Developmental stages of the spheno-occipital synchondrosis take place in a number of predictable steps.
Fusion of the spheno-occipital synchondrosis was well underway by the age of 15 years and is complete by 17-18 years.
Fusion begins superiorly and progresses inferiorly.
Persistence of a ...
Diabetic myonecrosis is an uncommon complication of diabetes mellitus, occurring in patients with chronic poor glycemic control.
There is a slight predilection for females and patients with type 1 diabetes. The average age of presentation is 40 years.
Diaphragmatic eventration refers to an abnormal contour of the diaphragmatic dome. It typically affects only a segment of the hemidiaphragm, compared to paralysis/weakness where the entire hemidiaphragm is typically affected.
Diaphragmatic eventration is congenital in nature and due...
Diaphragmatic paralysis can be unilateral or bilateral.
Clinical features are highly variable according to underlying aetiological factor:
unilateral paralysis: asymptomatic in most of the patients as the other lung compensates
may have dyspnoea, headaches, fatigue, ins...
Diaphyseal lesions are unsurprisingly predominantly found centred in the diaphysis.
simple bone cyst
myeloma / plasmacytoma
round cell tumour, e.g. Ewing sarcoma (children)
A mnemonic for a short list of diaphyseal lesions is:
C: bone cysts
E: enchondroma/Ewing sarcoma
M: bone metastasis
E: eosinophilic granuloma
N: non-ossifying fibroma (NOF)
The diaphyses (singular: diaphysis), sometimes colloquially called the shafts, are the main portions of a long bone (a bone that is longer than it is wide) and provide most of their length.
The diaphysis has a tubular composition with a hard outer section of hard cortical bone and a central po...
Diarthroses are a functional class of joint that are freely mobile. All synovial joints are considered diathroses.
Diastasis recti (rectus diastasis) is a stretching of the linea alba with abnormal widening of the gap between the two sides of the rectus abdominus muscle (inter-recti distance).
The degree of widening needed for the diagnosis is controversial, with the degree of abdominal protrusion (rather t...
Diastrophic dysplasia (DTD) is a type of short limb skeletal dysplasia (micromelic dwarfism). Adult patients have a stature between 100 and 140 cm.
There may be a relatively increased prevalence in Finland ref.
Typically there is limb shortening, hitchhiker thu...
Die-punch fractures result from an axial loading force on the distal radius. It is an intra-articular fracture of the lunate fossa of the distal radius 1. It is by definition depressed or impacted and is named after the machining technique of shearing a shape, depression or hole in a material wi...
Dietrich disease is the eponymous name given to osteonecrosis involving a metacarpal head 1.
The condition is rare and most often spontaneous but may be associated with trauma, systemic lupus erythematosus or steroid use. Any metacarpal may be affected however the long metacarpals...
The difference in vertical mid-vertical angle is the difference in the vertical mid-vertebral angle (VMVA) between the caudal segment angle and the adjacent cephalad segment angle of the three most caudal segments of the lumbar spine as measured on a mid-sagittal MRI or a lateral radiograph.
Forefoot pain in the metatarsal region is a common complaint and may be caused by a number of conditions. It is worthwhile for a radiologist to have knowledge of the potential causes and their imaging features 1.
plantar plate disruption
Diffuse bone sclerosis can result from a number of causes. They include:
sickle cell disease
diffuse osteosclerosing myeloma: rare
metabolic bone disorders
Useful mnemonics for remembering causes of diffuse bony sclerosis include:
3 M's PROOF
Regular Sex Makes Occasional Perversions Much More Pleasurable And Fantastic 1
3 M's PROOF
metastases (osteoblastic metastases)
Diffuse idiopathic skeletal hyperostosis (DISH), also referred to as Forestier disease, is a common condition characterised by bony proliferation at sites of tendinous and ligamentous insertion of the spine affecting elderly individuals. On imaging, it is typically characterised by the flowing o...
A diffuse homogeneous bone marrow FDG uptake usually reflects hyperplastic bone marrow which can be seen in the following conditions:
granulocyte colony stimulating factor (G-CSF)
Diffuse T1 vertebral bone marrow signal loss has a number of causes. T1-weighted imaging without fat suppression is one of the most important sequences for distinguishing between normal and abnormal bone marrow. Given the homogeneity, this appearance can often be difficult to spot as abnormal. ...
A dinner fork deformity, also known as a bayonet deformity, occurs as the result of a malunited distal radial fracture, usually a Colles fracture. The distal fragment is dorsally angulated, displaced and often also impacted. The term is descriptive, as the lateral view of the wrist is similar to...
A direct inguinal hernia arises from protrusion of abdominal viscera through a weakness of the posterior wall of the inguinal canal medial to the inferior epigastric vessels, specifically through the Hesselbach's triangle.
This type of hernia is termed direct as the hernial sac directly protrud...
The term disarticulation refers to the disconnection of all or part of a limb from the body, specifically through a joint. This is in contrast to amputation, which is the disconnection or removal of the structure through a bone.
Discal cysts (also known as a disk cyst or disc cyst) are uncommon lesions of the spine, representing an extrathecal cyst which communicates with the adjacent intervertebral disc through an annular fissure.
The vast majority of discal cysts, as rare as they are, have been reporte...
A disc bulge represents displacement of the outer fibres of the annulus fibrosus beyond the margins of the adjacent vertebral bodies, involving more than one-quarter (25% or 90 degrees) of the circumference of an intervertebral disc 3. Because it is limited by the annulus fibrosus it does not e...
Disc desiccation is an extremely common degenerative change of intervertebral discs. The incidence climbs with age, and to a large degree a gradual dehydration is a 'normal' part of disc ageing. It results from replacement of the hydrophilic glycosaminoglycans within the nucleus pulposus with fi...
Disc extrusion is a type of intervertebral disc herniation and is distinguished from a disc protrusion in that it:
in at least one plane, has a broader dome (B) than a neck (A)
extends above or below the disc level (into the suprapedicular or infrapedicular zone)
Disc extrusions are a...
Disc herniation refers to the displacement of intervertebral disc material beyond the normal confines of the disc but involving less than 25% of the circumference (to distinguish it from a disc bulge). A herniation may contain nucleus pulposus, vertebral endplate cartilage, apophyseal bone/osteo...
Discogenic vertebral sclerosis is one of the skeletal "do not touch" lesions and should not be confused with a metastatic lesion or disc space infection. It can lead to an unnecessary biopsy.
The typical clinical presentation is a middle-aged female with chronic low back ...
Discoid menisci are those that have a body that is too wide, usually affecting the lateral meniscus. They are incidentally found in 3-5% of knee MRI examinations.
Discoid menisci condition is congenital, frequently bilateral (up to 50%) and has been reported in twins, although no ...
Disc osteophyte complex is a term used on MRI of the cervical spine to denote the presence of disc protrusion and/or marginal endplate osteophytes resulting in narrowing of the cervical canal. The term was introduced early in the practice of MRI as distinguishing between disc and osteophyte can ...
Disc protrusions are a type of disc herniation characterised by protrusion of disc content beyond the normal confines of the intervertebral disc, over an segment less than 25% of the circumference of the disc. The width of the base is wider than the largest diameter of the disc material which pr...
Sequestrated disc, also referred to as a free disc fragment, corresponds to extruded disc material that has no continuity with the parent disc and is displaced away from the site of extrusion. By definition, it corresponds to a subtype of disc extrusion.
The term "migrated" disc refers only to ...
Disorganised or complex periosteal reaction has spicules with random orientation and appearance. It can be seen in highly aggressive processes:
malignant fibrous histiocytoma
spindle cell sarcoma
The disproportionate posterior horn sign is a feature described with a meniscal tear having a posteriorly flipped fragment.
Bucket handle tears of meniscus of the knee joint constitute 10% of meniscal tears. They consist of a vertical or longitudinal tear (which includes vertical-obl...
Distal appendicular skeletal metastases, especially distal to the knee and elbow joints, are uncommon.
Localised pain and swelling, along with pathological fractures, are the most common 3.
Malignancies that most commonly spread to appendicular ske...
Erosion or absence of the distal ends of the clavicles may be seen in a wide range of conditions.
weightlifter's shoulder: due to repetitive microtrauma; classically described in weightlifters, but can affect anyone performing repetitive overhead lift...
This is a basic article for medical students and other non-radiologists
Distal fibula fractures are the most common type at the ankle and are usually the result of an inversion injury with or without rotation. They are the extension of a lateral collateral ligament injury.
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 among 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. When associted with a crush...
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...
A positive dorsal fat pad or stripe sign is defined as a convex dorsal displacement of the dorsal fat pad of the wrist. A positive sign may indicate a distal radius fracture. Is it best visualised on the lateral view of the wrist.
The normal dorsal skin subcutaneous fat pad is a thin c...
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), or if...
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...
The Eaton 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 pract...
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 is 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 acute flexion AP is a modified elbow AP projection for patients whom cannot straighten their arm for examination. It is comprised of two views demonstrating the distal humerus and proximal forearm structures
Distal humerus projection
patient is seated alongside the ...
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 ...
The Coyle's view of the elbow is an axial projection that is performed in addition to the standard elbow series when there is suspicion of a radial head fracture 1-3. The projection isolates the radial head using a modified radiographic technique.
patient is sitting next to th...
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 fract...
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 ...
The elbow external oblique view is an additional projection of the elbow often used to better demonstrate the radial head free from superposition.
patient is seated alongside the table
the fully extended arm and forearm, in a supinated position, are kept in contact with the t...
The inferior-superior elbow view is a modified elbow projection for patients in acute flexion greater than 90 degrees, it is also an additional projection to better demonstrate the olecranon process.It is comprised of two views demonstrating the distal humerus and proximal forearm structures
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...
The elbow medial oblique view is a specialised projection, utilised to demonstrate both the coronoid process in profile and the olecranon process sitting within the olecranon fossa of the humerus.
the patient is seated alongside the table
fully extended arm and forearm, in a ...