Articles
Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.
14,938 results found
Article
Anterior humeral circumflex artery
The anterior humeral circumflex artery is a vessel arising from the axillary artery at the proximal part of the arm. It is smaller in size relative to the posterior humeral circumflex artery.
Summary
origin: branch of the axillary artery at the proximal part of the arm
location: proximal arm...
Article
Anterior humeral line
The anterior humeral line is key to demonstrating normal elbow alignment and should be used whenever reading a pediatric elbow radiograph to exclude a subtle supracondylar fracture.
Measurement
A line drawn down the anterior surface of the humerus should intersect the middle third of the capit...
Article
Anterior inferior cerebellar artery
The anterior inferior cerebellar artery (AICA) is one of three vessels that provides arterial blood supply to the cerebellum. It has a variable origin, course and supply, with up to 40% of specimens not having an identifiable standard AICA. The amount of tissue supplied by the AICA is variable (...
Article
Anterior inferior cerebellar artery (AICA) infarct
Anterior inferior cerebellar artery (AICA) territory infarcts are much less common than posterior inferior cerebellar artery (PICA) infarcts. AICA generally arises from the caudal third of the basilar artery and supplies the lateral pons, inner ear, middle cerebellar peduncle and the anterior in...
Article
Anterior inferior iliac spine
The anterior inferior iliac spine (AIIS) is bony prominence on the anterior border of the ilium forming the superior border of the acetabulum.
Attachments include the Iliacus, origin of straight head of the rectus femoris, and also the proximal ileofemoral ligament (Y-ligament or ligament of Bi...
Article
Anterior inferior iliac spine avulsion injury
Anterior inferior iliac spine (AIIS) avulsion injuries are one of the six main types of pelvic apophyseal avulsion fractures. Subacute or chronic avulsion injuries can be mistaken for a pseudotumor.
Epidemiology
As with many pelvic avulsion injuries, they most often occur in adolescents (most...
Article
Anterior inferior tibiofibular ligament
The anterior inferior tibiofibular ligament (AITFL) is part of the lateral collateral ligament complex of the ankle.
Gross anatomy
It generally has a trapezoidal shape, with multiple bands of fibers that extends obliquely in a distal and lateral direction from the tibia to the fibula 1. It us...
Article
Anterior intercostal arteries
The intercostal spaces are supplied by pairs of posterior and anterior intercostal arteries.
Gross Anatomy
The 1st to 6th anterior intercostal arteries arise directly from the lateral aspect of the internal thoracic artery. The 7th to 9th arise from the musculophrenic artery, a branch of the i...
Article
Anterior interosseous artery
The anterior interosseous artery is one of the two branches of the short common interosseous artery (from the ulnar artery). The artery courses deep in the anterior compartment of the forearm on the anterior surface of the interosseous membrane along with the anterior interosseous nerve (from th...
Article
Anterior interosseous nerve
The anterior interosseous nerve also known as the volar interosseous nerve arises from the median nerve in the forearm, and supplies the flexor pollicis longus, pronator quadratus and the lateral portion of flexor digitorum profundus.
Gross anatomy
Origin
The anterior interosseous nerve conti...
Article
Anterior interosseous nerve syndrome
Anterior interosseous nerve syndrome (AINS), also known as Kiloh-Nevin syndrome, is one of three common median nerve entrapment syndromes; the other two being pronator teres syndrome and the far more common carpal tunnel syndrome.
Epidemiology
AINS is a rare entrapment syndrome, with comparati...
Article
Anterior jugular vein
The anterior jugular vein is a paired tributary of the external jugular vein.
Gross anatomy
Location
It arises beneath the chin in the region of the hyoid bone or suprahyoid neck.
Origin and course
The anterior jugular vein has its origin as the confluence of several small superficial subma...
Article
Anterior junction line
The anterior junction (or junctional) line is a feature of frontal chest radiographs and chest CTs. It is a result of the parietal and visceral pleura meeting anteromedially. It normally contains a small amount of fat but can form a stripe of variable thickness if there is a lot of fat present o...
Article
Anterior knee fat pads
There are three anterior knee fat pads 1:
infrapatellar fat pad (of Hoffa)
fills the space between the patella ligament and the anterior intercondylar area of the tibia 2
posterior suprapatellar (prefemoral or supratrochlear) fat pad
anterior suprapatellar (quadriceps) fat pad
fills the spa...
Article
Anterior knee pain
Anterior knee pain is common with a variety of causes which can be divided anatomically using a layered approach1 from superficial to deep:
Superficial soft tissues
prepatellar bursitis
Morel-Lavallée lesion
infrapatellar bursitis
Extensor mechanism
quadriceps tendinosis / partial tear
q...
Article
Anterior labroligamentous periosteal sleeve avulsion lesion
An anterior labroligamentous periosteal sleeve avulsion (ALPSA) lesion is similar to a Bankart lesion, in that it too is usually due to anterior shoulder dislocation and involves the anterior inferior labrum.
Epidemiology
It is often the result of chronic injury rather than acute dislocation;...
Article
Anterior lacrimal crest
The anterior lacrimal crest is a bony projection on the frontal process of the maxilla continuous with the orbital rim which creates the lateral margin of the lacrimal sac fossa. The medial palpebral ligament is attached to anterior lacrimal crest.
Immediately anterior to the anterior lacrimal ...
Article
Anterior lateral malleolar artery
The anterior lateral malleolar artery is the counterpart to the anterior medial malleolar artery, supplies the lateral aspect of the ankle.
Gross anatomy
Origin and course
branch of anterior tibial artery
runs posterior to the tendons of extensor digitorum longus and fibularis tertius to th...
Article
Anterior left perihepatic space
The anterior left perihepatic (or subhepatic) space is a potential space located between the diaphragm and the anterosuperior aspect of the left lobe of the liver.
Gross anatomy
The anterior left perihepatic space is separated from the posterior left perihepatic space by the left lobe of the ...
Article
Anterior left subphrenic space
The anterior left subphrenic space is a potential space between the fundus of the stomach and the left hemidiaphragm 1,2.
Gross anatomy
The anterior left subphrenic space is a subcompartment of the left supramesocolic space.
Boundaries
medial: falciform ligament (separates it from the anter...
Article
Anterior lenticonus
Anterior lenticonus is present when the anterior surface of the ocular lens assumes a conical shape.
Epidemiology
It can be unilateral or bilateral. Bilateral anterior lenticonus is associated with Alport syndrome.
Clinical presentation
Decreased visual activity and irregular refraction that...
Article
Anterior longitudinal ligament
The anterior longitudinal ligament (ALL) runs along the anterior surface of the vertebral bodies (firmly united to the periosteum) and intervertebral discs (attaching to the anterior annulus). It ascends from the anterosuperior portion of the sacrum superiorly to become the anterior atlantooccip...
Article
Anterior lumbar interbody fusion (ALIF)
Anterior lumbar interbody fusion (ALIF) is a spinal fusion procedure usually performed at L5/S1 or L4/5.
It is carried out either via a transabdominal or lateral retroperitoneal approach. A discectomy is performed, an interbody spacer introduced and fixed in place with screws with or without a...
Article
Anterior medial malleolar artery
Anterior medial malleolar artery is the counterpart to the anterior lateral malleolar artery, and supplies the medial aspect of the ankle.
Gross anatomy
Origin and course
branch of anterior tibial artery
arises approximately 5 cm proximal to the ankle
passes posterior to the tendons of exte...
Article
Anterior mediastinal germ cell tumors
Germ cell tumors are one of the causes of anterior mediastinal mass, and any of the germ cell histologies may be identified. They can therefore be divided histologically into:
seminoma
non-seminomatous germ cell tumors (NSGCT)
embryonal cell carcinoma
choriocarcinoma
yolk sac tumor
teratom...
Article
Anterior mediastinal mass in the exam
Getting a film with an anterior mediastinal mass in the exam is one of the many exam set-pieces that can be prepared for.
The film goes up and after a couple of seconds pause, you need to start talking:
CXR
There is a left sided mediastinal mass that makes obtuse angles with the mediastinal c...
Article
Anterior mediastinum
The anterior mediastinum is the portion of the mediastinum anterior to the pericardium and below the thoracic plane.
It forms the anterior part of the inferior mediastinum, and contains the thymus, lymph nodes, and may contain the portions of a retrosternal thyroid.
Related pathology
The comm...
Article
Anterior meningocele
Anterior meningocele is characterized by herniation of CSF-filled sac through a sacral anterior osseous defect. It is consistently found in the caudal regression syndrome.
It is in continuity with the thecal sac and lined by arachnoid and dura mater, but does not contain neural tissue.
Contrar...
Article
Anterior naris
The anterior (or external) nares (singular: naris) (or nostrils) form the entrance to the nose. Each naris is formed by a ring of structures:
medially the columella (soft tissue anteroinferior portion of the nasal septum)
laterally and superiorly the nasal ala
inferiorly the nasal sill
By vi...
Article
Anterior oblique ligament of the thumb
The anterior oblique ligament of the thumb is one of several carpometacarpal ligaments of the thumb and also one of its main stabilizers 1.
Terminology
The anterior oblique ligament of the thumb is also known as ‘beak ligament’. It can be divided into a superficial and a deep component and som...
Article
Anterior pararenal space
The anterior pararenal space is the portion of the retroperitoneum that lies between the posterior surface of the parietal peritoneum and the anterior reflection of the perirenal fascia.
Gross anatomy
It contains the duodenum (D2 & D4), pancreas and retroperitoneal segments of the ascending an...
Article
Anterior perforated substance
The anterior perforated substance, or substantia perforata anterior, is an area in the basal forebrain that plays an important role with regards to the blood supply of deep grey matter structures of the brain.
Gross anatomy
Located within the basal forebrain, the anterior perforated substance...
Article
Anterior pituitary
The anterior pituitary (or adenohypophysis) is by far the largest part of the pituitary gland, and is responsible for synthesis and release of most pituitary hormones (with the exception of oxytocin and antidiuretic hormone (ADH) which are released by the posterior pituitary).
It consists of 3 ...
Article
Anterior pontine membrane
The anterior pontine membrane is an arachnoid membrane located anteriorly in the posterior fossa to the side of the basilar artery, separating the prepontine cistern (medially) form the cerebellopontine cistern (laterally) 1.
The abducens nerve (CN VI) travels within the membrane as it ascends...
Article
Anterior ramus of the lateral sulcus
The anterior ramus of the lateral sulcus, is located at the very anterior end of the lateral sulcus (sylvian fissure), just anterior to the ascending ramus, and passes superiorly into the inferior frontal gyrus separating the pars orbitalis form the pars triangularis of the frontal operculum.
...
Article
Anterior resection syndrome
Anterior resection syndrome refers to wide spectrum of symptoms which develop post-sphincter preserving rectal resection for rectal cancer.
Pelvic radiotherapy is a known risk factor to develop anterior resection syndrome.
Epidemiology
There have been reports that up to 47% of patients who un...
Article
Anterior right subhepatic space
The anterior right subhepatic space is a potential space between the inferior surface of the right lobe of the liver and the transverse colon.
Gross Anatomy
The anterior right subhepatic space is separated from Morison’s pouch (also known as the posterior right subhepatic space) by the transve...
Article
Anterior sacral meningocele
Anterior sacral meningocele is a congenital defect seen in the anterior aspect of the spine. It is defined as a meningeal cyst that occurs in the presacral space secondary to agenesis of a portion of the anterior sacrum.
Pathology
Associations
In approximately 50% of cases, associated malform...
Article
Anterior shoulder capsular insertion
The anterior capsular insertion, unlike the posterior aspect of the shoulder joint capsule which has a constant scapular attachment along the margins of the glenoid labrum, inserts a variable distance from the labrum.
The capsular insertions are classified as follows:
type I: at or very near t...
Article
Anterior shoulder dislocation
Anterior shoulder dislocation is by far the commonest type of dislocation and usually results from forced abduction, external rotation and extension 1.
Epidemiology
Broadly speaking, anterior shoulder dislocations occur in a bimodal age distribution. The first, and by far the more prevalent a...
Article
Anterior spinal artery
The anterior spinal artery supplies the anterior portion of the spinal cord and arises from the vertebral artery in the region of the medulla oblongata. The two vertebral arteries (one of which is usually bigger than the other) anastamose in the midline to form a single anterior spinal artery at...
Article
Anterior spinal commissure
The anterior spinal commissure connects the left and right sides of the spinal cord anteriorly. It is located between the posterior-most extent of the anterior median fissure anteriorly and the ventral grey matter commissure posteriorly 1.
It is composed of anterior and lateral spinothalamic t...
Article
Anterior spinothalamic tract
The anterior spinothalamic tract, also known as the ventral spinothalamic fasciculus, is an ascending pathway located anteriorly within the spinal cord, primarily responsible for transmitting coarse touch and pressure.
The lateral spinothalamic tract (discussed separately), in contrast, primar...
Article
Anterior subluxation of the cervical spine
Anterior subluxation of the cervical spine, also known as hyperflexion sprain, is a ligamentous injury of the cervical spine.
Clinical presentation
Patients present with severe, focal neck pain. There may be neurological symptoms due to spinal cord injury.
Pathology
Anterior subluxation of t...
Article
Anterior superior alveolar canal
The anterior superior alveolar canal courses through the anterior wall of the maxillary sinus, and contains the anterior superior alveolar nerve, artery and vein. Usually, it shares a common channel with the infraorbital canal but when seen separately should not be confused for a fracture.
Article
Anterior superior alveolar nerve
The anterior superior alveolar nerve, also known as the anterior superior dental nerve, is the third branch of the infra-orbital nerve, from the maxillary division of the trigeminal nerve. It is the largest of the superior alveolar nerves and contributes to the superior dental plexus.
Gross an...
Article
Anterior superior iliac spine
The anterior superior iliac spine is an important bony surface landmark and is the prominence is the most anterior part of the ilium. It can be palpated at the lateral end of the inguinal fold. Attachments include the inguinal ligament, sartorius muscle and depending on which resource you read, ...
Article
Anterior superior iliac spine avulsion injury
Anterior superior iliac spine (ASIS) avulsion injuries typically occur in athletes during forceful muscular contraction. The anterior superior iliac spine is the site of attachment for sartorius and tensor fascia latae muscles.
Pathology
Anterior superior iliac spine avulsion, like other pelv...
Article
Anterior talofibular ligament
The anterior talofibular ligament (ATFL) is part of the lateral collateral ligament complex of the ankle. Its role is to stabilize the talus. It is also the weakest of the lateral collateral ankle ligaments.
Gross anatomy
The ATFL is an intracapsular flat two-banded ligament that arises from ...
Article
Anterior talofibular ligament injury
Anterior talofibular ligament injury is the most common of the ligament injuries that can occur as part of the lateral ligament complex injuries 2. The injuries can comprise either soft tissue tears, avulsion fractures or both.
Pathology
Anterior talofibular ligament injuries typically occur w...
Article
Anterior temporal artery
The anterior temporal artery is usually a branch of the M1 segment of the middle cerebral artery (MCA) that curves out of the Sylvian fissure and runs over the temporal lobe to supply the anterior third of the superior, middle and inferior temporal gyri.
Variant anatomy
The temporopolar arter...
Article
Anterior temporal lobe perivascular spaces
Anterior temporal lobe perivascular spaces are recently recognized special variants of tumefactive perivascular spaces, which can mimic cystic tumors with surrounding edema.
Epidemiology
A predilection for women has been reported 1. Age range is wide, from 24 to 86 years old reported 1.
Clini...
Article
Anterior tibial artery
The anterior tibial artery is the main arterial supply of the anterior compartment of the leg.
Gross anatomy
The anterior tibial artery arises from the popliteal artery in the popliteal fossa and continues distally as the dorsalis pedis artery.
Course
The popliteal artery usually divides at...
Article
Anterior tibial translocation sign
The anterior tibial translocation sign or anterior drawer sign (a.k.a. anterior translation of tibia) is seen in cases of complete rupture of the anterior cruciate ligament and refers to anterior translocation (anterior tibial subluxation) of the tibia relative to the femur of >7 mm 1. It measur...
Article
Anterior tibial vein
The anterior tibial veins, continuations of the venae comitantes of the dorsalis pedis artery, leave the anterior compartment of the leg between the tibia and fibula and pass through the proximal end of the interosseous membrane. They unite with the posterior tibial veins to form the popliteal v...
Article
Anterior tibiotalar ligament
The anterior tibiotalar ligament (ATTL) is the weaker of the deep components of the deltoid ligament 1,2.
Gross anatomy
The anterior tibiotalar ligament is covered by the tibionavicular and tibiospring ligaments. It is a short and thin ligament which connects the medial tibial malleolus to the...
Article
Anterior triangle
The anterior triangle forms the anterior compartment of the neck and is separated from the posterior triangle by the sternocleidomastoid muscle. The triangles of the neck are surgically focused, first described from early dissection-based anatomical studies which predated cross-sectional anatomi...
Article
Anterior tympanic artery
The anterior tympanic artery is the second named branch of the first part of the maxillary artery. The vessel passes through the petrotympanic fissure to supply the tympanic membrane and lining of the middle ear. It accompanies the chorda tympani and the anterior ligament of malleus in its course.
Article
Anterior ulnar recurrent artery
The anterior ulnar recurrent artery is a recurrent branch of the proximal ulnar artery that ascends in the anterior medial aspect of the elbow, anterior to the medial epicondyle of the humerus to anastomose with the inferior ulnar collateral artery (from the brachial artery) and contribute to th...
Article
Anterior vertebral body beaking
Anterior vertebral body beaking occurs in a number of conditions and may emanate from the central portion or the lower third of the vertebral body.
Middle third
Morquio syndrome 1 (middle for Morquio)
Lower third
Hurler syndrome 2
achondroplasia 3
pseudoachondroplasia 4
cretinism 5
Down ...
Article
Anterolateral impingement of the ankle
Anterolateral ankle impingement is one of the impingement syndromes of the ankle and can occur as a posttraumatic sequel of an inversion injury 1-6.
Terminology
Anterolateral ankle impingement has been known under the term anterolateral 'meniscoid lesion', which is the result of synovitis in t...
Article
Anterolateral ligament of the knee
The anterolateral ligament of the knee (ALL) is a ligament that is thought to aid with rotational stability of the knee joint. Some think that its presence (or reconstruction) may result in better outcomes from ACL stabilization surgery 2.
Gross anatomy
origin: prominence of the lateral femora...
Article
Anterolateral recess of the ankle joint
The anterolateral recess of the ankle joint also known as the anterolateral gutter is a triangular or pyramidal formed topographical space of the anterolateral aspect of the ankle 1-4.
Gross anatomy
The space may contain joint fluid in asymptomatic individuals and is defined by the following a...
Article
Anterolisthesis
The term anterolisthesis refers to anterior displacement (forward slip) of a vertebral body relative to the one below.
Its severity can be graded by the Meyerding classification and its etiology classified according to the Wiltse classification.
Article
Anteromedial impingement of the ankle
Anteromedial impingement of the ankle is one of the ankle impingement syndromes and can occur as late effect of a traumatic injury 1-3.
Epidemiology
It is one of the less common ankle impingement syndromes 2. It can occur as a result of a previous plantar flexion and inversion injury and can b...
Article
Anterosuperior mediastinal mass (mnemonic)
The common causes of an anterosuperior mediastinal mass can be remembered by using the mnemonic:
5 Ts
Mnemonic
T: thymus
T: thyroid
T: thoracic aorta
T: terrible lymphoma
T: teratoma and germ cell tumors - see mediastinal germ cell tumors
Testicular cancer metastasis can represent a sixt...
Article
Anthrax
Anthrax is a zoonosis caused by Bacillus Anthracis. There are four types of anthrax: inhalational anthrax (also known as woolsorter's disease and ragsorter's disease), cutaneous anthrax, injection anthrax and intestinal anthrax.
Epidemiology
The disease burden of anthrax decreased so dramatica...
Article
Antibiotic-associated diarrhea
Antibiotic-associated diarrhea can be broadly divided into two groups:
Clostridioides difficile colitis
non-specific diarrhea
The former is a life-threatening condition, requiring prompt diagnosis and treatment whereas the later is milder and self-limiting.
Both result from changes in the b...
Article
Antibiotic beads
Implanted antibiotic beads are a form of microbiological treatment inserted during orthopedic procedures to aid with the treatment of chronic infection. They are also used as a local treatment for osteomyelitis.
The beads are radiopaque, thus lending themselves to visualization on all imaging m...
Article
Antibiotic joint spacer
Antibiotic joint spacers are temporary intra-articular devices with the main aim to control predominantly post-arthroplasty joint and bone infections via sustained, topical antibiotic release, whilst also ensuring reasonable joint function.
Antibiotic spacers are typically made of poly(methyl ...
Article
Antiglide plate fixation
Antiglide plate fixation is an open reduction internal fixation (ORIF) technique used in oblique diaphyseal fractures of the distal fibular.
Usage
They are used to counteract vertical shear forces during axial loading in the diaphyseal bone and to prevent sliding/shortening of the fracture fr...
Article
Anti-GQ1b IgG antibody syndrome
Anti-GQ1b IgG antibody syndrome refers to a number of conditions which share autoantibodies to the ganglioside complex GQ1b, and have overlapping clinical spectrums.
The conditions believed to represent various clinical manifestations of a common immunological disorder include 1:
acute ophth...
Article
Anti-Jo-1 antibody positive interstitial lung disease
Anti-Jo-1 antibody positive interstitial lung disease refer to cases of interstitial lung disease occurring in the setting on anti-Jo-1 antibody positivity.
Pathology
Anti-Jo-1 antibody positivity has a recognized association with interstitial lung disease. This most commonly occurs in a setti...
Article
Anti melanoma differentiation associated gene 5 (MDA5) antibody positive clinically amyopathic dermatomyositis
Anti-MDA5 antibody-positive amyopathic dermatomyositis is a subtype of dermatomyositis where there is positivity to an anti-melanoma differentiation-associated gene 5 (MDA5) antibody. It has been reported to be associated with rapidly progressive interstitial lung disease (RP-ILD) resulting in h...
Article
Anti-MOG associated encephalomyelitis
Anti-MOG associated encephalomyelitis represents a group of inflammatory demyelinating disorders united by the presence of IgG antibodies to myelin oligodendrocyte glycoprotein (MOG) that overlap but are distinct from acute disseminated encephalomyelitis (ADEM), neuromyelitis optica spectrum dis...
Article
Antimuscarinics in MRI protocols
Antimuscarinics decrease bowel movements in pelvic MRI, and may be used for better image acquisition.
Usually, 20mg of hyoscine butylbromide IM/IV is administered prior to examination.
Contraindications
Myasthenia gravis
Pyloric stenosis
Benign prostatic hyperplasia
Paralytic ileus
Additi...
Article
Antineutrophil cytoplasmic antibody
Antineutrophil cytoplasmic antibodies (ANCAs) are a heterogenous class of IgG autoantibodies raised against the cellular contents of neutrophils, monocytes and endothelial cells 1. Under indirect immunofluorescence (IIF) microscopy, three ANCA staining patterns are observed, based on the varying...
Article
Anti-neutrophil cytoplasmic antibody associated vasculitides
Anti-neutrophil cytoplasmic antibody (ANCA) - associated vasculitides refer to a group of heterogeneous autoimmune diseases characterized by necrotizing vasculitides and positive ANCA titers. They are reactive to either proteinase-3 (PR3-ANCA) - cANCA or myeloperoxidase (MPO-ANCA) - pANCA. These...
Article
Anti-N-methyl-D-aspartic acid receptor encephalitis
Anti N-methyl-D-aspartic acid (NMDA) receptor encephalitis is an autoimmune encephalitis with antibodies against the NMDA receptors. It is sometimes considered a form of autoimmune limbic encephalitis. It usually affects young patients particularly young females, in about 60% of whom ovarian ter...
Article
Antinuclear antibody
Antinuclear antibodies (ANAs) are a heterogenous class of autoantibodies raised against antigens present in the cell nucleus, including nucleic acids themselves and the enzymes involved in their processing. Under indirect immunofluorescence (IIF) microscopy, four major ANA staining patterns are ...
Article
Antiphospholipid syndrome
Antiphospholipid syndrome is a systemic autoimmune disorder. It is usually defined as the clinical complex of vascular occlusion and ischemic events occurring in patients who have circulating antiphospholipid antibodies.
Clinical presentation
Antiphospholipid syndrome is characterized by venou...
Article
Antiphospholipid syndrome (pulmonary manifestations)
Pulmonary involvement in antiphospholipid syndrome is one of the most frequent arterial complications of antiphospholipid syndrome.
Pathology
It is essentially related to pulmonary arterial microthrombosis and may cause a wide spectrum of conditions, which include 3-5:
pulmonary thromboembol...
Article
Anti-synthetase syndrome
Anti-synthetase syndrome (ASS) is a systemic, inflammatory, autoimmune disease that is characterized by inflammatory myositis, polyarthritis associated with interstitial lung disease (ILD), and anti-synthetase autoantibodies.
Pathology
Anti-synthetase syndrome can result from autoantibodies to...
Article
Antithrombin III deficiency
Antithrombin (AT) III deficiency (now simply called antithrombin deficiency) refers to a congenital lack of the endogenous anticoagulant antithrombin.
Epidemiology
Antithrombin deficiency is considered the least common of the three main anticoagulant deficiencies (the other two being protein C...
Article
Antler sign (lung)
The antler sign is an uncommon sign of lung torsion on CT where branches from the main pulmonary artery all arise from a single side, indicating twisting of the lobe or lung.
In the normal lung, the main pulmonary arteries are straight and lobar and segmental branches arise from it on both side...
Article
Antley-Bixler syndrome
Antley-Bixler syndrome (ABS), also known as trapezoidocephaly-synostosis syndrome, is a rare autosomal dominant or recessive condition characterized by craniosynostosis and extra-cranial synostoses. Mid-facial hypoplasia is also common.
Epidemiology
It is a very rare condition with only 50 cas...
Article
Antoine Henri Becquerel
Antoine Henri Becquerel (1852-1908) was a French scientist renowned for his work and subsequent discovery of radioactivity for which he was awarded the Nobel Prize for physics in 1903.
Early life
Antoine Henri Becquerel was born on 15 December 1852 in Paris, France to a family of nobility and ...
Article
Antonio Egas Moniz
Antonio Egas Moniz (1874-1955) 1 was a pioneering Portuguese neurologist that is notable in radiology history for his development of cerebral angiography in 1927.
He is also known as the developer of prefrontal leucotomy (now better known as a lobotomy) for which he received a Nobel Prize in 1...
Article
Antopol-Goldman lesion
Antopol-Goldman lesions are very rare presentations of subepithelial hemorrhage in the renal pelvis, presenting as discrete mass-like hematomas.
Pathology
The cause of these lesions is uncertain, although long-term anticoagulation, non-steroidal anti-inflammatory drugs (NSAIDs) overuse, trauma...
Article
Antral follicle count
Antral follicle count (AFC) or basal antral follicle count is a test performed to check a female individual's ovarian reserve.
Principle
A female is born with a lifetime supply of eggs and as she enters puberty these eggs develop. During and after puberty these follicles develop and are relea...
Article
Antral nipple sign (pyloric stenosis)
The antral nipple sign refers to redundant pyloric mucosa protruding into the gastric antrum and is seen in hypertrophic pyloric stenosis on ultrasound examination.
See also
cervix sign (pyloric stenosis)
target sign (pyloric stenosis)
Article
Antral pad sign
The antral pad sign is a feature seen on a spot radiograph of the upper gastrointestinal tract obtained with orally-administered contrast material. It refers to the extrinsic impression or indentation on the posteroinferior aspect of the antrum. The impression is generally arcuate and smooth, an...
Article
Antrochoanal polyp
Antrochoanal polyps (ACP) are solitary sinonasal polyps that arise within the maxillary sinus. They pass to the nasopharynx through the sinus ostium and posterior nasal cavity, enlarging the latter two.
Similar, less common, polyps can arise in the sphenoid sinus extending into the nasopharynx:...