The Cooke and Newman classification of periprosthetic hip fractures is a modification of the Bethea classification proposed several years earlier.
explosion type fracture, comminuted around the stem of the implant
the prosthesis is always loose and the fracture is inherently unstable
Cookie bite metastases are characterized by small focal eccentric lytic external cortical destruction in long tubular bones.
This type of destruction is typically described for metastases from bronchogenic carcinoma, however they can also occur with other tumors.
Copper beaten skull, also known as beaten silver skull or beaten brass skull, refers to the prominence of convolutional markings (gyral impressions on the inner table of the skull) seen throughout the skull vault.
The appearance of a copper beaten skull is associated with...
The coracoacromial ligament is a flat triangular band that plays a supportive role for the shoulder joint.
originates from the medial border of the acromion
attaches to the lateral border of the coracoid process
overlies the subacromial bursa
indirectly supports the head of th...
The coracobrachialis is one of the three muscles of the anterior compartment of the arm. It sits beneath the biceps brachii, inserting via a flat tendon into the medial shaft of the humerus.
origin: coracoid process of scapula
insertion: via a flat tendon onto the midportion of the medial surf...
The coracoclavicular (CC) distance is an indicator of the integrity of the coracoclavicular (CC) ligament.
The CC distance is assessed on a frontal radiography of the shoulder or clavicle or the coronal projection or a CT or MRI as the distance between the superior cortex...
The coracoclavicular joint is a normal variant of the pectoral girdle, where the conoid tubercle of the clavicle appears enlarged or elongated, with a flattened inferior surface where it approximates the coracoid process of the scapula to form an articulation.
More common in Asia...
The coracoclavicular (CC) ligament is the major vertical stabilising factor of the acromioclavicular joint.
The coracoclavicular ligament can be divided into two parts, the more medial conoid ligament and trapezoid ligament.
origin: knuckle of the coracoid proc...
Coracoclavicular (CC) ligament injury is common with shoulder trauma. It is considered part of the spectrum of acromioclavicular joint injuries 2 and is not often an isolated injury. It is also often injured with clavicular fractures.
This injury is easy to miss, especially with presence of an...
The normal coracohumeral interval measures between 7-11 mm. A measurement less than 6 mm is always considered abnormal 1.
It is usually measured on axial or oblique sagittal CT or MRI 2.
The coracohumeral ligament (CHL) is a strong supportive ligament of the shoulder joint and is a part of rotator cuff interval.
originates from the lateral surface of the base of the coracoid process
runs laterally across the glenohumeral capsule and covers the long head of bicep...
The coracoid process is an anteriorly projecting hook-like process on the superolateral edge of the scapula that projects anterolaterally.
coracobrachialis from the medial apex
short head of biceps brachii from the lateral apex
pectoralis minor from the m...
Coracoid process fractures are an uncommon type of scapular fracture. They do not often occur in isolation and are often associated with acromial, clavicular, or scapular fracture, as well as humeral head dislocation.
In general, the coracoid process tends to fracture at its base and be minimal...
The corduroy sign refers to vertically-oriented, thickened trabeculae seen in intraosseous hemangiomas of the spine. It is the sagittal/coronal equivalent of the polka-dot sign seen on axial imaging.
It is caused by the replacement of the normal cancellous bone by thickened vertical trabeculae...
Coronal balance is one of the features that needs to be assessed on long spine radiographs obtained for spinal deformity, particularly scoliosis. It measures whether or not the upper spine is located over the midline (normal) or off to one side.
To assess coronal balance, a vertical (plumb) li...
Coronal vertebral clefts refer to the presence of radiolucent vertical defects on a lateral radiograph.
It is most often seen in premature male infants 1,3. As they can occur as part of normal variation (especially in the lower thoracic-upper lumbar spine of premature infants) t...
Coronoid process can refer to a number of different anatomical structures:
coronoid process (mandible)
coronoid process (ulna)
Fractures of the coronoid process of the ulna are uncommon and often occur in association with elbow dislocation.
Fracture of the coronoid process is thought to result from elbow hyperextension with either avulsion of the brachialis tendon insertion, or shearing off by th...
Corpectomy (followed by fusion) refers to the removal of one or more vertebral bodies to treat compressive myelopathy caused by extensive hypertrophic osteoarthritis, tumor, infection or severe trauma. In most cases, the intervertebral discs are removed as well 1-3.
An anterior or p...
The corrugator supercilii muscles are two small, triangular muscles that allow facial expression through movement of the eyebrows, including frowning. They are located deep to the frontal part of occipitofrontalis and orbicularis oculi, with which they blend 2.
origin: medial end of th...
The outer shell of compact bone is called cortical bone or cortex.
Cortical bone contains Haversian systems (osteons) which contain a central Haversian canal surrounded by osseous tissue in a concentric lamellar pattern.
Two fibrovascular layers surround the cortical bone which...
Cortical desmoids, also known as cortical avulsive injuries or the Bufkin lesion, are a benign self-limiting entity. This is a classic "do not touch" lesion, and should not be confused with an aggressive cortical/periosteal process (e.g. osteosarcoma).
Cortical desmoid is a misnom...
Costal cartilage fractures are fractures of the cartilage connecting the ribs anteriorly to the sternum.
There is little published data on costal cartilage fractures. Most reported cases are in males and resulted from blunt trauma or a fall 1,2.
In young ch...
The costochondral joints are the joints between each rib and its costal cartilage. They are primary cartilaginous joints. These joints represent the demarcation of the unossified and ossified part of the rib 1. The joint is held together by periosteum, with the lateral aspect of the costal ca...
The costoclavicular ligament or rhomboid ligament is the major stabilising factor of the sternoclavicular joint.
The costoclavicular ligament binds the inferior medial clavicle (via the rhomboid fossa) to the first costal cartilage and adjacent end of the first rib. It is compose...
The costovertebral joint is an articulation between the ribs and the vertebral column.
The ribs articulate with the thoracic vertebrae via two distinctly different joints:
costovertebral joint - articulation between the head of the rib and the vertebral body
The costoxiphoid ligaments, also known as the chondroxiphoid ligaments, are inconstant fibrous structures joining the anterior and posterior surfaces of the xiphoid to the respective surfaces of the adjacent seventh and, occasionally, sixth costal cartilages.
The cotton wool appearance is a plain film sign of Paget disease and results from thickened, disorganized trabeculae which lead to areas of sclerosis in a previously lucent area of bone, typically the skull. These sclerotic patches are poorly defined and fluffy.
Other Paget disease re...
The Coughlin classification is the most widely used to type bunionettes. It relies on simple angle measurements on weightbearing foot radiographs taken in the dorsoplantar projection 1,2. In 2013 DiDomenico et al added type IV 2.
enlarged lateral surface of the head of t...
Cowden syndrome, also known as multiple hamartoma syndrome, is characterized by multiple hamartomas throughout the body and increased risk of several cancers.
Type 2 segmental Cowden syndrome is the association of Cowden syndrome with a Cowden naevus, when it is considered a type o...
Coxa magna is the asymmetrical, circumferential enlargement and deformation of the femoral head and neck. Definitions in the literature vary but enlargement with asymmetry >10% in size is a reasonable cut-off for diagnosis 1.
Coxa plana is flattening of the femoral head epiphysis and is associated with many skeletal disorders:
multiple epiphyseal dysplasia
hemoglobinopathies, e.g. sickle cell anemi...
Coxa profunda refers to a deep acetabular socket. On pelvis x-rays it is seen as the acetabular fossa being medial to the ilioischial line. It should be differentiated from protrusio acetabuli, where the femoral head is seen additionally medial to the ilioischial line. Coxa profunda is much more...
Coxa valga describes a deformity of the hip where there is an increased angle between the femoral neck and femoral shaft.
Coxa valga is often associated with shallow acetabular angles and femoral head subluxation.
neuromuscular disorders, e.g. cerebral palsy
Coxa vara describes a deformity of the hip where the angle formed between the head and neck of the femur and its shaft (Mikulicz angle) is decreased, usually defined as less than 120 degrees.
It can be congenital or acquired. The common mechanism in congenital cases is a failure of m...
Cozen fracture or phenomenon is the valgus angulation deformity of the tibia following a proximal tibial metaphyseal fracture in children.
This typically occurs as a late deformity in children aged 3-6 years.
Proposed causes include:
non-recognised or under ...
Craniofacial fibrous dysplasia is one of four types of fibrous dysplasia and is characterized, as the name suggests, by involvement of the skull and facial bones.
For a general discussion of the underlying pathology, refer to the parent article fibrous dysplasia.
Although the term...
Craniosynostosis refers to the premature closure of the cranial sutures. The skull shape then undergoes characteristic changes depending on which suture(s) close early.
There is a 3:1 male predominance with an overall incidence of 1 in 2000-2500. 8% of cases are syndromic or famil...
Craniotabes is defined as a softening of the skull bones that may be normally present in newborns.
Craniovertebral junction (CVJ) anomalies can be congenital, developmental or due to malformation secondary to any acquired disease process. These anomalies can lead to cranial nerve compression, vertebral artery compression and obstructive hydrocephalus.
The cranio-vertebral junctio...
The crescent sign of avascular necrosis is seen on conventional radiographs and refers to a linear area of subchondral lucency seen most frequently in the anterolateral aspect of the proximal femoral head (which is optimally depicted on the frog-leg radiographic view). It indicates imminent arti...
CREST syndrome (a.k.a. limited systemic sclerosis or limited scleroderma) is a variant of progressive systemic sclerosis (PSS) and stands for
C - Calcinosis
R - Raynaud phenomenon
E - Esophageal dysmotility
S - Sclerodactyly
T - Telangiectasia
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...
Cross over toe deformity is a type of deformity where one toe may deviate medially or laterally crossing another toe.
It has been reported to be more commonly seen in women over the age of 50 years 1, and in patients with hallux valgus.
It can occur if there is a unil...
Crouzon syndrome is rare disorder characterized 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...
CT guided bone biopsy is a type of image guided biopsy.
It may be performed using the 'CT fluoroscopy' capabilities of modern CT scanners or with the traditional step-wise approach.
CT biopsies are usually performed using a co-axial needle technique to gain a stable position through which the ...
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 (also known as ligament or band of Osborne), extends from the olecranon to the medial epicondyle
Cubital tunnel syndrome is a type of ulnar nerve compression neuropathy due to pathological compression of the ulnar nerve along its course within the cubital tunnel.
Compression of the ulnar nerve at the elbow is the second most common peripheral neuropathy of the upper extremity...
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...
Cuboid syndrome is a cause of lateral midoot pain, believed to result from abnormal articulation of the cuboid with the calcaneus (calcaneocuboid joint).
Cuboid syndrome presents with lateral foot pain and swelling, often diffuse and similar to an ankle (ligament) sprain ...
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 centers. Congenital heart diseases have been described in mor...
The curtain sign, also known as the draped curtain sign, in neuroimaging refers to the appearance of a vertebral body mass that extends posteriorly towards the anterior epidural space.
The posterior longitudinal ligament is strongly attached to the posterior vertebral body cortex in the midline...
Cutaneous and subcutaneous metastases are not uncommon, occurring in ~5% (range 0.7-10.4%) of internal malignancies, and representing 2% of skin cancers. The Sister Mary Joseph nodule is a well known cutaneous metastasis.
These metastases can come from haematogenous or lymphatic spre...
Cutis laxa is a rare dermatological condition, characterized by elastic fiber 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 ...
Cyriax syndrome, also known as slipping rib syndrome, occurs when hypermobility of the rib cartilage of the lower ribs slips and moves, leading to pain in lower chest or upper abdomen 1.
This condition may occur at any age, but is reportedly more common in middle-aged adults, and ...
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.
popliteal synovial cyst - Baker's cyst
intra-articular ganglion cyst
ACL ganglion cyst
PCL ganglion cyst
Hoffa fat pad ganglion cyst
extra-articular ganglion cys...
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 characterized by the triad of 1-4:
the most prominent clinical feature, and ma...
A dedifferentiated chondrosarcoma is a combined tumor made up to two components which are often sharply demarcated from one another (thus raising the possibility of it representing a collision tumor).
conventional chondrosarcoma (low grade)
dedifferentiated high grade areas
malignant fibrous ...
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 clots occuring 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 articles....
Degenerative disk 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 of biomechanical stresses and genetic predisposition which alter...
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 anemia, 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.g...
Common causes of dense transverse metaphyseal lines can be remembered using the mnemonics:
D: D-vitamin intoxication
E: elemental arsenic and heavy metals (lead, bismuth, phosphorus)
N: normal variation
S: systemic illness
E: estrogen to mother ...
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 characterized 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 ...