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.

578 results found
Article

Uncal herniation

Uncal herniation is a subtype of transtentorial downward brain herniation that involves the uncus, usually related to cerebral mass effect increasing the intracranial pressure. Clinical presentation pupils and globe clinical features 3 initially, an ipsilateral dilated pupil that is unrespons...
Article

Unilateral facet dislocation

Unilateral facet dislocation is a relatively stable type of facet dislocation. Pathology Mechanism Flexion/distraction associated with rotation. The inferior articular facet of vertebral above moves over the superior facet of the vertebral below and becomes locked. It usually affects C4-C5 or...
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Upper extremity dislocations

Upper extremity dislocations are relatively common on account of the great range of motion the upper limb is capable of (a general principle is that the greater the range of motion of a joint, the more prone it is to dislocation). In many instances dislocations are associated with fractures eith...
Article

Ureteric injury

Ureteric injury is a relatively uncommon, but severe event, which may result in serious complications as a diagnosis is often delayed.  Clinical presentation Ureteric injuries unreliably demonstrate macro- or micro-scopic hematuria as it may be absent in up to 25% of patients 5, 6. Classic cli...
Article

Urethral injury

Urethral injuries can result in long-term morbidity and most commonly result from trauma. The male urethra is much more commonly injured than the female urethra and is the focus of this article. Clinical presentation In the setting of trauma, the classic triad of blood of the external urethral...
Article

Urinary bladder rupture

Urinary bladder rupture is usually seen in the context of significant trauma. Pathology Etiology Bladder rupture can be categorized into five types depending on the location and extent of the rupture: Bladder contusion This is commonly seen but sometimes not classed as true rupture, since i...
Article

Urinothorax

Urinothorax (plural: urinothoraces), also known as urothorax, is a rare cause of pleural effusion due to the accumulation of urine within the pleural space. Clinical presentation Patients present with varying degrees of respiratory distress depending on the amount of fluid that has accumulated...
Article

Vacuum assisted therapy

Vacuum-assisted therapy, also known vacuum-assisted closure (VAC) or negative pressure wound therapy, refers to a device used in the treatment of acute or chronic wounds.  Components foam dressing applied on the wound suction drains covering transparent adhesive membrane vacuum source: VAC ...
Article

Vancouver classification of periprosthetic hip fractures

The Vancouver classification of periprosthetic hip fractures proposed by Duncan and Masri is the most widely used classification system. It takes into account the fracture site, the status of the femoral implant, and the quality of surrounding femoral bone stock. type A: fractures involve the t...
Article

Vitreous hemorrhage

Vitreous hemorrhage refers to bleeding into the vitreous chamber. Epidemiology Vitreous hemorrhage has an incidence of approximately 7 in 100000 1,2.   Clinical presentation The most common clinical presentation is with sudden, painless visual loss to varying degrees of severity 2. Associate...
Article

Volar intercalated segment instability

Volar intercalated segment instability (VISI) is a type of instability involving the wrist. It is less often encountered than dorsal intercalated segment instability (DISI). Clinical presentation It presents in most cases with nonspecific wrist pain and a "clunking" on the ulnar deviation of t...
Article

Volar locking plate

Volar locking plates or distal volar radial anatomical plates are the most commonly used metallic device in the open reduction and internal stabilization of distal radius fractures. These devices allow immediate postoperative return of motion, and are good at preventing angular displacement. The...
Article

Volar plate avulsion injury

Volar plate avulsion injuries are a type of avulsion injury. The volar plate of the proximal interphalangeal (PIP) joint is vulnerable to hyperextension injury, in the form of either a ligament tear or an intra-articular fracture. Gross anatomy The volar plate forms the floor of the PIP joint ...
Article

Weber classification of ankle fractures

The Weber ankle fracture classification (or Danis-Weber classification) is a simple system for classification of lateral malleolar fractures, relating to the level of the fracture in relation to the ankle joint, specifically the distal tibiofibular syndesmosis. It has a role in determining treat...
Article

Wedge fracture

Wedge fractures (also known as compression fractures) are hyperflexion injuries to the vertebral body resulting from axial loading. Most commonly affecting the anterior aspect of the vertebral body, wedge fractures are considered a single-column (i.e. stable) fracture.  Less commonly wedge frac...
Article

Whiplash syndrome

Whiplash syndrome, also known as whiplash-associated disorders (WAD), are the various symptoms caused by rapid acceleration and/or deceleration injuries, which result in cervical sprain or strain. Epidemiology Whiplash is a common injury, usually associated with motor vehicle collisions 1-5. T...
Article

Winquist classification of femoral shaft fractures

The Winquist classification of femoral shaft fractures is based on fracture comminution and was proposed by Winquist in 1980. This classification is used with regards to management decision making, in determining whether a fracture requires an intramedullary nail or open reduction.  Type 0: no ...
Article

Young and Burgess classification of pelvic ring fractures

The Young and Burgess classification is a modification of the earlier Tile classification 1. It is the recommended 5 and most widely used classification system for pelvic ring fractures. It takes into account force type, severity, and direction, as well as injury instability. Three basic mech...
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...
Article

Zygomaticomaxillary complex fracture

Zygomaticomaxillary complex (ZMC) fractures, also known as tripod, tetrapod, quadripod, malar or trimalar fractures, are seen in the setting of traumatic injury to the face. They comprise fractures of the: zygomatic arch inferior orbital rim, and anterior and posterior maxillary sinus walls l...

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