Articles
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1,949 results found
Article
Schneiderian papilloma
Schneiderian papillomas, also known as sinonasal papillomas, are benign sinonasal tumors that arise from the Schneiderian epithelium of the nasal cavity and paranasal sinuses.
Epidemiology
Schneiderian papillomas account for ~2.5% (range 0.4-4.7%) of sinonasal tumors 2.
Pathology
The WHO cl...
Article
Pituitary macroadenoma
Pituitary macroadenomas are the most common suprasellar mass in adults, and responsible for the majority of transsphenoidal hypophysectomies. They are defined as pituitary adenomas greater than 10 mm in size and are approximately twice as common as pituitary microadenomas.
On imaging, they usu...
Article
Posterior ciliary arteries
The posterior ciliary arteries are usually paired branches arising from the ophthalmic artery, one medial and one lateral, each giving off a number of branches that supply the uvea 1.
Close to the optic nerve, are the short posterior ciliary arteries, usually numbering 16-20; these supply the p...
Article
Thyroid-associated orbitopathy
Thyroid-associated orbitopathy, also known as thyroid-associated ophthalmopathy or thyroid eye disease, is the most common cause of proptosis in adults and is most frequently associated with Graves disease. On imaging, it is characterized by bilateral and symmetrical enlargement of the extraocul...
Article
Infratemporal fossa
The infratemporal fossa is a complex space of the face that lies posterolateral to the maxillary sinus, below the skull base, and between the pharyngeal sidewall and mandibular ramus. It overlaps with the masticator space and prestyloid parapharyngeal space.
Gross anatomy
The infratemporal fos...
Article
Lipoma
Lipomas are benign tumors composed of mature adipocytes. They are the most common soft tissue tumor, seen in ~2% of the population.
Epidemiology
Patients typically present in adulthood (5th-7th decades).
Associations
In some cases, multiple lipomas are associated with syndromes and other di...
Article
Vagal schwannoma
Vagal schwannomas are uncommon benign masses that can occur anywhere along the course of the vagus nerve but most commonly occur in the cervical region.
Epidemiology
Most commonly occurs in the 3rd to 5th decades. No sex predilection 3.
Clinical presentation
Patients may be asymptomatic. Whe...
Article
Skull vault osteoma
Skull vault osteomas are benign primary bone tumors that are commonly incidentally discovered. They are less common than paranasal sinus or mandibular osteomas.
Clinical presentation
Skull vault osteomas are typically asymptomatic but may present as painless, slow-growing masses or with compr...
Article
Pituitary gland
The pituitary gland (a.k.a. hypophysis cerebri), together with its connections to the hypothalamus, acts as the main endocrine interface between the central nervous system and the rest of the body.
Gross anatomy
The pituitary gland sits atop the base of the skull in a concavity within the sph...
Article
Pleomorphic adenoma of the salivary glands
Pleomorphic adenomas of the salivary glands, also known as benign mixed tumors (see below), are the most common salivary gland tumors. The salivary glands are the most common site of pleomorphic adenomas.
On imaging, they commonly present as well-circumscribed rounded masses, most commonly loca...
Article
High riding jugular bulb
A high riding jugular bulb indicates the dome (roof) of the jugular bulb extends more superiorly in the petrous temporal bone than is conventional. The transverse level above which a jugular bulb is considered high riding has been variably defined as the following 1,6,8:
floor of the internal a...
Article
Non-pulsatile tinnitus
Non-pulsatile tinnitus is a form of tinnitus where there is a continuous ringing sensation of the ears. It is thought to have a considerable subjective component in many individuals.
Pathology
Many factors have been postulated, inclusive of 1-5:
cerumen impaction
middle ear infection
medica...
Article
Alport syndrome
Alport syndrome is a hereditary disease characterized by progressive sensorineural hearing loss, renal disease and, at times, ocular lesions.
Clinical presentation
hematuria
sensorineural hearing loss: typically high frequency 2
ocular abnormalities
anterior lenticonus which may result in c...
Article
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...
Article
Supraclavicular triangle
The supraclavicular triangle is one of the paired triangles in the posterior triangle of the neck. The triangles of the neck are surgically focussed, first described from early dissection-based anatomical studies which predated cross-sectional anatomical description based on imaging (see deep sp...
Article
Iodine-123
Iodine-123 (I123 or I-123) is a radioisotope of the element iodine (atomic number 53) used in nuclear medicine imaging including to scan the thyroid gland.
Production
Iodine-123 is produced in a cyclotron by bombarding Xenon-124 with a proton. Xenon-124 either will absorb the proton and loses...
Article
Branchial apparatus
The branchial (or pharyngeal) apparatus is the complex region in the developing embryo between the head and chest that develops in the fourth week and provides bilateral ridges and valleys that subsequently develop into numerous anatomic structures of the head, face, palate and anterior neck. Th...
Article
Axenfeld-Rieger syndrome
Axenfeld-Rieger syndrome is a rare spectrum of disorders with an autosomal dominant pattern of inheritance 6. The syndrome incorporates all of 5:
Axenfeld anomaly: posterior embryotoxon and peripheral irido-corneal adhesions
Rieger anomaly: findings of Axenfeld anomaly along with corectopia (m...
Article
Von Hippel-Lindau disease
Von Hippel-Lindau (vHL) disease is characterized by the development of numerous benign and malignant tumors in different organs (at least 40 types 1) due to mutations in the VHL tumor suppressor gene on chromosome 3.
Epidemiology
The disease is rare with an estimated prevalence of 1:35,000-50,...
Article
Skull
The skull (TA: cranium) is the superior-most part of the human skeleton and houses the brain and includes the skeletal elements of the face. It consists of numerous bones connected to each other by sutures which renders them immobile.
Terminology
Variability in which bones to include and how t...
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