Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

34 results found
Article

Halitosis

Halitosis refers to the symptom of foul oral odour, commonly termed "bad breath", that patients can present with, usually to dental services. Pathology It is thought to be caused by the presence of volatile sulphur compounds that are produced by bacteria. Although the underlying cause can be s...
Article

Haller cells

Haller cells are also known as infraorbital ethmoidal air cells or maxilloethmoidal cells. They are extramural ethmoidal air cells that extend into the inferomedial orbital floor and are present in ~20% (range 2-45%) of patients, depending on their exact definition 1-3. In most instances they a...
Article

Hard palate

The hard palate is the horizontal bony part of the palate that forms the roof of the oral cavity and floor of the nasal cavity. It is formed by the palatine processes of the maxillae and the horizontal plates of the palatine bones. On its inferior ora) surface it is lined my oral mucosa (which c...
Article

Hashimoto thyroiditis

Hashimoto thyroiditis, also known as lymphocytic thyroiditis or chronic autoimmune thyroiditis, is a subtype of autoimmune thyroiditis. It is one of the most common thyroid disorders.  Epidemiology Typically affects middle aged females (30-50 year age group with a F:M ratio of 10-15:1).  Clin...
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Head and neck anatomy

Head and neck anatomy is important when considering pathology affecting the same area. In radiology, the 'head and neck' refers to all the anatomical structures in this region excluding the central nervous system, that is, the brain and spinal cord and their associated vascular structures and en...
Article

Head and neck squamous cell carcinomas

Head and neck squamous cell carcinomas (HNSCC) refer to SCCs of the aerodigestive tract of the head and neck rather than cutaneous SCCs. SCC is the most common tumour of the mucosa of the upper aerodigestive tract, and can occur anywhere there is squamous cell mucosa.  Epidemiology, risk factor...
Article

Heerfordt syndrome

Heerfordt(-Waldenström) syndrome or uveoparotid fever is a variant of sarcoidosis, comprising of: fever parotid enlargement facial palsy ocular involvement (anterior uveitis) Epidemiology The exact prevalence is unknown, as only isolated case reports exist. Neurologic involvement may occur...
Article

Hemifacial microsomia

Hemifacial microsomia (HFM) is the second most common congenital facial anomaly after cleft lip/palate. The condition may vary from mild to severe. Goldenhar syndrome has been described as a variant of HFM, in which vertebral anomalies and epibulbar dermoids were present. Terminology HFM is al...
Article

Hennebert sign (inner ear)

The Hennebert sign describes a positive fistula test without clinical evidence of middle ear or mastoid disease. It is associated with congenital syphilis and may also be present in Meniere disease. It has been postulated that the vestibular stimulation is mediated by fibrous bands between foot...
Article

Heterogeneous thyroid echotexture

Heterogeneous echogenicity of the thyroid gland is a non specific finding and has been associated with conditions diffusely affecting the thyroid gland. These include Hashimoto thyroiditis Graves disease
Article

High arched palate

High arched palates are a facial feature of many syndromes, although the classic association is Marfan syndrome. There are hundreds of conditions associated with high arched palates, with some of the radiologically-more important including: Down syndrome Apert syndrome Rubinstein-Taybi syndro...
Article

High riding jugular bulb

A high riding jugular bulb is distinguished from an asymmetrically large jugular bulb by its dome (roof) reaching above the internal acoustic meatus (IAM). It need not be larger than the contralateral bulb, but usually is. A run of the mill high riding jugular bulb has an intact sigmoid plate -...
Article

Hockey stick sign (thyroid hemiagenesis)

Hockey stick sign has been used to described the appearance of the thyroid gland in cases of thyroid hemiagenesis, when investigated with 99m Technetium pertechnetate thyroid scan 1. The unilateral lobe and isthmus make a shape reminiscent of a hockey stick.  See also hockey stick sign (Creutz...
Article

Holman-Miller sign (maxillary sinus)

The Holman-Miller sign (also called antral sign) is seen in juvenile nasopharyngeal angiofibroma. The anterior bowing of the posterior wall of the maxillary antrum which is seen on lateral skull film or cross-sectional imaging 1-2. This is a non-specific sign that can be produced by any slowly ...
Article

Hutchinson freckle

Hutchinson freckle, also known as lentigo maligna, is a nonfamilial precursor to lentigo maligna melanoma, which accounts for 5-15% of cases of malignant melanoma. It is most frequent in the head and neck. It should not be confused with numerous other Hutchinson named entities including: Hutch...
Article

Hutchinson sign (disambiguation)

The Hutchinson sign can refer to two signs.  Hutchinson sign (ophthalmology) Relates to involvement of the tip of the nose from facial herpes zoster. It implies involvement of the external nasal branch of the nasociliary nerve (branch of the ophthalmic division of the trigeminal nerve) and thu...
Article

Hutchinson teeth

Hutchinson’s teeth are smaller and more widely spaced than normal and are notched on their biting surfaces. It is a sign of congenital syphilis and should not be confused with: Hutchinson's triad Hutchinson pupil Hutchinson freckle Hutchinson's sign Hutchinson syndrome History and etymolo...
Article

Hutchinson triad

Hutchinson triad of congenital syphilis consists of: dental abnormalities interstitial keratosis deafness History and etymology Named after Sir Johnathan Hutchinson, English surgeon, ophthalmologist and pathologist (1828 - 1913). Hutchinson's triad should not be confused with: Hutchinson ...
Article

Hyoglossus muscle

The hyoglossus muscle is a thin, quadrilaterally shaped muscle in the upper neck and the floor of the mouth. It is one of the extrinsic muscles of the tongue. The submandibular ganglion suspended from the lingual nerve sits on it. Summary origin: hyoid bone: from the entire length of the great...
Article

Hyoid bone

The hyoid is a "horseshoe-shaped" bone that serves as a structural anchor in the mid-neck. It is a place of convergence of multiple small neck muscles that permit the pharyngeal phase of swallowing. The location of structures in the neck are often described in terms of relation to the hyoid (i.e...
Article

Hyoid elevation

Hyoid elevation is an indication on a modified barium swallow study that the pharyngeal muscles are contracting appropriately. Radiographic features Modified barium swallow With real time fluoroscopy (or videofluoroscopy) during the act of swallowing, the larynx moves upward and forward when ...
Article

Hyperattenuating paranasal sinus opacification

Hyperattenuating paranasal sinus opacification can arise in a number of situations. These include fungal sinus disease inspissated secrections acute haemorrhage into sinus Differential diagnosis In some situations can consider early calcification within the sinus
Article

Hyperostosis of the skull (differential)

Hyperostosis of the skull has many causes, broadly divided into focal or diffuse. Diffuse Paget's disease of bone metastatic disease, especially prostate carcinoma chronic, severe anaemia hyperparathyroidism acromegaly osteopetrosis hyperostosis frontalis interna long-term phenytoin use...
Article

Hyperparathyroidism

Hyperparathyroidism is the effect of excess parathyroid hormone (PTH) in the body. It can be primary, secondary or tertiary. There are many characteristic imaging features predominantly involving the skeletal system. Pathology Increased levels of the PTH lead to increased osteoclastic activity...
Article

Hypertelorism

Hypertelorism refers to an abnormal increase in distance between any two organs although some authors use the term synonymously with orbital hypertelorism meaning an abnormal increase in distance between the two eyes. The article mainly focuses on the latter. The abnormality is similar to teleca...
Article

Hypodontia

Hypodontia refers to the congenital absence of one or more teeth. Epidemiology Hypodontia is common, affecting ~15% of the population with a recognised variations in ethnicities, e.g. prevalence of 1% in indigenous Australians through to 30% in Japanese populations. There is a female preponder...
Article

Hypoglossal canal

The hypoglossal canal is located between the occipital condyle and jugular tubercle and runs obliquely forwards (posteromedial to anterolateral) allowing the hypoglossal nerve (12th cranial nerve) to exit the posterior cranial fossa.  Its proximal portion is often divided by a fibrous (sometime...
Article

Hypoparathyroidism

Hypoparathyroidism results from reduced secretion of parathyroid hormone by the parathyroid glands. It results in hypocalcaemia.  Clinical presentation tetany: peripheral paresthesia, carpopedal spasm, seizures emotional lability, depression and anxiety, psychosis short stature Pathology T...
Article

Hypopharyngeal squamous cell carcinoma

Squamous cell carcinoma of the hypopharynx is relatively uncommon, carries the worst prognosis of any head and neck squamous cell carcinoma (HNSCC), and is a challenge to diagnose and treat.  Hypopharyngeal carcinoma is relatively uncommon representing only 10% of all proximal aerodigestive tra...
Article

Hypopharyngeal squamous cell carcinoma (staging)

Staging of hypopharyngeal squamous cell carcinoma is performed using the TNM staging system. TNM staging Primary tumour staging (T) T1: limited to 1 subsite AND tumour size ≤ 2 cm in greatest dimension T2: extends into adjacent subsite or area (larynx, oropharynx) and/or tumour size betw...
Article

Hypopharyngeal tumours (T staging)

T staging of hypopharyngeal tumours is as follows: Definition The hypopharynx includes the pyriform sinuses, the lateraland posterior hypopharyngeal walls, and the postcricoid region. T1: tumour is limited to one subsite of the hypopharynx and 2 cm or less in greatest dimension T2: tumour in...
Article

Hypopharynx

The hypopharynx or laryngopharynx forms part the pharynx, being the continuation of the oropharynx superiorly and oesophagus inferiorly.  Gross anatomy The hypopharynx begins as the continuation of the oropharynx at the pharyngoepiglottic fold (which is at the level of the hyoid bone) superior...
Article

Hypotelorism

Hypotelorism refers to an abnormal decrease in distance between any two organs although some authors use the term synonymously with orbital hypotelorism meaning an abnormal decrease in the distance between the two eyes (the eyes appear too close together). The article mainly focuses on the latte...
Article

Hyrtl’s fissure

Hyrtl's fissure (also known as tympanomeningeal fissure) is a congenital infra-labyrinthic fissure. It is a very rare cause of spontaneous CSF ottorhoea. Radiographic features CT this can be diagnosed on axial slices and coronal reformations CT cisternography and radionuclide cisternography ...

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