The critical zone of the rotator cuff is an area approximately 8-15 mm from the insertion of the rotator cuff tendons onto the greater tubercle of the humeral head, mainly within the supraspinatus tendon. This is a watershed zone between the anterior and posterior circumflex humeral, thoracoacro...
The crossing sign is seen on true lateral plain radiographs of the knee when the line of the trochlear groove crosses the anterior border of one of the condyle trochlea. It is a predictor of trochlear dysplasia. Trochlear dysplasia has been linked to recurrent patellar dislocation 1,2,4. The cro...
Crouzon syndrome is rare disorder characterised by premature craniosynostoses.
abnormal calvarial shape: in severe case can give a "cloverleaf skull"
shallow orbits with exopthalmos
mid facial hypoplasia
It carries an autosomal dominant ...
The crowned dens syndrome is an inflammatory condition resulting from crystal deposition in cruciform and alar ligaments surrounding the dens, appearing as a radiopaque 'crown' surrounding the top of the dens. It typically presents with pain and increased inflammatory markers.
The cruciate ligament of the atlas (also known as the cruciform ligament) is an important ligamentous complex that holds the posterior dens of C2 in articulation at the median atlantoaxial joint. It lies behind a large synovial bursa (surrounded by loose fibrous capsule) and consists of two band...
Crystal arthropathies are a group of joint disorders due to deposition of crystals in and around joints which lead to joint destruction and soft tissue masses.
The most common arthropathies are:
gouty arthropathy due to monosodium urate (MSU) deposition
pseudogout due to calcium py...
The C sign is an important radiological sign which may be seen on a lateral radiograph of the ankle in those with the talocalcaneal subtype of tarsal coalition.
A continuous C-shaped arc on a lateral ankle radiograph is formed by the medial outline of the talar dome an...
The cubital fossa is a triangular space which forms the transition between the arm and the forearm. It is located anterior to the elbow joint.
superior: the line joining the medial and lateral humeral epicondyles
lateral: medial border of brachioradialis
The cubital tunnel is a space through which the ulnar nerve passes posterior to the medial epicondyle of the humerus.
cubital tunnel retinaculum (a.k.a. ligament or band of Osborne), extends from the olecranon to the medial epicondyle
anconeus epitrochlearis (...
Cubital tunnel syndrome is a type of ulnar nerve compression neuropathy which can occur from a pathological compression of the ulnar nerve at the cubital tunnel.
It is the second most common peripheral neuropathy of the upper extremity 1,3.
Ulnar nerve comp...
Cubitus varus (gunstock deformity) is a malalignment of the distal humerus that results in a change of carrying angle from the physiologic valgus alignment (5-15 degrees) of the arm and forearm to varus malalignment. Historically, it is a complication of supracondylar fractures with a frequency ...
The cuboid bone is one of the tarsal bones located lateral to the lateral cuneiform bone and has an important articulation with the calcaneus.
The cuboid is a wedge shaped bone, being widest at its medial edge and narrow at its lateral edge. It has three main articular...
Currarino-Silverman syndrome, also known as pectus carinatum type 2 deformity, is a rare disorder in which the patient has a high carinate chest deformity due to a premature fusion of the manubriosternal joint and sternal ossification centres. Congenital heart diseases have been described in mor...
The curtain sign (or draped curtain sign) in neuroimaging refers to the appearance of a vertebral body mass that extends to the anterior epidural space.
The posterior longitudinal ligament is strongly attached to the posterior vertebral body cortex in the midline and is more loosely attached la...
Cutaneous and subcutaneous metastases are not uncommon, occurring in ~5% (range 0.7-10.4%) of internal malignancies, and representing 2% of skin cancers. Sister Mary Joseph nodule is a well known cutaneous metastases.
These metastases can come from haematogenous or lymphatic spread, ...
Cutis laxa is a rare dermatological condition, characterised by elastic fibre loss, resulting in very lax skin. Patients can also develop emphysema.
Cutis laxa may be inherited (autosomal dominant, autosomal recessive, or X-linked recessive) or may occur sporadically.
A cyamella is a rare sesamoid bone that exists as a normal variant within the popliteus tendon, characteristically located at the lateral aspect of the distal femur in the popliteal groove.
Cyamella is best seen on the AP view of plain radiograph as opposed to fabella, which is best appreciated...
The cyclops lesion, also known as localised anterior arthrofibrosis, is a painful anterior knee mass that arises as a complication of anterior cruciate ligament (ACL) reconstruction, although has rarely been reported in patients with ACL injuries that have not been reconstructed.
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 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...
Danon disease is an X-linked dominant cause of debilitating cardioskeletal myopathy.
Although considered rare, the exact incidence is unknown 1.
Danon disease is characterised by the triad of 1-4:
the most prominent clinical feature, and ma...
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 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 separate article...
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....
Densitometric vertebral fracture assessment (VFA) is an image of the lumbar and thoracic spine acquired on dual energy x-ray absorptiometry (DXA) scanners, for the purpose of diagnosing osteoporotic vertebral fractures.
The technique is available on DXA scanners under a variety of...
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 bone lesion is an essential skill for the radiologist, used to form an accurate differential diagnosis for neoplastic entities, and occasionally non-neoplastic. In addition to patient demographics, the radiographic features of a bone lesion are often the primary determinant of non-h...
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) (or in older texts congenital dislocation of the hip (CDH)) 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 lig...
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...
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 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...
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%, 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...
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...