Articles
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16,918 results
Article
Sacroiliitis
Sacroiliitis (rare plural: sacroiliitides) is an inflammation of one or both sacroiliac (SI) joints. It is a common cause of buttocks or lower back pain and can manifest as a wide range of disease processes.
Clinical presentation
Symptoms of sacroiliitis can vary. People with sacroiliitis comm...
Article
Sacroiliitis (differential)
Sacroiliitis (rare plural: sacroiliitides), an inflammation of the sacroiliac joint, can be a manifestation of a wide range of disease processes. The pattern of involvement is helpful for narrowing down the differential diagnosis.
Usually bilateral and symmetrical
enteropathic arthritis
Croh...
Article
Hamada classification of massive rotator cuff tears
The Hamada classification divides the x-ray features of massive rotator cuff tears into five grades. Subsequently, Walch subdivided grade 4 into two subtypes 1,2.
Classification
Hamada classification with Walch modification of rotator cuff tear arthropathy 1,3:
grade 1: acromiohumeral interva...
Article
Myxopapillary ependymoma
Myxopapillary ependymomas are a variant type of ependymoma that occurs predominantly in the filum terminale and/or conus medullaris. They represent 13% of all spinal ependymomas and are the most common tumors of the cauda equina region.
Epidemiology
They tend to have an earlier clinical presen...
Article
Multinodular and vacuolating neuronal tumor
Multinodular and vacuolating neuronal tumors (MVNT) are lesions with distinct cytoarchitectural patterns. They are often considered part of the heterogeneous group of tumors known as long-term epilepsy-associated tumors (LEATs).
Radiologically, MVNTs appear as small "bubbly" indolent subcortica...
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
Lymphangitic carcinomatosis
Lymphangitic carcinomatosis, or lymphangitis carcinomatosa, is the term given to tumor spread through the lymphatics of the lung and is most commonly seen secondary to adenocarcinoma.
Epidemiology
The demographics will reflect that of the underlying malignancy (see below).
Clinical presentati...
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
Neurofibromatosis type 1 (musculoskeletal manifestations)
Musculoskeletal manifestations of neurofibromatosis type 1 (NF1), or von Recklinghausen disease, are relatively common among these patients, with skeletal abnormalities occurring in up to 50% 1.
For a general discussion of the underlying condition, please refer to the article on neurofibromatos...
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
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
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...