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.

21 results found
Article

Aubergine sign (penis)

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

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

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...
Article

Double delta sign

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...
Article

Extracranial brain herniation

Extracranial 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.  The herniated brain tissue requires surgical reducti...
Article

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 ...
Article

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...
Article

Lipohaemarthrosis

Lipohaemarthrosis 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

Nightstick fracture

Nightstick fractures are isolated fractures of the ulna, typically transverse and located in the mid-diaphysis and usually resulting from a direct blow. It is a characteristic defensive fracture when the patient tries to ward off an overhead blow from an assailant (or local law enforcement offic...
Article

Occult fracture

Occult fractures are those that are not visible on imaging, most commonly plain radiographs and sometimes CT, either due to lack of displacement or limitations of the imaging study. There may be signs of a fracture without one actually being seen. MRI or nuclear medicine studies are sometimes re...
Article

O'Donoghue unhappy triad

O'Donoghue unhappy triad or terrible triad often occurs in 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 the "pivot shift" mechanism. The O'Donoghue unhappy triad comprises three t...
Article

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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Pneumolipohaemarthrosis

Pneumolipohaemarthrosis is the presence of intra-articular gas in a lipohaemarthrosis. 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. Instead, the pneumothorax may be demonstrated by looking for the following signs: relative lucency of the involved hemithorax deep, sometimes tongue-like, costophrenic sulcus: deep sulcu...
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. Radiographic appearance Plain radiograph On lateral wrist radiographs, the pronator fat pad normally appears a thin ra...
Article

Sail sign (elbow)

The sail sign on an elbow radiograph 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 concealed within the coronoid fossa or seen parall...
Article

Seatbelt sign (abdomen)

The seatbelt sign is both a clinical and radiological sign. It is simply the presence of bruising/abrasions in the distribution of a seatbelt (i.e. horizontal and/or diagonal) across the abdomen, chest and sometimes neck.  A positive seatbelt sign, in combination with abdominal pain or tenderne...
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. History and etymology The term refers to a likeness between the angiographic appearance and the artwor...
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...

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