usually affect the palms and soles. Additionally, chickenpox pustules are of varying size due to variations in the timing of pustule eruption: smallpox pustules are all very nearly the same size since the viral effect progresses more uniformly. A variety of laboratory methods are available for detecting chickenpox in evaluation of suspected smallpox cases.

The overall case-fatality rate for ordinary-type smallpox is about 30 percent, but varies by pock distribution: ordinary type-confluent is fatal about 50–75 percent of the time, ordinary-type semi-confluent about 25–50 percent of the time, in cases where the rash is discrete the case-fatality rate is less than 10 percent. The overall fatality rate for children younger than 1 year of age is 40–50 percent. Hemorrhagic and flat types have the highest fatality rates. The fatality rate for flat-type is 90 percent or greater and nearly 100 percent is observed in cases of hemorrhagic smallpox. The case-fatality rate for variola minor is 1 percent or less. There is no evidence of chronic or recurrent infection with variola virus.

In fatal cases of ordinary smallpox, death usually occurs between the tenth and sixteenth days of the illness. The cause of death from smallpox is not clear, but the infection is now known to involve multiple organs. Circulating immune complexes, overwhelming viremia, or an uncontrolled immune response may be contributing factors. In early hemorrhagic smallpox, death occurs suddenly about six days after the fever develops. Cause of death in hemorrhagic cases involved heart failure, sometimes accompanied by pulmonary edema. In late hemorrhagic cases, high and sustained viremia, severe platelet loss and poor immune response were often cited as causes of death. In flat smallpox modes of death are similar to those in burns, with loss of fluid, protein and electrolytes beyond the capacity of the body to replace or acquire, and fulminating sepsis.