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.

17 results found
Article

Q fever pneumonia

Q fever pneumonia refers to pulmonary infection with the organism Coxiella burnetii. It is sometimes classified as an atypical pneumonia. It can occur as either sporadic or outbreak cases. Clinical presentation The clinical picture is often dominated by fever, headaches and myalgias 5. A cough...
Article

Quad sign

The quad sign is a static sonographic sign observed in pleural effusion. It consists of four lines representing the pleural, rib, fluid and lung. Similar to the sinusoid sign, this sign has a high sensitivity and specificity for pleural effusion, which is anechoic in itself.
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Quadrangular space

The quadrangular space (or quadrilateral space) is one of two spaces located in the posterior compartment of the arm, along with the lateral triangular space.  Gross anatomy Boundaries anteriorly: subscapularis muscle posteriorly: teres minor muscle  medially: long head of triceps brachii m...
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Quadrangular space syndrome

Quadrangular space syndrome (QSS) is an uncommon diagnosis mainly because of lack of literature on the subject and possible misdiagnosis. Epidemiology QSS is present on ~1% of shoulder MRIs 6.  Clinical presentation Patients present with posterior shoulder pain and paresthesia over the later...
Article

Quadratus femoris muscle

The quadratus femoris muscle is the most inferior of the deep group of muscles in the gluteal region. It is a flat rectangular muscle below the obturator internus muscle and its associated gemellus superior and inferior muscles. Summary origin: lateral aspect of the ischium just anterior to t...
Article

Quadratus lumborum

The quadratus lumborum muscle is an irregular quadrilateral muscle that forms part of the posterior abdominal wall. Summary location: dorsal abdominal wall attachments: medial half of inferior margins of 12th ribs and upper four lumbar transverse processes blood supply:  branches of the lum...
Article

Quadratus plantae muscle

The quadratus plantae muscle acts to aid in flexing the 2nd to 5th toes. Summary origin: medial surface of calcaneus and lateral process of calcaneal tuberosity insertion: lateral side of tendon of flexor digitorum longus in proximal sole of the foot action: assists flexor digitorum longu...
Article

Quadriceps muscles

The quadriceps is the group of anterior thigh muscles that connect to the patella via the quadriceps tendon. The muscles are located: superficial: rectus femoris medial: vastus medialis lateral: vastus lateralis deep: vastus intermedius All four muscles are innervated by the femoral nerve. ...
Article

Quadriceps tendon

The quadriceps tendon is a thick tendon extending to the patella made up of contributions from all four quadriceps muscles. It classically has a trilaminar appearance: superficial layer: rectus femoris middle layer: vastus medialis, vastus lateralis deep layer: vastus intermedius See also q...
Article

Quadriceps tendon rupture

Rupture of the quadriceps tendon (QTR) is usually associated with forced flexion of the knee or a direct blow, although spontaneous ruptures are reported. Pathology Predisposing illnesses include:  connective tissue disorders  systemic lupus erythematosus rheumatoid arthritis gout renal i...
Article

Quadricuspid aortic valve

Quadricuspid aortic valve (QAV) is a rare cardiac valvular anomaly where there are four cusps, instead of the usual three, in the aortic valve. Epidemiology The estimated incidence on necropsy at ~1 in 8,000. While the incidence of QAV on 2D echocardiography has been reported to range between ...
Article

Quadrigeminal cistern

The quadrigeminal cistern (also known as superior cistern or cistern of the great cerebral vein) is one of the subarachnoid cisterns. It is located between the colliculi, the splenium of the corpus callosum and the superior surface of the cerebellum and extends from the third ventricle to the g...
Article

Quadrigeminal cistern lipoma

Quadrigeminal cistern lipomas make up approximately 25% of intracranial lipomas and are located within the quadrigeminal cistern. They may be associated with hypoplasia of the inferior colliculus or agenesis of the corpus callosum.  Please refer to the generic article on intracranial lipomas fo...
Article

Quadrigeminal plate

The quadrigeminal plate, also known as the tectal plate or just as tectum, is the portion of the midbrain tectum upon which the superior and inferior colliculi sit. The tectum is the dorsal portion of the midbrain (brainstem) and is derived in embryonic development from the alar plate of the ne...
Article

Quantitative computed tomography

Quantitative computed tomography (QCT) is a bone mineral density (BMD) measurement technique in which the CT scanner is calibrated using solid phantoms (made of calcium hydroxyapatite, representing various bone mineral densities) placed under the patient in a pad. With this calibration, the Houn...
Article

Quenching

Quenching refers to rapid expulsion of liquid cryogen used to maintain the MR magnet in superconducting state. Discussion Modern MRI scanners contain superconducting magnets which have very low energy consumption, made possible by maintaining internal subzero temperatures by way of a 'cryogen ...
Article

Quiz mode

Quiz mode presents multi-study cases in a way that is optimised for both presented tutorials and self-directed learning.  The cases shown will depend upon the system chosen and case ratings. We are planning to take into account many other (smarter) factors in the future.  Exclude from quiz mod...

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