Items tagged “refs”
2,976 results
Article
Odontogenic myxoma
Odontogenic myxomas are rare tumors that involve the mandible or maxilla and account for 3-6% of odontogenic tumors 2.
Epidemiology
Typically seen in the 2nd to 3rd decades of life (slightly earlier than ameloblastomas). They are usually not painful.
Pathology
Arises from mesenchymal odontog...
Article
Odontoma
Odontomas are one of the most common mandibular lesions encountered and the most common odontogenic tumors of the mandible. They account for up to two-thirds of all such tumors; the next most common are ameloblastomas, making up the majority of the remaining one-third.
Epidemiology
They can oc...
Article
Olfactory nerve
The olfactory nerve is the first (CN I) cranial nerve (TA: nervus olfactorius or nervus cranialis I) and is responsible for conveying the sense of smell from the nasal cavity to the brain. Strictly speaking, the term olfactory 'nerve' refers only to the short first order neurons (olfactory filam...
Article
Middle ear ossicles
There are three tiny articulating bones in the middle ear known as ossicles (from lateral to medial):
malleus
incus
stapes
Their role is to mechanically amplify the vibrations of the tympanic membrane and transmit them to the cochlea where they can be interpreted as sound. They are located i...
Article
Otomastoiditis
Otomastoiditis refers to inflammation of both the middle ear (otitis media) and mastoid (mastoiditis), can be divided into two distinct entities:
acute otomastoiditis: usually due to bacterial infection
chronic otomastoiditis: usually due to Eustachian tube dysfunction
Article
Posterior cerebral artery (PCA) infarct
Posterior cerebral artery (PCA) infarcts arise, as the name says, from occlusion of the posterior cerebral artery. It is a type of posterior circulation infarction.
Epidemiology
Posterior cerebral artery strokes are believed to comprise approximately 5-10% of ischemic strokes 6.
Clinical pres...
Article
Osteonecrosis causes (mnemonic)
Mnemonics for the causes of osteonecrosis (previously known as avascular necrosis):
STARS
PLASTIC RAGS
ASEPTIC
Mnemonics
STARS
Most common causes:
S: steroids, SLE
T: trauma (e.g. femoral neck fracture, hip dislocation, scaphoid fracture, slipped capital femoral epiphysis 2)
A: alcohol ...
Article
Panner disease
Panner disease is osteonecrosis of the capitellum. It should be distinguished from osteochondritis dissecans of the elbow which also affects the capitellum.
Epidemiology
Panner disease is typically seen in children (5-10 years of age), although it is also seen in throwers due to repeated trau...
Article
Patellar tendon rupture
Patellar tendon rupture is one of the extensor mechanism of the knee injuries and occurs almost invariably at either the patellar or tibial insertion of the patellar tendon, when in the setting of trauma, and is often associated with a small avulsion fracture. Most commonly, it is at the superi...
Article
Persistent primitive trigeminal artery
Persistent primitive trigeminal artery (PPTA) is the most common type of the four persistent carotid-vertebrobasilar anastomoses. It is present in 0.1-0.6% of cerebral angiograms and is usually unilateral.
In utero, the trigeminal artery supplies the basilar artery before the development of the...
Article
Pine cone bladder
A pine cone bladder or Christmas tree bladder is a cystographic appearance in which the bladder is elongated and pointed with a thickened, trabeculated wall. It is typically seen in severe neurogenic bladder with increased sphincter tone (detrusor sphincter dyssynergia) due to suprasacral lesion...
Article
Pituitary stalk
The pituitary stalk, also known as the infundibulum or infundibular stalk, is largely outside the blood brain barrier like the rest of the pituitary and therefore normally enhances following the administration of gadolinium. It gradually tapers inferiorly, and superiorly is spread by the infundi...
Article
Pituitary stalk abnormal enhancement (differential)
Abnormal nodular enhancement of the pituitary stalk can be seen in a number of entities.
Differential diagnosis
tumors
germinoma
craniopharyngioma
hypothalamic glioma
pituitary lymphoma
pituicytoma
granular cell tumor of the pituitary (pituitary choristoma)
pilocytic astrocytoma of the...
Article
Pneumatized dorsum sella
Pneumatization of the dorsum sella is not uncommon, but needs to be remembered as an unusual site of sinus disease, which otherwise may be mistaken for intracranial of pituitary disease.
Article
Portal hypertensive gastroenterocolopathy
Portal hypertensive gastroenterocolopathy is a finding in portal hypertension, whereby chronic portal venous congestion leads to dilatation and ectasia of the submucosal vessels of the stomach (portal hypertensive gastropathy), small bowel (portal hypertensive enteropathy) and/or large bowel (po...
Article
Pregnancy-related osteonecrosis
Pregnancy-related osteonecrosis, also known as pregnancy-related avascular necrosis, is a common cause of femoral head osteonecrosis. Since the femoral head is relatively deficient in blood supply, it is particularly vulnerable to osteonecrosis.
Pathology
The pathophysiology is thought to be d...
Article
Pulmonary edema grading
One pulmonary edema grading based on chest radiograph appearances and pulmonary capillary wedge pressure (PCWP) is as follows:
grade 0: normal chest radiograph, PCWP 8-12 mmHg
grade 1: shows evidence of upper lobe diversion on a chest radiograph, PCWP 13-18 mmHg
grade 2: shows interstitial ed...
Article
Quadriceps tendon
The quadriceps tendon is a thick tendon extending to the patella made up of contributions from all four quadriceps muscles. It classically has a trilaminar structure:
superficial layer: rectus femoris
middle layer: vastus medialis, vastus lateralis
deep layer: vastus intermedius
It continues...
Article
Racing car sign (callosal dysgenesis)
The racing car sign refers to widely spaced lateral ventricles due to agenesis of the corpus callosum with intervening Probst bundles. Appearances on axial MRI or CT are reminiscent of a Formula One car seen from above, with the tyres represented by the widely-spaced frontal horns, and the dilat...
Article
Ramsay Hunt syndrome
Ramsay Hunt syndrome, also known as herpes zoster oticus or Ramsay Hunt syndrome type 2, is shingles of the facial nerve. It is due to reactivation of the varicella zoster virus (VZV) in the geniculate ganglion.
Clinical presentation
Ramsay Hunt syndrome classically presents with a triad of 3,...
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