The flat floor of fourth ventricle sign is useful in detecting a pontine mass and is a sign of mass effect. The normal floor of the fourth ventricle (remember that the floor is anterior) normally slopes upwards towards the midline, with the facial colliculi visible on either side.
It is a non-...
Anoxic brain injury, also known as global hypoxic-ischaemic injury, is seen in all age groups (from antenatal to the elderly) as a result of numerous aetiologies. The pattern of injury depends on a number of factors including:
age of the patient (brain maturity)
neonatal hypoxic-ischaemic ence...
Denervation changes in muscles can be observed in a number of settings.
in the very early stage, muscle signal may be normal
earliest change is increased T2 signal (best seen on a fat saturated T2WI such as STIR)
chronic changes are marked by muscle atrophy and fat...
Epidermolysis bullosa refers to a rare group of genetically determined conditions characterised by blistering of the skin. This can be limitted to the soles and palms or extensive whole body involvement.
Radiological manifestations are limited to the mucosa of the gastro...
Ethmocephaly refers to a rare type of midline cranio-facial anomaly that is characterised by the presence of extreme hypotelorism, arrhinia and a midline proboscis.
holoprosencephaly 1-2: particularly alobar holoprosencephaly
Cebocephaly refers to a type of rare midline craniofacial anomaly where there is a single nostril (which usually ends blindly 6-7) with proboscis-like nose 8 and hypotelorism.
holoprosencephaly: particularly alobar holoprosencephaly
A contrecoup injury of the knee is a bone contusion of the posterior lip of the medial tibial plateau. It occurs during knee reduction after a pivot shift injury and is highly associated to ACL tear 1, and peripheral tear or meniscocapsular separation of the medial meniscus posterior horn 2.
Aspergillus clavatus is one of the species of Aspergillus that can cause pathology in humans. It is allergenic and causes a hypersensitivity pneumonitis called malt-workers lung.
The melting ice cube sign describes the resolution of pulmonary haemorrhage following pulmonary embolism (PE).
When there is pulmonary haemorrhage without infarction following PE, the typical wedge-shaped, pleural-based opacification (Hampton's hump) resolves within a week while preserving its...
The eye of the tiger sign refers to abnormal low T2 signal on MRI (due to abnormal accumulation of iron) in the globus pallidus with a longitudinal stripe of high signal (due to gliosis and spongiosis) that can be seen in:
Hallervorden-Spatz syndrome: classical but not 100% pathognomonic
Meconium pseudocyst formation is a complication that can occur with meconium peritonitis.
It occurs when the extruded meconium becomes walled off within the peritoneal space.
May be seen as a rim calcified mass within the abdomen.
Delayed myocardial enhancement, as seen on cardiac MRI, occurs when gadolinium contrast material seeps into fibrotic or necrotic myocardial tissue. It is due to a number of aetiologies, and has variable appearances.
subendocardial enhancement indicates an ischaemic aetiology
Rett syndrome (RS) is a rare neurodegenerative disease seen in young girls in the 2nd to 4th months of life.
Following a period of normal development, with a normal prenatal and perinatal period with normal developmental progress for the first 5–6 months of life, a decele...
A fourth ventriculocoele is large posterior fossa cyst which remodels, thins and eventually erodes through the occipital bone to form an occipital encephalocoele.
It may be be classified as part of the Dandy-Walker continuum, but this is controversial.
The pars tensa is the tense portion of the tympanic membrane and refers to the main portion of the membrane.
It extends from the anterior and posterior malleolar folds at the level of the lateral process of malleus to the inferior extent of the tympanic membrane at its attachment.
The pars flaccida is the flaccid portion of the tympanic membrane and represents a small portion of the membrane.
It extends upwards from the anterior and posterior malleolar folds at the level of the lateral process of malleus. Hence, it sits between the scutum and malleus.
Apple-peel intestinal atresia, also known as type IIIb or Christmas tree intestinal atresia, is a rare form of small bowel atresia in which the duodenum or proximal jejunum ends in a blind pouch and the distal small bowel wraps around its vascular supply in a spiral resembling an apple peel. Oft...
Scaphoid non-union is one of the complications of scaphoid fracture because of the unique anatomy of the scaphoid and its vascular supply.
There are four types of non-union:
fibrous (delayed union): stable with no deformity or collapse
cystic: unstable and early collapse patterns
Kager's triangle is a sharply marginated radiolucent triangle seen posteriorly on lateral radiographs of the ankle. It represents the Kager fat pad.
It is bordered anteriorly by the flexor hallucis longus (FHL) muscle and tendon, posteriorly by the Achilles tendon, and inferiorly by the calcane...
The submandibular glands are paired salivary glands located behind and below the ramus of the mandible. They secrete saliva that is excreted into the oral cavity via the submandibular duct that connects the gland to the floor of the mouth.
Its lower superficial lobe continues as ...