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 16-40 cm/s 1.
In pathological situations, the flow velocity may decrease or even invert resulting in hepatofugal flow.
The flow waveform is usually smooth...
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
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
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
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...
Article
Perivertebral space
The perivertebral space is one of the deep compartments of the head and neck and includes the prevertebral space and paraspinal space.
Gross anatomy
The perivertebral space is a cylinder of soft tissue lying posterior to the retropharyngeal space and danger space surrounded by the prevertebral...
Article
Calcific tendinitis of the longus colli muscle
Calcific tendinitis of the longus colli muscles is an inflammatory/granulomatous response to the deposition of calcium hydroxyapatite crystals in the tendons of the longus colli muscle. It is sometimes more generically known as calcific prevertebral tendinitis or, less accurately, as retropharyn...
Article
Gallbladder
The gallbladder is a pear-shaped musculomembranous sac located along the undersurface of the liver. It functions to accumulate and concentrate bile between meals.
Gross anatomy
The normal adult gallbladder measures from 7-10 cm in length and 3-4 cm in transverse diameter 6. It communicates wit...
Article
Pleural effusion
Pleural effusions are abnormal accumulations of fluid within the pleural space. They may result from a variety of pathological processes which overwhelm the pleura's ability to reabsorb fluid.
Terminology
"Pleural effusion" is commonly used as a catch-all term to describe any abnormal accumula...
Article
Yellow nail syndrome
Yellow nail syndrome is a rare disorder principally affecting the lymphatic system.
Epidemiology
It is a rare disease with an approximate incidence of less than one million/year 8. There may be a slightly increased female predilection 5. While clinical onset varies from birth to late adult lif...
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