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.

43 results found
Article

Anomalous insertion of the medial meniscus

Anomalous insertion of the medial meniscus (AIMM) is an anatomical variation of the insertion of the anterior root of the medial meniscus.   Terminology Defined as a congenital variation in the insertion of the anterior root of the medial meniscus onto the anterior cruciate ligament (ACL). The...
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Aubergine sign (penis)

The aubergine sign (also known as egg-plant sign or deformity) is a clinical sign of a fractured penis. Hemorrhage beyond the tunica albuginea produces swelling and bruising of the penis simulating the appearance of an aubergine.  
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Battle sign (base of skull fracture)

Battle sign is an eponymous term given to mastoid ecchymosis (bruising of the scalp overlying the mastoid process) and is strongly suggestive of a base of skull fracture, most commonly a petrous temporal bone fracture.  History and etymology Mr William Henry Battle (1855-1936) was an English s...
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Broken heart sign

The broken heart sign, also known as the Y sign in older otorhinolaryngology literature 2,3, describes the appearances of incudomalleolar disarticulation. This sign is identified on CT in the coronal plane, being formed by the widening of the incudomalleolar joint and lateral displacement of th...
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Burst lobe

A burst lobe is an uncommonly used description of traumatic lobar intraparenchymal hemorrhage of the brain that ruptures into the subdural space and communicates with subdural hemorrhage 1. As traumatic hemorrhages are more common in the frontal and temporal lobes, these lobes are the most affe...
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Costal hook sign (flail chest)

The costal hook sign is a chest x-ray feature seen in some cases of flail chest. It represents the rotation of a fractured rib along its long axis, something that is only possible if a second fracture is present along its length, even if the second fracture is not visible 1. 
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CT comma sign (head)

The CT comma sign is a characteristic sign seen in head trauma. It is the presence of concurrent epidural and subdural hematomas, which gives the characteristic appearance of this sign as a "comma" shape.
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Deep sulcus sign (chest)

The deep sulcus sign on a supine chest radiograph raises suspicion of a pneumothorax. On a supine plain chest film (common in intensive care units or as part of a trauma radiograph series), it may be the only suggestion of a pneumothorax because air collects anteriorly and basally, within the n...
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Deep sulcus sign (disambiguation)

The deep sulcus sign can refer to two different radiographic signs but is best known in the chest: deep sulcus sign (chest): of pneumothorax on supine CXR: deep sulcus sign (knee): better known as the lateral femoral notch sign of ACL injury
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Double delta sign (meniscal tear)

The double delta sign is a feature that has been described in a bucket handle meniscal tear when the inner meniscal fragment flipped anteriorly adjacent to the anterior horn of the donor site and is referred to as a displaced bucket handle tear. The original location of the posterior horn remain...
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Extracranial brain herniation

Extracranial or transcalvarial brain herniation refers to herniation of brain tissue external to the calvaria through a skull bone defect, which may be post-traumatic or post-surgical. Unlike encephaloceles, brain herniation is not surrounded by the meninges.  Craniectomy may be performed to de...
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Fallen lung sign

The fallen lung sign (also known as CT fallen lung sign) describes the appearance of collapsed lung away from the mediastinum encountered with tracheobronchial injury (in particular those >2 cm away from the carina). It is helpful to look for this rare but specific sign, in cases of unexplained ...
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Fleck sign (disambiguation)

The radiographic fleck sign refers to an avulsion fracture in the lower limb at either of two sites: fleck sign (ankle) due to superior peroneal retinaculum injury fleck sign (foot) due to Lisfranc injury
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Ice cream cone sign (disambiguation)

The ice cream cone sign may refer to: ice cream cone sign (middle ear ossicles) ice cream cone sign (vestibular schwannoma)
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Lightbulb sign (shoulder dislocation)

The lightbulb sign refers to the abnormal AP radiograph appearance of the humeral head in posterior shoulder dislocation. When the humerus dislocates it also internally rotates such that the head contour projects like a lightbulb when viewed from the front 1. See also light bulb sign (hepatic...
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Lipohemarthrosis

Lipohemarthrosis results from an intra-articular fracture with escape of fat and blood from the bone marrow into the joint, and is most frequently seen in the knee, associated with a tibial plateau fracture or distal femoral fracture; rarely a patellar fracture. They have also been described in ...
Article

Locked facet joint

Locked facet joint is a type of facet joint dislocation that results from jumping of the inferior articular process over the superior articular process of the vertebra below and becomes locked in the position. It can be unilateral or bilateral. Radiographic features Plain radiograph The tip ...
Article

Lung point sign

The lung point sign is a highly specific ultrasound sign of pneumothorax. It involves visualizing the point where the visceral pleura (lung) begins to separate from the parietal pleural (chest wall) at the margin of a pneumothorax.  In the absence of pneumothorax, the two pleural layers slide a...
Article

Molar tooth sign (disambiguation)

The molar tooth sign may refer to: molar tooth sign (CNS) molar tooth sign (abdomen)
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O'Donoghue unhappy triad

O'Donoghue unhappy triad or terrible triad often occurs in contact and non-contact sports, such as basketball, football, or rugby, when there is a lateral force applied to the knee while the foot is fixated on the ground. This produces an abduction-external rotation mechanism of injury ("pivot s...
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Orbital emphysema

Orbital emphysema is the presence of gas within the orbital soft tissues. It is usually due to orbital fractures communicating with the paranasal sinuses but can be caused by penetrating trauma and infection. It is a common finding also after orbital or ocular surgery.  Location preseptal pos...
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Pellegrini-Stieda lesion

Pellegrini-Stieda lesions are ossified post-traumatic lesions at (or near) the medial femoral collateral ligament adjacent to the margin of the medial femoral condyle. One presumed mechanism of injury is a Stieda fracture (avulsion injury of the medial collateral ligament at the medial femoral c...
Article

Pericardial fat tag sign (pneumothorax)

The pericardial fat tag sign is a sign of pneumothorax on supine CXR where the cardiac border has a lumpy contour. When gas is located in the pleural space between the lung and mediastinum, the pericardial fat is no longer compressed against the mediastinum and therefore can hang or dangle late...
Article

Pivot shift test

The pivot shift test forms part of the orthopedic examination of a post-traumatic knee. A positive test shows high specificity for injury of the anterior cruciate ligament. Procedure The pivot shift test is performed on a supine patient.  At the start the subject's knee is permitted to droop ...
Article

Pneumolipohaemarthrosis

Pneumolipohaemarthrosis is the presence of intra-articular gas in a lipohemarthrosis. It indicates an open intra-articular fracture. 
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Pneumothorax in supine projection

A pneumothorax does not display classical signs when a patient is positioned supine for a chest radiograph as commonly occurs in acute trauma or the critical care setting. Of course, pneumothoraces are common in both these scenarios and even relatively small pneumothoraces may be significant due...
Article

Pooping duck sign

Pooping duck sign indicates the presence of a triquetral fracture in a lateral wrist radiograph, where an avulsed fracture fragment from the dorsal cortex of the triquetrum projects along the dorsal aspect of the osseous structures of the wrist. In this sign, the fracture fragment represents th...
Article

Popeye sign

Popeye sign is a pronounced bulging muscle in the distal aspect of the biceps region of the arm. It is clinically apparent with a complete long head of biceps tendon tear which causes distal migration of the long head of biceps muscle.   Terminology Defined by the distal migration of the long ...
Article

Posterior fat pad sign (elbow)

The posterior fat pad sign is the visualization of a lucent crescent of fat located in the olecranon fossa on a true lateral view of an elbow joint with the elbow flexed at a right angle indicating an elbow joint effusion. Normally, the posterior fat pad will not be seen in this view.  In the s...
Article

Pronator quadratus sign

The pronator quadratus sign can be an indirect sign of distal forearm trauma. It relies on displacement of the fat pad that lies superficial to the pronator quadratus muscle. Pathology Displacement, anterior bowing, or obliteration of the fat plane in the setting of trauma may indicate a dista...
Article

Psoas sign (abdominal x-ray)

The psoas sign is a classic non-specific finding on the abdominal radiograph, potentially representing retroperitoneal pathology. Normally on an abdominal radiograph, the lateral margins of both the psoas muscles are clearly visible due to adjacent fat. When the lateral edge of one, or both, ps...
Article

Raccoon eyes sign (base of skull fracture)

Raccoon eyes sign (or panda eyes in the UK and Ireland) refers to periorbital ecchymosis with sparing of the tarsal plate 3 and is a physical examination finding indicative of a base of skull fracture of the anterior cranial fossa. However it is not pathognomonic for trauma, and there are sever...
Article

Round belly sign (abdominal compartment syndrome)

Round belly sign is a sign of increased abdominal pressure of greater than 20 mmHg in abdominal compartment syndrome where the abdomen has a rounded appearance of transverse section on CT, rather than its typical oval shape. The sign is positive when the AP to transverse diameter of the abdomen...
Article

Sail sign (elbow)

The sail sign on an elbow radiograph, also known as the anterior fat pad sign, describes the elevation of the anterior fat pad to create a silhouette similar to a billowing spinnaker sail from a boat. It indicates the presence of an elbow joint effusion. The anterior fat pad is usually conceale...
Article

Sandwich sign (disambiguation)

The sandwich sign is used for two different imaging appearances: sandwich sign (Marchiafava-Bignami disease) sandwich sign (mesentery) Sandwich sign has also been coined for the appearance of: primary pleural lymphoma 1,2 mediastinal lymphoma 3 marrow edema and hemorrhage on MRI of flexion...
Article

Seatbelt sign (abdomen)

The seatbelt sign is both a clinical and radiological sign. It is simply the presence of ecchymosis and/or abraded skin in the distribution of a seatbelt (i.e. horizontal and/or diagonal) extending across the abdomen evident after a motor vehicle accident. Epidemiology A positive abdominal sea...
Article

Segond fracture

Segond fracture is an avulsion fracture of the knee that involves the lateral aspect of the tibial plateau and is very frequently (~75% of cases) associated with disruption of the anterior cruciate ligament (ACL). On the frontal knee radiograph, it may be referred to as the lateral capsular sign...
Article

Seurat spleen

Seurat spleen is an angiographic appearance seen following blunt trauma to the spleen. Multiple small punctate regions of intraparenchymal contrast extravasation lead to a spotted appearance. Pathology Several mechanisms are thought to to attribute to this appearance which include sinusoidal s...
Article

Starfield pattern (fat embolism)

A starfield pattern has been described as being typical of DWI of patients with cerebral fat embolism 1,2. Although the term is closely linked to the diagnosis of fat embolism, it should be noted that such an appearance is merely the result of very numerous microemboli. As such, a similar patter...
Article

Straight left heart border sign

Straight left heart border sign is a recently described finding on chest radiograph. It is a fairly specific (84%) sign of hemopericardium after a penetrating chest trauma, although sensitivity at 40% is relatively poor. Positive predictive value (PPV) was found to be 89% 1. It is different to ...
Article

Tadpole sign

The tadpole sign, also known as the lollipop sign, refers to a characteristic morphology of post-traumatic bridging vein thrombosis with a rounded "head" and a tapering "tail". The finding demonstrates a high specificity for abusive head trauma, a sub-type of non-accidental injury, and should wa...
Article

Terry-Thomas sign

The Terry-Thomas sign refers to an increase in the scapholunate space on an AP radiograph of the wrist (or coronal CT). The increased distance indicates scapholunate dissociation (often with rotary subluxation of the scaphoid) due to ligamentous injury. There is no consensus as to what measureme...
Article

Yo-yo on a string sign (Stener lesion)

The yo-yo on a string sign denotes the characteristic appearance of the torn, proximally retracted and superficially displaced ulnar collateral ligament (UCL) due to a Stener lesion. Mechanism The sign occurs as a consequence of the tear of the ulnar collateral ligament of the thumb (gamekeepe...

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