Articles

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16,910 results found
Article

Carcinoma ex pleomorphic adenoma

Carcinoma ex pleomorphic adenoma is the most common of three malignant mixed tumors of salivary glands, and are thought to arise from pre-existing pleomorphic adenomas (historically also called benign mixed tumors, but see below) 1,3. Epidemiology These tumors usually occur in older patients (...
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Pleomorphic adenoma

Pleomorphic adenomas, also known by the misnomer benign mixed tumors (BMTs), are benign epithelial neoplasms related to glandular tissue. They have a small but real risk of malignant transformation. For a discussion of specific sites of pleomorphic adenoma, please refer to pleomorphic adenoma ...
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Minor salivary gland tumors

Minor salivary gland tumors are a subtype of salivary gland tumors originating from the minor salivary glands, which are found in the lips, tongue, hard palate, and the mucosa of the oropharynx and larynx, among other locations. Epidemiology MSGTs account for ~15% of all salivary gland tumors....
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Salivary gland tumors

Salivary gland tumors are variable in location, origin, and malignant potential.  Pathology In general, the ratio of benign to malignant tumors is proportional to the gland size; i.e. the parotid gland tends to have benign neoplasms, the submandibular gland 50:50, and the sublingual glands and...
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Anterior ethmoidal artery

The anterior ethmoid artery is a branch of the ophthalmic artery. It supplies the anterior and middle ethmoidal sinuses, frontal sinus, the lateral nasal wall and the nasal septum (see nasal cavity). Gross anatomy It traverses the anterior ethmoidal foramen with the anterior ethmoidal nerve (w...
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Accessory maxillary ostium

Accessory maxillary ostia are a common anatomic variant usually found incidentally on CT scans of the paranasal sinuses. Accessory ostia of the maxillary sinus are common, occurring in up to 40% of patients 1. No significant association has been found between the presence of accessory ostia and ...
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Uncinate process

The uncinate process of the ethmoid bone is a thin hook-like osseous structure of the wall of the lateral nasal cavity. It is a component of the ostiomeatal complex. Gross anatomy Together with the ethmoid bulla, it forms the boundaries of the hiatus semilunaris and ethmoid infundibulum. The ...
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Paradoxical middle turbinate

Paradoxical middle turbinate is a rare developmental cause of nasal obstruction. It refers to an inferomedially curved middle turbinate edge with the concave surface facing the nasal septum and usually occurs bilaterally. Epidemiology Paradoxical middle turbinate is a rarely encountered anomal...
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Ostiomeatal complex

The ostiomeatal complex (OMC) or ostiomeatal unit (OMU), sometimes less correctly spelled as osteomeatal complex, is a common channel that links the frontal sinus, anterior ethmoid air cells and the maxillary sinus to the middle meatus, allowing airflow and mucociliary drainage.  Gross anatomy ...
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Concha bullosa

Concha bullosa (plural: conchae bullosae) (also known as middle turbinate pneumatization) is a common finding and although associated with deviation of the nasal septum, it is usually of little clinical importance. Epidemiology Concha bullosa is a normal variant and is one of the most common v...
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Deviated nasal septum

Deviated nasal septums are a common, usually incidental, finding seen on brain and paranasal sinus CT studies. They are commonly seen with external nose deformities.  Clinical presentation Symptomatic patients can present with unilateral nasal obstruction or less commonly epistaxis, obstructiv...
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Keros classification of olfactory fossa

The Keros classification is a method of classifying the depth of the olfactory fossa. Usage The Keros classification remains widely used, although its simplicity has been criticized, and alternative classifications have been proposed (e.g. Gera classification and Thailand-Malaysia-Singapore (T...
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Papilledema

Papilledema refers to swelling of the optic disc related to increased intracranial pressure. Terminology Care must be taken to not use the term papilledema for all causes of optic nerve head elevation. Although papilledema literally means swelling of the optic disc (nerve head/papilla), in oph...
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Symphalangism

Symphalangism refers to ankylosis or synostosis of the interphalangeal joints (i.e. fusion of the phalanges) in either the toes or the fingers. Less commonly, the metacarpophalangeal joints may be affected. Epidemiology One study reports symphalangism of the fifth toe in ~55% (range 40-75%) of...
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Pericarditis

Pericarditis is defined as inflammation of the pericardium. It is normally found in association with cardiac, thoracic or wider systemic pathology and it is unusual to manifest on its own. Epidemiology Pericarditis is the most common pericardial disease worldwide and accounts for about 0.1-0.2...
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Petromastoid canal

The petromastoid canal (also known as the subarcuate canaliculus or antrocerebellar canal of Chatellier) is a channel in the petrous temporal bone that joins the mastoid antrum to the posterior cranial fossa. It contains the subarcuate artery and vein 1. The majority of petromastoid canals are ...
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CSF otorrhea

CSF otorrhea is defined as leakage of cerebrospinal fluid (CSF) from the subarachnoid space into the middle ear cavity or mastoid air cells and then out the ear via a perforation in the tympanic membrane or defect in the external ear. Epidemiology There are a number of underlying causes (see b...
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Fogging phenomenon (cerebral infarct)

The fogging phenomenon is seen on non-contrast CT or MRI of the brain and represents a transient phase of the evolution of cerebral infarct where the region of cortical infarction regains a near-normal appearance. Radiographic features CT During the first week following a cortical infarct, hy...
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Ventricular system

The ventricular system in the brain is a series of interconnecting spaces and channels within the brain composed of cerebrospinal fluid (CSF). CSF is produced by ependymal cells which line the ventricles. They are continuous with the central canal. Ventricles contain around 20% of the total aver...
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Circle of Willis

The circle of Willis (COW) or circulus arteriosus is an arterial polygon (heptagon) formed as the internal carotid and vertebral systems anastomose around the optic chiasm and infundibulum of the pituitary stalk in the suprasellar cistern. This communicating pathway allows equalization of blood-...

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