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.

2,678 results found
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Upper limb anatomy

Upper limb anatomy encompasses the anatomy of the shoulder, arm, elbow, forearm, wrist and hand.
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Upper limb radiography

Upper limb radiography is the radiological investigation of the shoulder girdle, humerus, ulna, radius, carpals and metacarpals of the hand. It is often utilised in the context of trauma to rule out fractures and dislocations. 
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Upper subscapular nerve

The upper subscapular nerve, also known as the short or superior subscapular nerve, arises from the posterior cord of the brachial plexus and supplies the subscapularis muscle. Gross anatomy Origin The upper subscapular nerve branches from the posterior cord of the brachial plexus with fibres...
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Vacuum phenomenon in shoulder

Vacuum phenomenon in the shoulder refers to the presence of intra-articular gas in the shoulder joint. It is a very common occurrence, particularly in external rotation. This can cause circular or linear areas of low signal intensity on GRE MR images of the shoulder obtained with external rotati...
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Valgus vs varus

The terms valgus and varus refer to angulation (or bowing) within the shaft of a bone or at a joint. It is determined by the distal part being more medial or lateral than it should be. Whenever the distal part is more lateral, it is called valgus. Whenever the distal part is more medial, it is ...
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Van Buchem disease

Van Buchem disease (VBD) is an extremely rare hereditary sclerosing bone dysplasia, also known as hyperostosis corticalis generalisata. This disease is characterised most notably by mandibular enlargement and thickening of the skull. Epidemiology Less than 30 cases have been reported in the li...
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Vancouver classification

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...
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Vastus intermedius muscle

The vastus intermedius muscle is one of the 4 quadriceps muscles in the anterior compartment of the thigh. The others are the vastus medialis, the vests laterals, and the rectus femoris. Summary origin: upper two thirds of the anterior and lateral surfaces of the femur insertion quadriceps t...
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Vastus lateralis muscle

The vastus lateralis is largest of the four quadriceps muscles in the anterior compartment of the thigh. The others are the rectus femoris, the vastus intermedius, and the vastus medialis. Summary origin femur lateral part of intertrochanteric line margin of greater trochanter lateral mar...
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Vastus medialis muscle

The vastus medialis muscle is one of the four quadriceps muscles in the anterior compartment of the thigh. The others are the rectus femoris, the vastus intermedius, and the vastus lateralis. Summary origin femur medial part of intertrochanteric line pectineal line medial lip of the linea ...
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Vertebra

The vertebra (plural: vertebrae) is the fundamental segmental unit of the vertebral column (also know as the spine). Gross anatomy Vertebrae, apart from those that are atypical, have a similar basic structure which can be described as an anterior vertebral body and a posterior neural (or verte...
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Vertebral anomalies

The vertebral column is affected by a range of anatomical variants of the body and/or neural arch as well as accessory ossicles. Knowledge of basic vertebral anatomy and ossification is essential for describing and understanding the range of anomalies. Variant anatomy Vertebral body hemiverte...
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Vertebral body mass

The differential diagnosis for a vertebral body mass is broad and may range from a completely benign, sclerotic enostosis (bone island) to a malignant primary bone tumour. Classification Broadly, these lesions can be separated into: non-neoplastic lesions primary bone tumours secondary meta...
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Vertebral body squaring (differential)

Vertebral body squaring refers to the loss of normal concavity of the anterior border. It is seen in a variety of conditions including:  Differential diagnosis Ankylosing spondylitis Ankylosing spondylitis is the most common cause of vertebral body squaring. It usually involves multiple level...
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Vertebral haemangioma

Vertebral haemangiomas are the most common benign vertebral neoplasms. They are usually asymptomatic and incidentally detected due to their characteristic features on imaging for other reasons. Please refer on the article on primary intraosseous haemangioma for a general discussion in this enti...
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Vertebral lesion (differential)

Differential diagnosis of vertebral lesions includes:  Lesion originating in vertebral body  intraosseous haemangioma metastases Paget disease multiple myeloma Osteonecrosis vertebral body osteomyelitis lymphoma plasmacytoma giant cell tumour Langerhans cell histiocytosis fibrous dys...
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Vertebral metastases

Vertebral metastases represent the secondary involvement of the vertebral spine by haematogenously-disseminated metastatic cells. They must be included in any differential diagnosis of a bone lesion in a patient older 40 years. This article will focus only on the metastasis involving the bony s...
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Vertebral pneumatocyst

Vertebral pneumatocysts refers to the presence of a gas-filled cavity within the vertebrae, more prevalent on the cervical spine. Intraosseous pneumatocysts are more common adjacent to the sacroiliac joint while it is rare in the vertebral column. Other causes of vertebral gas e.g. Kümmell disea...
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Vertebral scalloping

Vertebral scalloping is a concavity to the posterior (or less commonly anterior) aspect of the vertebral body when viewed in a lateral projection. A small amount of concavity is normal, as is concavity of the anterior vertebral body (see vertebral body squaring). Posterior scalloping Causes of...
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Vertebral vascular foramen

Vertebral vascular foramina are normal findings seen on cross-sectional imaging and should not be mistaken for a fracture, especially in the setting of trauma. They transmit: basivertebral veins (forms Hahn's canal): foramen is seen on the posterior surface of the vertebral body in the midline...
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Vertebra plana

Vertebra plana (a.k.a. pancake / silver dollar / coin-on-edge vertebra) is the term given when a vertebral body has lost almost its entire height anteriorly and posteriorly, representing a very advanced compression fracture. Plural is vertebrae planae. It can occur in a variety of settings, incl...
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Vertebra plana (mnemonic)

Mnemonics to remember the causes of vertebra plana include: IMELT FETISH Mnemonics IMELT I: infection M: metastasis/myeloma E: eosinophilic granuloma L: lymphoma/leukaemia T: trauma; tuberculosis FETISH F: fracture (trauma) E: eosinophilic granuloma T: tumour (e.g. metastases, myelo...
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Vertebra prominens (C7)

C7, also called vertebra prominens, is the seventh cervical vertebra and looks like vertebrae C3-C6, but has some distinct features making it an atypical vertebrae. The name vertebra prominens arises from its long spinous process, which is easily palpable.  Gross anatomy C7 possesses the stand...
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Vertebroplasty

Vertebroplasty is an imaging-guided procedure which entails percutaneous injection of surgical polymethylmethacrylate (PMMA) cement into a diseased vertebral body. Vertebroplasty provides pain relief and strengthening of the bone of vertebrae weakened by disease. Indications It can be used as ...
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Very bizarre generalised lesions of bone (differential)

Very bizarre generalised lesions of bone tend to make you exclaim "Oh my! What is going here?"  Although there are numerous potential causes, in this situation it is worth thinking of a number of entities: skeletal dysplasias and metabolic diseases Paget disease fibrous dysplasia phakomatose...
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Vickers ligament

Vickers ligament is a ligamentous structure connecting the lunate bone and TFCC to the distal radius and is seen in the vast majority of patients with Madelung deformity 1. Release of this thickened ligament may help in improving symptoms associated with Madelung deformity 2.
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Vitamin A

Vitamin A (the retinoids) are a group of fat soluble vitamins required for many physiological functions, mainly vision, reproduction and epithelial maintenance. In the retina, a specific retinoid 11-cis-retinal is formed by photo-isomerisation within the rods and cones. Related pathology Patho...
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Vitamin C

Vitamin C (ascorbic acid) is a water soluble vitamin that is a coenzyme for the formation of the structure protein collagen, particularly creating cross-linking of collagen fibres which greatly increases its tensile strength. It also acts as an antioxidant. Related pathology Pathological manif...
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Vitamin D

Vitamin D is used to describe a group of five fat-soluble secosteroid vitamins required for the homeostasis of serum calcium and phosphorus. Vitamin D is a prohormone that exists in two forms in humans (D2 and D3). Cholecalciferol (D3) acts by regulating calcium and phosphorus intestinal absorp...
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Volar intercalated segmental instability

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

Wackenheims line (also known as the clivus canal line or basilar line) is formed by drawing a line along the clivus and extending it inferiorly to the upper cervical canal. Normally the tip of the dens is ventral and tangential to this line. In basilar invagination odontoid process transects th...
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Wagstaffe-Le Forte fracture

A Wagstaffe-Le Forte fracture refers to an avulsion fracture of the medial aspect of the distal fibula due to avulsion of the anterior tibiofibular ligament attachment. See also lower extremity fractures
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Waldenström sign (hip)

Waldenström sign is the increased distance between the pelvic tear drop and the femoral head. It is a non-specific sign of hip joint effusion. Radiographic features Radiograph >11 mm total distance or >2 mm difference compared to contralateral hip 1, 2 measured between the lateral aspect of ...
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Ward triangle

Ward triangle refers to a radiolucent area between principle compressive, secondary compressive and primary tensile trabeculae in the neck of femur. It should be differentiated from Babcock triangle. History and etymology Named for F O Ward after his original description of the region in 1838.
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Wartenberg syndrome

Wartenberg syndrome also known as cheiralgia paresthetica is due to compression of superficial branch of the radial nerve in the distal forearm. It can be secondary to tight watch band or handcuffs, compression from distal radius fracture or idiopathic.  Clinical presentation Patients present ...
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Wasp-waist sign (spine)

The wasp-waist sign is a radiographic appearance seen in patients with Klippel Feil syndrome. It results from fusion of the vertebral bodies such that the anteroposterior diameter at the level of the affected discovertebral joint is smaller than the diameter at the superior and inferior limits o...
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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. It has a role in determining treatment.  Classification type A below the level of...
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Wedge fracture

Wedge fractures are hyperflexion injuries to the vertebral body resulting from axial loading. Most commonly affecting the anterior aspect, wedge fractures are considered a single-column (i.e. stable) fracture.  Less commonly wedge fractures refer to a subtype of tibial plateau fractures. This a...
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Weightbearing foot series (an approach)

Reporting a weightbearing foot series can be a daunting process if you are inexperienced and often results in the films being left for somebody else to report. This article attempts to demystify the whole process by providing a structured approach to their reporting. Technique The weightbearin...
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Weiss classification of lateral humeral condyle fractures

The Weiss classification is one of the classification systems used for lateral humeral condyle fractures and is based on the degree of displacement measured on an internal oblique view of the elbow: type 1: <2 mm displacement type 2: 2-4 mm displacement type 3: >4 mm displacement The degree ...
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Werner syndrome

Werner syndrome is a progeroid rare autosomal recessive condition attributed to chromosome 8. It should not to be confused with similarly sounding Wermer syndrome. Pathology Werner syndrome is characterised by premature senescence cataracts short stature scleroderma-like skin changes such ...
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Wiberg classification of patella shape

Wiberg classification is a system used to describe the shape of the patella based mainly on the asymmetry between the patellar medial and lateral facets on axial views of the patella. Increasing number type indicates a larger degree of asymmetry. Classification Wiberg type 1 or a roughly symm...
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Widened intercondylar notch

A widened intercondylar notch on knee radiographs is a sign associated with: haemophilic arthropathy (most commonly bilateral) juvenile rheumatoid arthritis (most commonly bilateral) tuberculosis arthropathy (usually unilateral) (3)
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Widening of diploic space

Widening of diploic space refers to expansion of the spongy or cancellous bone between the inner and outer tables of the calavarium. The diploic space is the medullary cavity of the skull, and a location of normal physiologic hematopoiesis in adults. Thus, expansion of this structure most common...
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Widening of interpedicular distance

The interpedicular (IP) distance which is the distance measured between the pedicles on frontal / coronal imaging can be widened in a number of situations. Pathology Causes include diastematomyelia syringomyelia conditions that can cause dural ectasia (can potentially cause widening) Marfa...
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Wilson disease

Wilson disease, also known as hepatolenticular degeneration, is a rare autosomal recessive disorder of copper metabolism affecting multiple systems.  Epidemiology Wilson disease is commonly found in Japan. It affects 1 in 30,000-40,000 individuals 12. Clinical presentation Clinical presentat...
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Wilson disease (musculoskeletal manifestations)

Wilson disease, also known as hepatolenticular degeneration, is a multisystem disease, which rarely has musculoskeletal manifestations secondary to the accumulation of copper in the articular cartilage.  Radiographic features Plain radiographs Reported manifestations include 1-3 premature os...
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Wimberger ring sign

Wimberger ring sign refers to a circular calcification surrounding the osteoporotic epiphyseal center of ossification in scurvy, which may result from bleeding. It must not be confused with Wimberger sign, pathognomonic of congenital syphilis.
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Wimberger sign

The Wimberger sign, also called Wimberger corner sign, refers to localised bilateral metaphyseal destruction of the medial proximal tibias. It is a pathognomonic sign for congenital syphilis. It must not be confused with Wimberger ring sign seen in scurvy, which is sometimes also referred to as...
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Windswept pelvis

Wind-swept pelvis fracture is a combination a unilateral AP compression (open book) injury with a contralateral lateral compression injury.  It occurs when the internal rotation of one iliac wing causes a unilateral sacral compression fracture, while the same forces cause external rotation of t...
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Winking owl sign (spine)

The (absent) pedicle sign, also called the winking owl sign, occurs on plain film when a pedicle is absent. The term, winking owl sign, where the missing pedicle corresponds to the closed eye, the contralateral pedicle to the other open eye, and the spinous process to the beak of the animal on ...
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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 ...
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Wormian bones

Wormian bones (a.k.a. intrasutural bones) is the name given to the additional small bones sometimes found between the cranial sutures of the bones of the skull vault, most commonly in relation to the lambdoid suture. Some reserve the term Wormian bones to just the intrasutural bones proximate to...
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Wormian bones (mnemonic)

A mnemonic to remember ten of the numerous conditions associated with Wormian bones is: PORKCHOPS Mnemonic P - pyknodysostosis O - osteogenesis imperfecta R - rickets K - kinky hair syndrome C - cleidocranial dysostosis H - hypothyroidism/hypophosphatasia O - otopalatodigital syndrome ...
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Wrisberg rip

Wrisberg rips are longitudinal vertical meniscal tears. They occur at the at the junction of the ligament of Wrisberg and the posterior horn of the lateral meniscus, and are commonly associated with anterior cruciate ligament tears 1. 
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Wrist (carpal tunnel view)

The carpal tunnel view is an axial projection to demonstrate the medial and lateral prominences and the concavity. It can be utilised to investigate potential hook of hamate, pisiform and trapezium factures. Patient position patient stands with the back facing the table palmar surface of hand...
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Wrist (clenched fist view)

The clenched fist view is an additional projection used to evaluate suspected widening of the scapholunate interval, often performed bilaterally it is a functional view that requires the patient to clench both hands.  Patient position patient is seated in front of the table  both hands are pl...
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Wrist (horizontal beam lateral view)

The horizontal beam lateral wrist view is a modified lateral projection when performing the three view series of the wrist and carpal bones in trauma. It is the orthogonal projection of the PA wrist without any patient movement, making it the most appropriate projection for patients in pain. Pa...
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Wrist (lateral view)

The lateral wrist view is part of a three view series of the wrist and carpal bones. It is the orthogonal projection of the PA wrist. Patient position patient is seated alongside the table the affected arm if possible is flexed at 90° so the arm and wrist can rest on the table abduct the hum...
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Wrist (oblique view)

The oblique wrist view is part of a three view series of the wrist and carpal bones. It is not generally performed in follow-up studies unless specifically requested. Patient position patient is seated alongside the table the affected arm if possible is flexed at 90° so the arm and wrist can ...
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Wrist (PA view)

The PA wrist view is part of a three view series of the wrist and carpal bones. Although performed PA the view can often be referred to an AP view. Patient position patient is seated alongside the table the affected arm if possible is flexed at 90° so the arm and wrist can rest on the table ...
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Wrist radiograph (an approach)

Wrist radiographs are ubiquitous on any night of the week in emergency departments, especially when pavements are icy! Systematic review Distal radial contour Check the contour of the distal radius: AP the distal radial articular surface should cup the carpals the articular surface should ...
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Wrist radiograph (approach)

Wrist x-rays are commonly used for the assessment of the wrist following trauma. This is usually a fall onto an outstretched hand. Systematic review It is useful to have a systematic approach; I tend to start proximally and work distally looking at structures on both views together: distal ra...
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Wrist radiograph (summary approach)

Wrist radiographs are commonly used for the assessment of the wrist following trauma.  Summary approach alignment AP distal radius and ulna have smooth joint surface carpal arcs are smooth carpal bones do not overlap apart from pisiform and trapezium metacarpals do not overlap and distal...
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Wrist series

The wrist series is comprised of a posteroanterior, oblique, and lateral projection. The series examines the carpal bones that are consisting of the scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate and hamate. It also examines the radiocarpal and distal radiocarpal joint al...
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Xiphoid shape variations

There is considerable anatomic variation in the shape of the xiphoid of the sternum: xiphoid ending is classified as single, double, or triple. xiphoid size varies (e.g. elongated process) xiphoid morphology (e.g. ventral or dorsal deviation, hook-like, reverse S-shape). Clinical presentatio...
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Young and Burgess classification of pelvic ring fractures

The Young and Burgess classification is a modification of the 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. Anteroposterior compress...
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Yunis-Varón syndrome

Yunis Varón syndrome is a rare skeletal dysplasia. It is thought to be autosomal recessive. Radiographic features severe neurologic impairment cleidocranial dysplasia absent clavicles macrocrania diastasis of sutures micrognathia absent thumbs and distal phalanges of fingers hypoplasia ...
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Z deformity

The Z deformity is one of the musculoskeletal manifestation of rheumatoid arthritis in hand: radial deviation at the wrist ulnar deviation of the digits, and often palmar subluxation of the proximal phalanges
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Zebra stripe sign (bones)

The zebra stripe sign occurs where children with osteogenesis imperfecta have been treated with cyclical bisphosphonate therapy, e.g. pamidronate. When the drug is delivered in cycles, dense bone is formed while treatment is being given. This results in dense stripes across the metaphyses of bon...
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Zona orbicularis

The zona orbicularis are circular fibres of the hip joint capsule and form a collar around the femoral neck. Though partly blended with the pubofemoral and ischiofemoral ligaments, these fibres are not directly attached to bone. 
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Z-score

Z-scores are a way to translate individual data points into terms of a standard deviation.  Z = (X - Xbar) / σ X: individual data point Xbar: the arithmetic mean σ: the standard deviation The purpose of the Z-score is to allow comparison between values in different normal distributions. Two...
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Zygoma

The zygoma (or zygomatic bone) is an important facial bone which forms the prominence of the cheek. It is roughly quadrangular in shape. Gross anatomy Zygoma has three surfaces, five borders, and two processes. Surfaces anterolateral surface is convex, pierced at its orbital border by the zy...

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