The distal intersection syndrome relates to tenosynovitis of the extensor pollicis longus (EPL) tendon, where it crosses the extensor carpi radialis longus (ECRL) and brevis (ECRB) tendons 1. It is distinct from intersection syndrome which occurs more proximally in the forearm at the intersectio...
Distal phalanx fractures are the most common fractures in the hand.
They represent >50% of all phalangeal fractures and frequently involve the ungual tuft 1.
They are frequently related to sports, with lesions such as the Mallet finger and the Jersey finger, or can occur after a crush injury,...
Distal radial fractures are a heterogeneous group of fractures that occur at the distal radius and are the dominant fracture type at the wrist. These common fractures usually occur when significant force is applied to the distal radial metaphysis.
Distal radial fractures can be s...
This is a basic article for medical students and other non-radiologists
Distal radial fractures are a relatively common group of injuries that usually occur following a fall. The commonest of these fractures is a transverse extra-articular fracture and where there is associated dorsal angulatio...
The distal radioulnar joint is a pivot type synovial joint between the distal radius and ulna.
articulation: pivot type synovial joint between the distal aspect of the radius and the ulna
movement: rotation of the distal radius
ligaments: triangular ligament, and anterior and posteri...
Isolated distal radioulnar joint (DRUJ) dislocations are rare and are more commonly part of complex forearm fracture-dislocations.
Wrist pain, swelling and deformity following FOOSH or direct trauma. The patient will be unable to supinate/pronate the forearm 1,2.
The tibiofibular syndesmosis is a complex fibrous joint composed of multiple ligaments and a broad fibrous membrane (the interosseous membrane) that spans between the tibia and fibula throughout the length of both bones.
The distal osseous part of this syndesmotic joint includes the following f...
Distal ulnar fractures are common, and usually occur with a concurrent distal radius fracture.
Isolated fractures occurs as a result of direct force to the ulna. Fractures associated with radius fractures usually occur as the result of a fall on an outstretched arm.
Distal ulnar fra...
Dorsal defects of the patella are benign subchondral lesions of unknown aetiology and a normal developmental anomaly of the patella, which can be mistaken for a pathological process such as a focus of infection or osteochondritis dissecans.
Dorsal defect of patella occurs in males...
Dorsal epidural disc migration represents, as the name suggests, migration of disc material, usually a sequestrated disc fragment, into the dorsal (posterior) epidural space, posterior to the theca. This is a rare occurrence, often not suspected preoperatively and is almost invariably encountere...
Dorsal intercalated segment instability (DISI) is one of the types of instability involving the wrist. It occurs because of a disruption of the dorsal intercarpal ligament. It is more often encountered than volar intercalated segment instability (VISI).
wrist trauma, with ...
The four dorsal interossei muscles are the most superior muscles in the sole of the foot and abduct the second to fourth toes relative to the long axis through the second toe.
sides of metatarsals of toes I to V
extensor hoods and bases of proximal phalanges of toes...
The interossei muscles as a group consist of four palmar (1st is often rudimentary) and four dorsal muscles. Collectively, the interossei contribute to abduction and adduction of the fingers and also contribute to flexion of the metacarpophalangeal joints (MCPJ) and extension of the interphalan...
The dorsal scapular nerve is a branch from the C5 root of the brachial plexus and supplies the rhomboid muscles.
Posterior aspect of the C5 root of the brachial plexus.
It courses through scalenus medius then accompanies the dorsal scapular vessels inferiorly, de...
Dot in a circle sign is an MRI sign for maduromycosis or mycetoma.
It is described as a classic appearance on T2 weighted images which show a small rounded hyperintensity (representing granulation tissue), surrounded by a low signal intensity rim (representing fibrous septa) with a hypointense ...
The double axillary pouch sign is a collection of fluid between a torn anteroinferior glenoid labrum and the glenoid rim, giving the appearance of a second axillary pouch.
The sign is seen best with MR arthrography on the coronal view, and is considered by some, a very specific sign for an ante...
Double contour cartilage line is a sign in ultrasonography of the gout arthropathy which is characterised by an echogenic line on the outer surface of the joint cartilage parallel to the subchondral bone secondary to deposition of monosodium urate crystals on the surface of hyaline articular car...
The double contour sign is a helpful radiologic sign which is seen on true lateral plain radiographs of trochlear dysplasia. A double line at the anterior aspect of condyles that seen if medial condyle is hypoplastic.
crossing sign of trochlear dysplasia
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...
The double density sign, also sometimes clumsily referred to as the hotter spot within hot area sign, is a bone scan sign of an osteoid osteoma.
It refers to a central focus of intense uptake (the nidus) within a surrounding lower, but nonetheless increased uptake, rim.
Thickening of the insertion of the lateral pterygoid muscle can mimic an anterior displaced temporomandibular disc. When both thickening of the inferior belly insertion and an anteriorly displaced disc are present, the two structures parallel each other; the so-called "double disc" sign.
A double-layered patella (DLP) is a rare form of bipartite patella.
It is a congenital anomaly which presents with multiple fragmented patellae with smooth, well-corticated borders. A double-layered patella is considered pathognomonic for multiple epiphyseal dysplasia.1
The double line sign is an MRI finding seen at the periphery of a region of osteonecrosis (avascular necrosis, bone infarct). It is best seen on T2 weighted sequences and consists of an inner bright T2 line representing granulation tissue and surrounding dark zones representing adjacent scleroti...
The double Oreo cookie sign refers to the presence of two hyperintense lines in the superior glenoid labrum, one of which represents a superior labral tear and the other a physiological sublabral recess 1, 2.
This pattern is likened to an Oreo cookie with two layers of (white) cream and three l...
The double PCL sign appears on sagittal MRI images of the knee when a bucket-handle meniscal tear (medial meniscus in 80% of cases) flips towards the centre of the joint so that it comes to lie anteroinferior to the posterior cruciate ligament (PCL) mimicking a second smaller PCL.
A double PCL ...
The doughnut sign refers to the bone scan pattern whereby there is increased uptake peripherally with a photopenic centre. This appearance may be seen in a number of cystic lesions including:
aneurysmal bone cyst
giant cell tumour
simple bone cyst
The doughnut sign is a non-specific sign, an...
Dracunculiasis (also known as guinea worm disease) is a potentially disabling infection caused by Dracunculus medinensis (meaning "little worm from Medina").
The radiologic finding of a calcified guinea worm is common in endemic areas.
In the vast majority of cases (one...
Dripping candle wax sign, also known as flowing candle wax appearance, describes the appearance of sclerotic cortical thickening in melorheostosis. The irregular cortical hyperostosis typically occurs on one side of the involved bone and undulates along much like melted wax down a candle.
Dual-energy x-ray absorptiometry (DEXA) is a technique used to aid in the diagnosis of osteopenia and osteoporosis.
Values are calculated for the lumbar vertebrae and femur preferentially, and if one of those sites is not suitable (e.g. artifact, patient mobility, histor...
Duchenne muscular dystrophy (DMD) is a dystrophinopathy and the most common muscular dystrophy.
DMD has an incidence of 1 in 3500 to 5000 males 1,2. The condition is extremely rare in females due to its inheritance pattern, as discussed below 1.
The dumbbell appearance of spinal tumours refers to a tumour which has both a component within the canal and a component in the paravertebral space contiguous with each other via a thinner tumour component traversing the neural exit foramen.
The appearance can be seen in:
spinal nerve sheath t...
A Dupuytren contracture, or palmar fibromatosis, is a fibrosing condition that characteristically presents as a firm nodularity on the palmar surface of the hand with coalescing cords of soft tissue on the webs and digits.
It is considered the most common of the superficial fibrom...
Duverney fractures are a type of pelvic fracture most commonly occurring in the setting of a direct blow to the ilium, with a resultant isolated iliac wing fracture. It is regarded as a stable injury but may be operated on in the event of severe comminution.
History and etymology
It is named ...
Dynamic hip screws (DHS) are a femoral head-sparing orthopaedic device used to treat femoral neck fractures. It is sometimes referred to as a pin and plate.
Neck fractures that are undisplaced and hence have a low risk of avascular necrosis (Garden I and II fractures) can be treated with head-p...
Dysplasia epiphysealis hemimelica (DEH), also known as Trevor disease, is an extremely rare, non-hereditary disease that is characterised by osteochondromas arising from the epiphyses.
The incidence is estimated at ~1:1,000,000 3. There is a recognised male predilection (M:F = 3:1...
Dystrophic soft tissue calcification is a broad term that encompasses a wide range of pathologies that cause soft-tissue calcification and is caused by calcification of damaged tissues. The amorphous calcification that results may be small or large. In some cases, ossification may occur - this...
This classification was proposed by Eaton and Malerich in 1980, and presently (time of writing, August 2016) along with Keifhaber-Stern classification, is the most widely accepted classification of volar plate avulsion injuries 1.
Knowledge of the orthopaedic Eaton classification is practical ...
Ectodermal dysplasia (ED) refers to a heterogeneous group of genetic disorders that cause abnormal ectoderm development. The effect is a non-progressive defect in the development of two or more tissues derived from embryonic ectoderm.
ED is rare with an estimated prevalence of 1:...
Ectrodactyly (also known as a split hand-split foot malformation, cleft hand or lobster claw hand) is a skeletal anomaly predominantly affecting the hands (although the feet can also be affected). The condition has a highly variable severity.
The estimated incidence is at ~ 1 in 9...
The wrist series is comprised of a posteroanterior, oblique, and lateral projection. The series examines the carpal bones (namely, the scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate and hamate). It also examines the radiocarpal joint along with the distal radius and ulna....
Ehlers-Danlos syndrome comprises a heterogeneous group of collagen disorders (hereditary connective tissue disease).
There is a recognised male predominance.
Clinically manifests by skin hyperelasticity and fragility, joint hypermobility and blood vessel fr...
Elastofibroma dorsi is a benign soft-tissue tumour with a characteristic location and imaging appearance.
It is more frequently seen in older women, with a reported female predilection of 5-13:1. The estimated mean age at diagnosis around 65-70 years.
The elbow is a complex synovial joint formed by the articulations of the humerus, the radius and the ulna.
The elbow joint is made up of three articulations 2,3:
radiohumeral: capitellum of the humerus with the radial head
ulnohumeral: trochlea of the humerus wi...
The elbow AP view is part of the two view elbow series, examining the distal humerus, proximal radius and ulna.
The projection demonstrates the elbow joint in its natural anatomical position allowing for adequate radiographic examination of the articulations of the elbow including the radiohum...
Elbow arthroplasties are an increasingly common joint replacement, most often used for treatment of late stage rheumatoid arthritis, but which may also be used as a treatment for late stage osteoarthritis or complex fractures of the proximal radius, proximal ulna, or distal humerus.
The elbow bursae are a collection of synovial-lined bursae that exist around the elbow. They can be divided into bursae around the olecranon and in the cubital fossa.
superficial olecranon bursa: lies between the olecranon and the subcutaneous tissue.
subtendinous olecranon ...
Elbow dislocation is the second most common large joint dislocation in the adult population.
A dislocation with no fracture is simple whereas an accompanying fracture makes the dislocation complex. The most common fracture is a radial head fracture, although coronoid process fracture is also c...
The elbow extension test is a clinical decision rule aimed at reducing the number of unnecessary elbow radiographs in patients aged ≥3 years.
The test has a specific examination whereby the seated patient, with the arm in supination and 90º shoulder flexion, is asked to fully extend the elbow ...
An elbow joint effusion is a key finding to recognise on an elbow radiograph and should be used as a trigger to search for a fracture.
Finding an effusion
Recognising an elbow joint effusion on lateral radiographs is an essential radiology skill. While the fluid itself is not discretely seen...
The lateral elbow view is part of the two view elbow series, examining the distal humerus, proximal radius and ulna. It is deceptively one of the more technically demanding projections in radiography 1-3.
The projection is the orthogonal view of the AP elbow allowing for examination of the ulna...
Elbow ossification occurs at the six elbow ossification centers in a reproducible order. Being familiar with the order of ossification of the elbow is important in not mistaking an epicodylar fracture for a normal ossification center.
The order of appearances of the elbow os...
Mnemonics for elbow ossification include CRITOE and CRITOL. These are essentially the same, apart from the terminal letter which represents the External or Lateral epicondyle.
C - capitellum
R - radial head
I - internal epicondyle
T - trochlea
O - olecranon
E - external ...
This is a basic article for medical students and other non-radiologists
Elbow radiographs are common plain films that are obtained frequently in the emergency department.
anterior humeral line
drawn down the anterior surface of the humerus
should intersect the mi...
The elbow series is a set of radiographs taken to investigate elbow joint pathology, often in the context of trauma. It usually comprises an AP and lateral projection, although other non-standard, modified projections are utilised for specific indications.
Elbow x-rays are indicate...
This is a basic article for medical students and other non-radiologists
An elbow series is the standard series of radiographs that are performed when looking for evidence of fracture, dislocation or elbow joint effusion following trauma.
This is a summary article. For more i...
Elbow synovial fold syndrome refers to a condition where patients experience a cluster of symptoms due to the presence of synovial folds (also known as synovial fringe or plicae).
It tends to be more common in athletic young adults. It is associated with certain sporting activitie...
Elephantiasis nostras verrucosa is a rare cause of chronic lymphoedema, arising in the setting of chronic nonfilarial lymphedema caused by bacterial or noninfectious obstruction of the lymphatics.
It presents mostly as grossly oedematous and disfigured lower extremities, ...
The atypical 11th rib is one of two floating ribs.
The 11th rib has a single facet on its head for articulation with the T11 vertebra. It has a short neck and no tubercle. The angle is slight. Its costal groove is shallow. The internal surface of this rib faces slightl...
The embryonal subtype of rhabdomyosarcoma is the most common variety of rhabdomyosarcoma, accounting for 50-70% of cases 1-2. It is typically seen in children below the age of 15.
Embryonal rhabdomyosarcomas are further divided into three sub types 1:
spindle cell rhabdomyosarcoma
Emphysematous osteomyelitis is an extremly rare form of osteomyelitis which is complicated by infection with gas forming organims. Only a handful of cases are published in literature.
Commonely reported organisms include 1
Empyemas are purulent inflammatory collections within a body cavity. They are similar to abscesses, which arise within parenchymal tissue rather than occupying a pre-existing anatomical space.
Colloquially, the term empyema is used to refer to thoracic empyemas but there are variou...
Enchondromas (or chondromas 7) are a relatively common benign medullary cartilaginous neoplasm with benign imaging features. They account for the E in the popular mnemonic for bubbly bone lesions FEGNOMASHIC. They are sometimes classified under the umbrella term low grade chondral series tumours...
Enchondromatosis or Ollier disease is a non-hereditary, sporadic, skeletal disorder characterised by multiple enchondromas principally located in the metaphyseal regions.
Some authors make a distinction between Ollier disease and enchondromatosis on the basis of distribution. In th...
Distinguishing between enchondromas and low-grade conventional chondrosarcomas is a frequent difficulty as the lesions are both histologically and radiographically very similar.
It is important to remember, though, that differentiating between them may be a moot point since both can either be c...
Endochondral ossification describes the process of ossification from mesenchymal cells (stem cells) with a cartilaginous template and is involved in the healing process of fractures.
Bone formation occurs at centers of ossification (or ossification centres) which are either primary or secondary...
Endosteal scalloping refers to the focal resorption of the inner layer of the cortex (i.e. the endosteum) of bones, most typically long bones, due to slow-growing medullary lesions.
It is important to note that although it is evidence of a slow non-infiltrative lesion, it does not equate to ben...
Enlocated is a term popular among Australasian (Australia and New Zealand) radiologists and orthopaedic surgeons to describe a joint that is not dislocated.
It does not appear in the Oxford dictionary, nor is it widely used elsewhere in English-speaking countries. Most authors prefer the terms...
The Enneking surgical staging system (also known as the MSTS system) is based on tumour grade, local spread and metastatic disease of malignant musculoskeletal tumours.
It does not classify skull tumours or marrow-originating tumours (e.g. lymphoma, plasmacytoma / multiple myeloma, Ewing sarcom...
An enostosis (pl. enostoses, also known as a "bone island") is a common benign bone lesion, usually seen as an incidental finding. They constitute a small focus of compact bone within cancellous bone. Enostoses can be seen on radiographs, CT, and MRI, and are considered one of the skeletal “don’...
Enteropathic arthritis (EA) is a form of chronic, inflammatory arthritis associated with the occurrence of an inflammatory bowel disease (IBD), and is classified as a form of seronegative spondyloarthropathy.
Approximately 20% of people with Crohn disease or ulcerative colitis may...
An enthesis (pl. entheses) is the connective tissue junction where ligaments and tendons attach to bone.
There are two types of entheses:
The ligament or tendon attaches directly to the bone.
Enthesitis refers to inflammation of the enthesis (the attachment of ligament or tendon to bone).
Enthesitis may be the result of repetitive mechanical stress or a more generalised inflammatory condition. Enthesitis is associated with the HLA-B27 inflammatory arthritides such as ankylosing spo...
Enthesopathy is a broad term that includes any disorder that occurs where tendons or ligaments attach to bone (the enthesis).
The causes of enthesopathy are broad. It may be localised and secondary to repetitive mechanical strain, or secondary to another condition which may be confined to a sin...
Eosinophilic fasciitis (EF), also known as Shulman syndrome, is an uncommon connective tissue disorder.
It can potentially present at age. There is a recognized female predilection 3,4.
Patients typically present with pronounced extremity oedema and skin in...
Epibasal fractures of the thumb (also called pseudo-Bennett fracture) are two-piece fractures of the proximal first metacarpal bone. They are usually stable, depending on the degree of displacement, and often do not require surgery. It is important to distinguish them from intra-articular fractu...
Epicondyle fractures are common injuries in children. They represent 10% of all elbow fractures in children and usually occur in boys after a fall on an outstretched arm.
Medial epicondyle fractures comprise most of these injuries. They can usually be treated with splinting and early physiother...
Epidermal inclusion cysts are common cutaneous lesions that represent proliferation of squamous epithelium within a confined space in the dermis or subdermis.
Synonyms include "epidermoid cyst" and "epidermoid inclusion cyst". These are occasionally termed "sebaceous cyst", althoug...
Epidermolysis bullosa refers to a rare group of genetically determined conditions characterised by blistering of the skin. This can be limited to the soles and palms or extensive whole body involvement.
limited to the mucosa of the gastr...
Epidural blood patch is a treatment option for patients with craniospinal hypotension or post lumbar puncture headaches. The procedure can be done blind or under fluoroscopic or CT guidance, and is performed predominantly by radiologists and anaesthetists.
Epidural lipomatosis refers to an excessive accumulation of fat within the spinal epidural space resulting in compression of the thecal sac. In severe cases, compression may be symptomatic. The lumbar region is most frequently affected.
The demographics of affected individuals ref...
An epiphyseal bracket represents an abnormal development of physeal tissue along the diaphysis which occurs in the hand and the feet 1.
An epiphyseal equivalent refers to bones that are considered similar to the epiphyses and therefore have a similar list of diseases that cause pathology.
Epiphyseal lesions comprise of tumours and other pathologies that occur around the epiphysis and any epiphyseal equivalent bone.
Common differential diagnoses include 2-4:
chondroblastoma: rare epiphyseal tumour found in young adults; it does not usually extend into the...
The differential diagnosis of epiphyseal overgrowth includes:
juvenile rheumatoid arthritis
Legg-Perthes disease (healed )
dysplasia epiphysealis hemimelica
fibrous dysplasia of epiphysis
pyogenic arthritis (chronic)
Epiphyseal spur refers to a spur seen in skeletally mature individuals arising at the level of closed epiphyseal line. It may be seen in any epiphysis.
The epiphyses (singular: epiphysis) are the rounded portions at the ends of a bone separated from the metaphysis by the physis. The epiphysis contributes to a joint, compared with an apophysis which is a site of tendon or ligament attachment. Once the growth plate has fused, the epiphysis and me...
Episternal (or suprasternal) ossicles are accessory bones and a normal variant of the sternum. They result from supernumerary ossification centers and are seen in ~4% (range 1-7%) of the population.
Episternal ossicles are usually located posterior or superior to the superior bor...
There are numerous eponymous fractures which are named after the people who first described their existence 1:
Bankart fracture: glenoid
Barton fracture: wrist
Bennett fracture: thumb
Bosworth fracture: ankle
Chance fracture: vertebral
Charcot joint: foot
Chopart fracture: foot
Erdheim-Chester disease (ECD) is a rare non-Langerhans cell, non-familial multisystemic granulomatosis, with widespread manifestations and of highly variable severity. The most common presenting symptom is bone pain.
Erdheim-Chester disease is a rare, non-inherited disease of midd...
The erector spinae group is the intermediate layer of the intrinsic muscles of the back. This group is made of three subgroups, with the group divisions occurring by location. The iliocostalis group occurs most laterally, followed by the longissimus group, and finally the spinalis as the most me...
There are multiple handy mnemonics to recall the erector spinae muscles. They usually describe the position from lateral to medial.
I Like Standing
I Love Sex
I Long for Spinach
I Like Siri
Erlenmeyer flask deformity (EFD) (also known as metaphyseal flaring) refers to a radiographic appearance typically on a femoral radiograph demonstrating relative constriction of the diaphysis and flaring of the metaphysis.
It has been classically used with reference to the distal ends of the fe...
Some of the causes of an Erlenmeyer flask deformity can be recalled with the following mnemonics:
C: craniometaphyseal dysplasias
sickle cell disease
N: Niemann-Pick disease
G: Gaucher dis...