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 continuously improved upon by countless contributing members. Our dedicated editors oversee each edit for accuracy and style. Find out more about articles.
More than 200 results
Article
Fossula post fenestram
The fossula post fenestram is a sac-like evagination of connective tissue within the otic capsule just posterior to the oval window. The region around the fossula is one of the less common areas of predilection for otosclerosis.
It arises from the vestibule and is thus one of three extensions o...
Article
HPV-mediated (p16-positive) oropharyngeal cancer (staging)
Human papillomavirus (HPV)-mediated oropharyngeal (p16+) cancer staging refers to TNM staging of squamous cell carcinomas of the oropharynx that test positive for p16, an immunohistochemical proxy for HPV infection. Nodal metastases of p16+ squamous cell carcinoma without an identified primary t...
Article
Asterion
The asterion is the junction on the side of the posteroinferior calvarium where three sutures meet:
parietomastoid suture
occipitomastoid suture
lambdoid suture
It represents the site of the closed mastoid fontanelle. It is located at the posterior end of the parietotemporal suture, whereas ...
Article
Ocular external rotators
The ocular external (lateral) rotators are the extra-ocular muscles responsible for external rotation (extorsion) of the globe:
inferior oblique (primary function)
inferior rectus (secondary function)
Article
Oropharyngeal (p16-negative) cancer (staging)
Oropharyngeal (p16-) cancer staging refers to TNM staging of carcinomas originating in the oropharynx that are not human papillomavirus (HPV)-associated. This system most commonly pertains to squamous cell carcinomas that tested negative for p16, an immunohistochemical proxy for HPV infection, o...
Article
Cogan syndrome
Cogan syndrome is a rare vasculitis of young adults that is primarily characterized by 1,4,6:
inflammatory eye disease (classically interstitial keratitis) 6
audiovestibular dysfunction (similar to Meniere disease) 6
Epidemiology
Cogan syndrome is rare and can occur in people of any age and ...
Article
Congenital granular cell myoblastoma
A congenital granular cell myoblastoma (also known as congenital epulis) is a very rare benign tumor which classically presents in the fetal-neonatal population.
Epidemiology
It occurs almost exclusively in females when it presents in the fetal-neonatal population although no such predilection...
Article
Carotid space
The carotid space, the suprahyoid portion of which is also known as the poststyloid parapharyngeal space, is a deep compartment of the head and neck bound by the carotid sheath.
Terminology
The "carotid space" terminology was introduced by some radiologists to facilitate differential diagnosis...
Article
Parotid space
The parotid space is one of the deep compartments of the head and neck and, as the name suggests, is mostly filled with the parotid gland. It is the most lateral major suprahyoid neck space.
Gross anatomy
The parotid space is a roughly pyramidal space, the broad elongated base facing laterally...
Article
Enophthalmos
Enophthalmos refers to the posterior displacement of the globe in the orbit. It implies that the globe itself is normal and is caused by either one or a combination of 1:
structural alterations in the bony orbit
orbital fat atrophy
retraction
Specific causes include 2:
orbital blowout fract...
Article
Ice cream cone sign (vestibular schwannoma)
The ice cream cone sign refers to the appearance of a medium-sized (1.5 to 3.0 cm) vestibular schwannoma. The intracanalicular component represents the cone and the cerebellopontine angle (CPA) (cisternal) component representing the ice cream ball.
See also
ice cream cone sign (middle ear ossi...
Article
Carotid bifurcation
The carotid bifurcation is the point at which the common carotid artery terminates. As it does so, it forms the internal and external carotid arteries which go on to supply the head and neck.
The height of the carotid bifurcation is noted to be highly variable in the literature. Most frequently...
Article
Crista galli
The crista galli is a thick, midline, smooth triangular process arising from the superior surface of the ethmoid bone, projecting into the anterior cranial fossa. It separates the olfactory bulbs, which lie on either side of it in the olfactory fossae of the cribriform plate. It serves as an ant...
Article
Hypothyroidism
The clinical syndrome of hypothyroidism is marked by inadequate thyroid hormone production, resulting in a decreased rate of cellular metabolism. It may be primary, in which the dysfunction pertains to the thyroid gland itself, or secondary, due to hypothalamic or pituitary dysfunction 1.
Epide...
Article
Heterogeneous thyroid echotexture
Heterogeneous echogenicity of the thyroid gland is a non-specific finding and is associated with conditions diffusely affecting the thyroid gland. These include:
Hashimoto thyroiditis
Graves disease
The presence of heterogenous thyroid echogenicity may reduce sensitivity of detection of thyro...
Article
Ameloblastic fibro-odontoma
Ameloblastic fibro-odontoma (AFO) is a rare benign mixed odontogenic lesion that usually arises in the maxilla and mandible. Once classified as a distinct entity, the lesion resembles an ameloblastic fibroma but contains hard odontoid tissue. It is now thought to represent part of the spectrum o...
Article
Lymph node enlargement
Lymph node enlargement (rarely lymphadenomegaly) is often used synonymously with lymphadenopathy, which is not strictly correct.
Terminology
Lymphadenopathy (or adenopathy) is, if anything, a broader term than lymph node enlargement, referring to any pathology of lymph nodes, not necessarily r...
Article
Foramen tympanicum
The foramen tympanicum (plural: foramina tympanica), also known as foramen of Huschke, is an anatomical variation in the external acoustic canal (EAC), where a bony defect connects the EAC to the temporomandibular joint (TMJ).
Epidemiology
Various studies have reported on the occurrence of a f...
Article
Behçet disease
Behçet disease is a multisystemic and chronic inflammatory vasculitis of unknown etiology.
Epidemiology
The mean age at which Behçet disease occurs is 20-30 years. The disease is most prevalent in the Mediterranean, Middle East and East Asia. It is rarely reported in Europe. The highest incide...
Article
Cutaneous carcinoma of the head and neck (staging)
Cutaneous carcinoma of the head and neck staging refers to TNM staging of nonmelanoma skin cancer involving the scalp, external ear, neck, or face including external lips. The system applies to cutaneous squamous cell carcinoma and numerous other skin carcinomas, notably excluding eyelid carcino...
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