Halitosis refers to the symptom of foul oral odour, commonly termed "bad breath", that patients can present with, usually to dental services.
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...
The hard palate is the anterior 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 oral surface it is lined by oral mucosa...
The harlequin eye deformity may be seen in unilateral (plagiocephaly) or bilateral (brachycephaly) coronal suture synostosis, and refers to the elevation of the superolateral corner of the orbit.
The term harlequin eye derives from the appearance of the eyes on a harlequin mask with their exagg...
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.
Typically affects middle aged females (30-50 year age group with a F:M ratio of 10-15:1).
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...
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...
Heerfordt(-Waldenström) syndrome or uveoparotid fever is a variant of sarcoidosis, comprising of:
ocular involvement (anterior uveitis)
The exact prevalence is unknown, as only isolated case reports exist. Neurologic involvement may occur...
Hemifacial hyperplasia or hemifacial hypertrophy is a rare developmental anomaly characterised by asymmetric growth of hard and soft tissues of the face 1.
These asymmetries are often noted at birth and are usually accentuated with increasing age, especially around puberty 2.
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.
HFM is al...
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 Ménière disease.
It has been postulated that the vestibular stimulation is mediated by fibrous bands between foot...
Heterogeneous echogenicity of the thyroid gland is a non-specific finding and is associated with conditions diffusely affecting the thyroid gland. These include:
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:
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 -...
High-velocity penetrating brain injuries, in practical terms most often due to cranial gunshot injuries, are a form of penetrating traumatic brain injuries, which are much less common than blunt traumatic brain injuries and distinguished from low-velocity penetrating brain injuries (such as stab...
Hockey stick sign has been used to describe 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.
hockey stick sign (Creutzf...
The Holman-Miller sign (also called the antral sign) is seen in juvenile nasopharyngeal angiofibroma; it refers to the anterior bowing of the posterior wall of the maxillary antrum as seen on a lateral skull radiograph or cross-sectional imaging 1,2.
This is a non-specific sign that can be prod...
Hutchinson freckle, also known as lentigo maligna, is a non-familial 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:
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...
Hutchinson 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:
History and etymology
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.
origin: hyoid bone: from the entire length of the great...
The hyoid is a "horseshoe-shaped" bone that serves as a structural anchor in the mid-neck. It is the only bone in the human body that does not directly articulate with another bone, sesamoids aside. It is a place of convergence of multiple small neck muscles that permit the pharyngeal phase of s...
Hyoid elevation on a modified barium swallow study indicates that the pharyngeal muscles are contracting appropriately.
Modified barium swallow
With real time fluoroscopy (or videofluoroscopy) during the act of swallowing, the larynx moves upward and forward when there i...
Hyperattenuating paranasal sinus opacification can arise in a number of situations:
fungal sinus disease
acute haemorrhage into sinus (haemosinus)
In some situations can consider early calcification within the sinus.
Hyperostosis of the skull has many causes, broadly divided into focal or diffuse.
Paget's disease of bone
metastatic disease, especially prostate carcinoma
chronic, severe anaemia
hyperostosis frontalis interna
long-term phenytoin use...
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.
Increased levels of the PTH lead to increased osteoclastic activity...
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...
Hypodontia refers to the congenital absence of one or more teeth.
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...
Hypoglobus refers to the inferior displacement of the globe into the orbit. It may or may not be associated with enophthalmos.
Hypoglobus is most commonly caused by fracture of the orbital floor but may be due to other causes:
silent sinus syndrome
orbital foreign bodies
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...
Hypoparathyroidism results from reduced secretion of parathyroid hormone by the parathyroid glands. It results in hypocalcaemia.
tetany: peripheral paresthesia, carpopedal spasm, seizures
emotional lability, depression and anxiety, psychosis
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...
Staging of hypopharyngeal squamous cell carcinoma is performed using the TNM staging system.
Primary tumour staging (T)
limited to 1 subsite AND
tumour size ≤ 2 cm in greatest dimension
extends into adjacent subsite or area (larynx, oropharynx) and/or
tumour size betw...
T staging of hypopharyngeal tumours is as follows:
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...
The hypopharynx or laryngopharynx forms the most inferior portion of the pharynx, being the continuation of the oropharynx superiorly and both the larynx and oesophagus inferiorly.
The hypopharynx begins as the continuation of the oropharynx at the pharyngoepiglottic fold (which...
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...
Hyrtl's fissure (also known as tympanomeningeal fissure) is a congenital infra-labyrinthic fissure. It is a very rare cause of spontaneous CSF ottorhoea.
this can be diagnosed on axial slices and coronal reformations
CT cisternography and radionuclide cisternography ...