A cyma line refers to the union of two curved lines in architecture. In a radiological context it refers to the smooth joining of the midtarsal joint lines of the talonavicular and calcaneocuboid joints on both AP and lateral views.
A disruption of the cyma line can indicate true shortening of ...
Cystic adventitial disease (CAD) is an uncommon vascular pathology predominantly affecting peripheral vessels. The vast majority of cases occur in arteries with venous involvement being an even extremely rare occurrence 8.
It typically affects young to middle-aged individuals with...
Cystic angiomatosis is a not so well understood condition which presents with multiple bony cystic lesions in combination with visceral and / or soft tissue cystic lesions. There has been a long standing confusion over the terminology.
A subgroup of patients presenting with this condition prese...
Cysticercosis is a parasitic tissue infection caused by ingestion of tapeworm eggs through a fecal-oral transmission or auto-infection. Humans act as a definitive host in this disease.
CNS manifestations are discussed individually on neurocysticercosis.
The disease is endemic in ...
The musculoskeletal manifestations of cystic fibrosis are uncommon compared to the well known respiratory manifestations.
Symptoms are non-specific and include joint pain, joint swelling, back pain, and myalgia. These may mimic rheumatic symptoms, however, they do not me...
There is broad differential for cyst like lesions around the knee.
The list includes
popliteal synovial cyst - Baker's cyst
intra-articular ganglion cyst
ACL ganglion cyst
PCL ganglion cyst
Hoffa fat pad ganglion cyst
extra-articular ganglion cyst
The dagger sign is a radiographic feature seen in ankylosing spondylitis as a single central radiodense line on frontal radiographs related to ossification of the supraspinous and interspinous ligaments.
Dameron-Lawrence-Bofte classification of proximal fifth metatarsal fractures divides fractures into three zones based on anatomy:
zone 1: tuberosity of 5th metatarsal
avulsion fracture of tuberosity (pseudo-jones fracture)
zone 2: meta-diaphyseal junction
zone 3: proximal dia...
A dedifferentiated chondrosarcoma is a combined tumour made up to two components which are often sharply demarcated from one another (thus raising the possibility of it representing a collision tumour).
conventional chondrosarcoma (low grade)
dedifferentiated high grade areas
Deep bursae are those bursae that are located deep to the fibrous fascia and are normally located between muscles or muscle and bone. These bursae form in utero alongside synovial joint formation 1.
In contrast, superfical bursae are located superficial to the fibrous fascia.
The deep inguinal nodes lie medially to the femoral vein. There are around three in number and receive lymphatic channels that run with the deep femoral vessels and from the glans penis / clitoris from the perineum. There are common channels with the superficial inguinal nodes, and they drain in...
The deep peroneal (fibular) nerve is one of two terminal branches of the common peroneal nerve.
origin: the terminal branch of common peroneal nerve in the lateral compartment of the leg
course: passes into the anterior compartment of the leg, where it courses inferiorly into the dors...
The deep posterior compartment of the leg is one of the four compartments in the leg between the knee and foot. Muscles within this compartment primarily produce ankle plantarflexion and toe flexion, with exception of the popliteus which acts on the knee. Of the two posterior compartments, the d...
The term deep vein thrombosis (DVT) is practically a synonym for those that occur in the lower limbs. However, it can also be used for those that occur in the upper limbs and neck veins. Other types of venous thrombosis, such as intra-abdominal and intracranial, are discussed in specific section...
Degenerative disc disease (DDD) is an exceedingly common entity in the spine, encountered with increasing frequency throughout life and becoming almost universal in late adulthood to a varying degree. It is related to a combination biomechanical stresses and genetic predisposition which alter th...
Degloving injuries can refer to a number of conditions:
degloving soft tissue injury
Morel-Lavallee lesion (closed degloving soft tissue injury)
intramuscular degloving injury
degloving bowel injury
Degloving soft tissue injuries can be extensive and quite severe conditions. These may be open or, less commonly, closed injuries, which are known as Morel-Lavallee lesions. This article focuses on open injuries with closed injuries discussed in the Morel-Lavallee lesion article.
Dehiscence is a general term referring to 'splitting open' and is used in a variety of contexts in medicine generally and radiology more specifically.
The two most common usages are:
splitting open of a wound (e.g. sternal dehiscence)
loss of bone separating one structure from another (e.g. ...
A generalised retardation in skeletal maturation has different causative or aetiological factors, these can be classified as follows:
chronic ill health
congenital heart disease (especially cyanotic)
chronic renal disease
inflammatory bowel disease
malnutrition: failure to thrive (FTT)
Delayed onset muscle soreness (DOMS) refers to the muscular pain and swelling that follows unaccustomed exertion.
Patients may have an ache in affected muscles with reduced strength 4.
DOMS is thought to occur from reversible microstructural muscle injury that...
Deltoid ligament injuries involve the deltoid ligament that forms the medial part of the ankle joint. It attaches the medial malleolus to multiple tarsal bones.
Mechanism of injury
It occurs due to eversion and/or pronation injury, or can be associated with lateral ankle fractures.
The deltoid ligament or medial collateral ligament of the ankle forms the medial part of the ankle joint. It attaches the medial malleolus to multiple tarsal bones.
The ligament is composed of two layers. The superficial layer has variable attachments and crosses two joints whil...
The deltoid muscle is the largest of the shoulder muscles. The muscle is composed of three heads (clavicular, acromial and spinous), although electromyography suggests that there are at least seven control regions that could act independently 1.
origin: lateral 1/3 of the clavicle, acr...
Denervation changes in muscles can be observed in a number of settings.
in the very early stage, muscle signal may be normal
earliest change is increased T2 signal (best seen on a fat saturated T2WI such as STIR)
chronic changes are marked by muscle atrophy and fat...
The differential diagnosis for a dense base of the skull includes:
Van Buchem disease
The differential diagnosis of dense metaphyseal bands is wide.
chronic anaemia, e.g. sickle cell disease, thalassemia
chemotherapy, e.g. methotrexate
growth acceleration lines following growth arrest due to systemic illness or stress in infancy or childhood, e....
Depressed skull fractures result in the bone of the skull vault being folded (depressed) inward into the cerebral parenchyma. It is usually the result of a high energy impact to the skull.
These mostly (~75%) occur in the frontoparietal region 3.
There are number of as...
De Quervain tenosynovitis, also known as washerwoman's sprain/strain, is a painful stenosing tenosynovitis involving the first extensor (dorsal) tendon compartment of the wrist (typically at the radial styloid). This compartment contains the abductor pollicis longus (APL) and extensor pollicis b...
Dercum disease, also known as adiposis dolorosa, is a rare disorder of subcutaneous tissue characterised by multiple painful lipomas.
Although the exact incidence is unclear, Dercum disease affects women more than men 1,2. It is usually sporadic, however, autosomal dominant forms ...
Dermatofibrosarcoma protuberans (DFSP) is an uncommon exophytic, slow growing, low grade, spindle cell tumour arising in the dermal and subcutaneous tissues, particularly of the trunk region with excellent outcome after complete surgical resection.
The tumour occurs in patients of...
Dermatographia, also known as skin writing, refers to a skin condition in which skin scratches causes linear red marks. The cause is unknown, however, it is related to penicillin use and mastocytosis.
Dermatomyositis is an autoimmune inflammatory myositis.
There is a recognised female predilection. It has a bimodal age of presentation depending on the variant:
juvenile dermatomyositis (JDM): affects children and tends to be more severe
adult dermatomyositis (ADM): typically a...
A derotational screw is an orthopaedic device used for internal fixation of fractures to, unsurprisingly, limit rotation of the fracture.
They are applied across fractures at risk of rotation and hence avascular necrosis.
Describing a fracture is a basic requirement when making an assessment of a plain radiograph. There are many ways to approach the assessment of the radiograph; this is just one approach.
I: Describe the film
What film (or films) are you looking at? Check the who, what, why, when, and where.
Desmoid tumours are benign, non-inflammatory fibroblastic tumours (see WHO 2002 classification of soft tissue tumours) with a tendency for local invasion and recurrence but without metastasis.
The terms desmoid tumour and aggressive fibromatosis are occasionally used synonymously b...
Desmoplastic fibromas are extremely rare bone tumours that do not metastasise but may be locally aggressive. They are considered to be a bony counterpart of soft tissue desmoid tumours and are histologically identical.
Incidence is ~0.3%. The most common areas of involve...
Developmental dysplasia of the hip (DDH) denotes aberrant development of the hip joint and results from an abnormal relationship of the femoral head to the acetabulum. There is a clear female predominance, and it usually occurs from ligamentous laxity and abnormal position in utero. Therefore, i...
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.
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...
A die-punch fracture results from axial loading forces on the distal radius. It is an intra-articular fracture of the lunate fossa of the distal radius1. 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 some 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 ...
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...
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%, 90 degrees) of the circumference of an intervertebral disc 3. Because it is limited by the annulus fibrosus it does not ext...
Disc desiccation is an extremely common degenerative change of intervertebral discs. The incidence climbs with age, and to a large degree a gradual desiccation is a 'normal' part of disc aging. It results from replacement of the hydrophilic glycosaminoglycans within the nucleus polposus with fib...
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/osteop...
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...
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.
Most ankle injuries occur because of an inversion injury. A pure...
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...
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 angulation, this is termed a Colles fracture.
This is a summar...
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 defect of the patella is a benign subchondral lesion 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.