Articles
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16,918 results
Article
Medulloblastoma
Medulloblastomas are the most common malignant brain tumors of childhood, most often presenting as midline masses in the roof of the 4th ventricle (at the superior medullary velum) with associated mass-effect and hydrocephalus. Treatment typically consists of surgical resection, radiation therap...
Article
Portal venous flow
Portal venous flow is normally towards the liver (hepatopetal), with the normal main portal vein peak systolic velocities usually measuring 20-40 cm/s 1,3.
In pathological situations, the flow velocity may decrease or even invert resulting in hepatofugal flow.
The flow waveform is usually smoo...
Article
Hydatid disease
Hydatid cysts result from infection by the Echinococcus tapeworm species and can result in cyst formation anywhere in the body.
Epidemiology
Cystic echinococcosis has a worldwide geographical distribution. The Mediterranean basin is an important endemic area 6,7.
Pathology
Two main species o...
Article
Serpent sign
The serpent sign, (also knowns as the snake sign), is a sign described in hydatid disease. The WHO classification (2001) or Gharbi classification (1985) of hydatid disease describe several stages on ultrasound 1.
During the active stage, the cyst is composed of three layers: the outer (pericyst...
Article
Borchardt's triad (gastric volvulus)
Borchardt's triad comprises the classic three symptoms diagnostic of gastric volvulus 1:
severe sudden epigastric pain
intractable retching without vomiting
inability to pass a nasogastric tube
Article
Zygomatic bone
The zygomatic bone (also known as zygoma or malar bone) is an important facial bone that forms the prominence of the cheek. It is roughly quadrangular in shape.
Gross anatomy
Zygoma has three surfaces, five borders, and two processes.
Surfaces
anterolateral surface is convex, pierced at its ...
Article
Frontal bone
The frontal bone is a skull bone that contributes to the cranial vault. It contributes to form part of the anterior cranial fossa.
Gross anatomy
The frontal bone has two portions:
vertical portion (squama): has external/internal surfaces
horizontal portion (orbital): has superior/inferior su...
Article
Frontal sinus
The frontal sinuses are the paranasal sinuses within the frontal bone. They are lined with mucosa and are most often two in number.
Summary
location: anterior frontal bones on either side of the midline behind the brow ridges
blood supply: supratrochlear, supraorbital and anterior ethmoidal a...
Article
Sphenoid sinus
The sphenoid sinus is the most posterior paranasal sinus.
Summary
location: the central body of the sphenoid bone anteroinferior to the sella turcica
blood supply: posterior ethmoidal and sphenopalatine arteries
innervation: posterior ethmoidal nerve and the orbital branch of the pterygopala...
Article
Ethmoidal air cells
The ethmoidal air cells, also known less commonly as the ethmoidal sinuses, form one of the four pairs of paranasal sinuses. They are located within the single, midline ethmoid bone.
Summary
location: between the orbit and the nasal cavity, within the ethmoid labyrinth of the ethmoid bone
blo...
Article
Maxillary sinus mucocele
Maxillary sinus mucoceles is a paranasal sinus mucocele in a maxillary sinus and is the least common location of all the paranasal sinus mucoceles.
Pathology
As with other mucoceles, maxillary sinus mucoceles are believed to form following obstruction of the sinus ostia, with resultant accumul...
Article
Acute sinusitis
Acute sinusitis (rare plural: sinusitides) is an acute inflammation of the paranasal sinus mucosa that lasts less than four weeks and can occur in any of the paranasal sinuses. If the nasal cavity mucosa is also involved - rhinitis - then the term rhinosinusitis may be used.
Clinical presentati...
Article
Subperiosteal abscess of the orbit
Subperiosteal abscess of the orbit occurs as a complication of adjacent infection such as orbital cellulitis or acute sinusitis.
Clinical presentation
Patients can present with pain, visual disturbance, proptosis and/or chemosis.
Pathology
Bacteria can extend via neurovascular foramina or bo...
Article
Subperiosteal abscess
Subperiosteal abscesses refer to the subperiosteal spread of infection characterized by purulent encapsulated fluid collections within the subperiosteal space.
Epidemiology
Subperiosteal abscesses are more often seen in children than in adults 1,2.
Associations
Subperiosteal abscesses have b...
Article
Pott puffy tumor
Pott puffy tumor refers to a non-neoplastic complication of acute sinusitis. It is characterized by a primarily subgaleal collection, subperiosteal abscess, and osteomyelitis. It is usually related to the frontal sinus but is sometimes secondary to mastoid pathology.
Rarer etiologies include tr...
Article
Multiple endocrine neoplasia type IIb
Multiple endocrine neoplasia (MEN) type IIb, also known as MEN type 3 (MEN3) 3 or mucosal neuroma syndrome 2, accounts for only 5% cases of MEN2 and is characterized by:
pheochromocytoma(s): in 50% of patients, often bilateral, and can be extra-adrenal
medullary thyroid cancer: 100% of patient...
Article
Postarthroscopic glenohumeral chondrolysis (PAGCL)
Postarthroscopic glenohumeral chondrolysis (PAGCL) is a rare complication of arthroscopic surgery in which there is rapid dissolution of articular cartilage with degenerative change of the glenohumeral articulation.
Epidemiology
PAGCL is more frequent in young people between 10 and 40 years, a...
Article
Posterior cranial fossa
The posterior cranial fossa is the most posterior aspect of the skull base housing the brainstem and cerebellum.
Gross anatomy
The following structures are present from anterior to posterior:
internal acoustic meatus
foramen magnum
groove for superior petrosal sinus
jugular foramen
hypogl...
Article
Caudothalamic groove
The caudothalamic groove is an important landmark when performing neonatal cranial ultrasound.
Gross anatomy
As the name suggests, it is located between the caudate nucleus and thalamus and is a shallow groove projecting from the floor of the lateral ventricle. It is approximately at the level...
Article
Focal nodular hyperplasia
Focal nodular hyperplasia (FNH) is a regenerative mass lesion of the liver and the second most common benign liver lesion (the most common is a hemangioma). Many focal nodular hyperplasias have characteristic radiographic features on multimodality imaging, but some lesions may be atypical in app...
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