Mnemonics to help remember common causes of bony sequestrum include:
E: eosinophilic granuloma
I: infection (Brodie abscess)
L: lymphoma (skeletal)
M: malignant fibrous histiocytoma or metastasis (especially from breast carcinoma)
The skeleton is the complete set of bones that make up a human. There are 206 bones in total which can be divided into:
The proximal femur has four major groups of trabeculae, distributing the compressive and tensile forces from the femoral head into the femoral diaphysis through the femoral neck. Together these trabeculae create the Ward triangle. The individual trabecular groups include:
principal compressive ...
Boogard's angle is measured by drawing a line from basion to opisthion and another line along the plane of the clivus to the basion intersecting the first line - the angle between these two lines is measured .
The normal angle is 126° +/- 6°. If the angle measures more than 136° it is indicativ...
The boomerang sign is defined as a small displaced flap from a longitudinal horizontal type medial meniscal tear which is displaced inferiorly into the medial meniscotibial recess. The imaging diagnosis of this type of tear is crucial because it is normally hidden from the surgeon during routine...
The term Bosworth fracture is no longer used. However, it was classically used to refer to a fracture-dislocation of the ankle in which there was fracture of the fibula and posterior dislocation of the talus.
History and etymology
Named after David M Bosworth (1897-1979), orthopaedic surgeon f...
Both hands series (or both hands x-ray) is an investigation almost exclusively performed in the rheumatology service to assess patients with arthritis. It is not used in trauma.
This is a summary article. For more information, you can read a more in-depth reference article: b...
A botryoid rhabdomyosarcoma is a type of embryonal rhabdomyosarcoma and accounts for 5-10% of all rhabdomyosarcomas 6.
It tends to occur in paediatric population, often between birth and 15 years of age 7.
Rhabdomyosarcomas generally have a nonspecific infiltrative ap...
Bouchard nodes are a clinical sign relating to bony nodules of the the proximal interphalangeal joints, and are much less common than Heberden nodes. They generally (but not always) correspond to palpable osteophytes.
They are sometimes painful, and are typically associat...
Boutonniere deformity is one of the musculoskeletal manifestations of rheumatoid arthritis in the hand with:
flexion contracture of the proximal interphalangeal (PIP) joints
extension of the distal interphalangeal (DIP) joints
The defect appears in the tendon which splays open. The appearanc...
Bowdler spurs refer to transverse long bone midshaft spurs or osteochondral projections associated with hypophosphatasia. They typically occur in the fibulae and less commonly in the forearms.
Bowing fractures are incomplete fractures of tubular long bones in paediatric patients (especially the radius and ulna) that often require no intervention and heal with remodelling.
Bowing fractures are almost exclusively found in children. However, there have been several case re...
Boxer fractures are minimally comminuted, transverse fractures of the 5th metacarpal and are the most common type of metacarpal fracture. They typically occur (as the name suggests) when punching and are a common sight in all emergency departments on Friday nights.
They should not be confused w...
Boxer knuckle (not to be confused with a Boxer fracture) refers to an appearance when there is a disruption to the sagittal bands involving the extensor hood. particularly the sagittal band over the metacarpophalangeal (MCP) joint.
It often tends to result when a clench fisted hand s...
Boyd amputation refers to amputation at the level of the ankle with preservation of the calcaneus and heel pad and consequent fixation of the calcaneus to the tibia. It allows for complete weight bearing and provides both stabilisation of the heel pad and suspension for a prosthesis.
The brachialis muscle (brachialis) is one of the three muscles of the anterior compartment of the arm. It is only involved in flexion at the elbow and therefore the strongest flexor at the elbow, compared with the biceps brachii which is also involved in supination because of its insertion on t...
Brachial plexitis refers to inflammatory change involving the brachial plexus. This is in contrast to a brachial plexopathy meaning any form of pathology involving the brachial plexus.
Brachial plexitis is more commonly seen in men between 30 and 70 years of age and is bilateral i...
The brachial plexus is a complex neural network formed by lower cervical and upper thoracic ventral nerve roots which supplies motor and sensory innervation to the upper limb and pectoral girdle. It is located in the neck extending into the axilla posterior to the clavicle.
Brachial plexus injuries are a spectrum of upper limb neurological deficits secondary to partial or complete injury to the brachial plexus, which provides the nerve supply of upper limb muscles.
Trauma, usually by motor vehicle accidents, involves severe traction on the ...
Mnemonics for brachial plexus terminal branches includes:
Most Alcoholics Must Really Urinate
Where the first letter of each word represents the terminal branches of the brachial plexus:M: musculocutaneous nerveA: axillary nerveM: median nerveR: radial nerveU: ulnar nerve
Brachioradialis is a flexor at the elbow and works with biceps brachii and brachialis. Is it located in the superficial layer of the posterior compartment of the forearm and is particularly useful in elbow stabilisation.
Despite the bulk of the muscle being visible from the anterior surface of ...
Brachycephaly refers to a calvarial shape where the bi-parietal diameter to fronto-occipital diameter approaches the 95th percentile. It can result from a craniosynostosis involving the coronal and lambdoid sutures.
Brachycephaly can be associated with numerous syndrom...
Brachydactyly (BD) essentially refers to short digits. It is often inherited as an autosomal dominant trait (all the types). The clinical spectrum can widely range from minor digital hypoplasia to complete aplasia. As a group, it most commonly involves the middle phalanx 2.
Single or multiple b...
Brachydactyly type A1 or Farabee type brachydactyly is a subtype of brachydactyly. It was the first human anomaly recognised to have a mendelian pattern of inheritance. The anomaly is characterised by hypoplasia or aplasia of middle phalanges of the second to fifth digits in hands and feet and p...
Brachydactyly type A2 or Mohr-Wriedt type is characterised by hypoplasia/aplasia of the second middle phalanx of the index finger, second toe and sometimes little finger. There is radial deviation of the index finger and tibial deviation of the second toe.
Type A2 brachydactyly can b...
Brachydactyly type A3 is characterized by shortening of the middle phalanx of the little finger with radial deviation of distal phalanx. Slanting of the distal articular surface of the middle phalanx leads to radial deflection of the distal phalanx. However it is not always associated with clino...
Brachydactyly type A4 or Temtamy type is characterised by brachymesophalangy (absent or hypoplastic middle phalanx) of the second and fifth fingers. Other less common features include club foot, clinodactyly, ulnar deviation of the second finger.
Like other brachydactyly, type A4 is ...
Brachydactyly type A5 is characterized by absence of the middle phalanges and nail dysplasia with duplicated terminal phalanx of the thumb with resultant bifid thumb. Inheritance is suggested as autosomal dominant.
Brachymetatarsia (a.k.a. congenital short metatarsus) is a rare condition that develops from early closure of the growth plate.
Females are almost exclusively affected 1.
It typically involves the fourth ray or, less frequently, more than one metatarsal bon...
Bridging (or fusion) of the pubic symphysis can be associated with various systemic and local causes, including 1-3:
The bright rim sign in anterior talofibular ligament injury refers to a sign seen on MRI. A cortical defect with a bright dot-like or curvilinear high-signal-intensity, usually at the fibular attachment site, is seen on MRI. It has been described as an indicator of ATFL injury 1.
Brodie abscess is an intraosseous abscess related to a focus of subacute pyogenic osteomyelitis. Unfortunately, there is no reliable way radiographically to exclude a focus of osteomyelitis. It has a protean radiographic appearance and can occur at any location and in a patient of any age. It mi...
Brown adipose tissue (BAT) is one of two types of adipose tissue (the other one being white fat) important for producing thermal energy (heat, non-shivering thermogenesis) especially in the newborn. It constitutes ~5% of body mass in the newborn and tends to disappear in adulthood. It is importa...
Brown tumour, also known as osteitis fibrosa cystica (OFC) or, rarely osteoclastoma, is one of the manifestations of hyperparathyroidism. It represents a reparative cellular process, rather than a neoplastic process. Histologically brown tumours are identical to giant cell tumour (both are osteo...
Brucellosis is a global zoonotic infection secondary to any of the four Brucella spp. that infect humans. It can be focal or systemic, but has a particular affinity for the musculoskeletal system.
Brucellosis occurs worldwide but is particularly prevalent in Mediterranean regions...
Brunelli procedure is a surgical procedure aiming to reconstruct a torn scapholunate ligament by reconnecting the scaphoid and lunate using the flexor carpi radialis tendon 1. In the modified Brunelli technique the tendon is sutured upon itself, thereby preventing the crossing of the distal radi...
Bucket handle fracture may refer to:
bucket handle fracture - non-accidental injury
bucket handle fracture of the pelvis
Buckle rib fractures are typical of an anterior compressive force to the chest, most commonly external cardiac massage, but can be seen following any such traumatic injury.
Buckle rib fractures occur in all ages, even very elderly patients. Thus ribs are not the same as most adult lo...
Buford complex is a congenital glenoid labrum variant where the anterosuperior labrum is absent in the 1-3 o'clock position and the middle glenohumeral ligament is thickened (cord-like) and originates directly from the superior labrum at the base of the biceps tendon and crosses the subscapulari...
Bullet-shaped vertebra refers to the anterior beaking of the vertebral body.
It is seen in the following conditions:
mucopolysaccharidosis (Morquio disease, Hurler disease)
weapons and munitions inspired signs
A bunionette, also known as a tailor's bunion, is a bony prominence at the lateral 5th metatarsal head. It is the lateral counterpart of the more common bunion of the first metatarsophalangeal joint.
Bunionettes are visible on clinical examination as an erythematous swel...
Bursae are small fluid-filled sacs lined by synovial membrane with an inner capillary layer of synovial fluid. It provides a cushion between bones and tendons and/or muscles around a joint. This helps to reduce friction between the bones and allows free movement. They may or may not communicate ...
Bursitis is inflammation of abursa, a synovial membrane-lined space, present overlying a number of joints. The inflammation may be acute or chronic, in the later case calcification may be apparent on plain radiographs. MRI best illustrates the bursa and related pathology.
Specific pathological ...
Burst fractures are a type of compression fracture related to high-energy axial loading spinal trauma that results in disruption of the posterior vertebral body cortex with retropulsion into the spinal canal.
They usually present as back pain and or lower limbs neurologi...
Buschke-Ollendorff syndrome (BOS) comprises of osteopoikilosis associated with disseminated connective tissue and cutaneous yellowish naevi, predominantly on the extremities and trunk 1-2.
Recent genetic work has linked BOS to both isolated osteopoikilosis and melorheostosis 1.
Butterfly fragments are large, triangular fracture fragments seen commonly in comminuted long bone fractures. The term is commonly used in orthopaedic surgery, and results from two oblique fracture lines meeting to create a large triangular or wedge-shaped fragment located between the proximal a...
Butterfly vertebra is a type of vertebral anomaly that results from the failure of fusion of the lateral halves of the vertebral body because of persistent notochordal tissue between them.
an anterior spina bifida, with or without an anterior meningocele
can be part of...
A button sequestrum is a small sequestrum of devascularised bone surrounded by lucency. Although classically described in osteomyelitis and eosinophilic granuloma it is also occasionally seen in fibrosarcoma and lymphoma.
Café au lait spots are a type of pigmented skin lesions which are classically described as being light brown in colour.
Conditions associated with them include:
neurofibromatosis type 1 (NF1)
McCune-Albright syndrome: typically irregular which has been likened to ...
Caffey disease or infantile cortical hyperostosis is a largely self-limiting disorder which affects infants. It causes bone changes, soft-tissue swelling, and irritability.
A rare variant known as prenatal onset cortical hyperostosis is severe and fatal, though it is probably a separate entity ...
Caisson disease is an uncommon diving-related decompression illness that is an acute neurological emergency typically occurring in deep sea divers.
Diving-related decompression illness is classified into two main categories 3:
Arterial gas embolism secondary to pulmonary decompression barotra...
Calcaneal fractures are the most common tarsal fracture, and can occur in a variety of settings.
The calcaneus is the most commonly fractured tarsal bone and accounts for about 2% of all fractures 2 and ~60% of all tarsal fractures 3.
Calcaneal fractures can be divided...
The calcaneal inclination angle is drawn on a weightbearing lateral foot radiograph between the calcaneal inclination axis and the supporting surface.
It is a measurement that reflects the height of the foot framework, but is affected by abnormal pronation or supination of the foot:
The calcaneal inclination axis is drawn between the most inferior portion of the calcaneal tuberosity and the most distal and inferior point of the calcaneus at the calcaneocuboid joint on a weightbearing lateral foot radiograph.
It can be used to draw the calcaneal inclination angle.
A mnemonic for calcaneal lesions is:
B: bone cyst (unicameral)
I: intraosseous lipoma
G: ganglion (intraosseous)
G: giant cell tumour
The calcaneal (Achilles) tendon is the strongest and largest tendon in the foot and even in the human body. But it is commonly injured tendon in the foot owing to scanty vascularity and high pressure upon it. As it carries the whole body weight during standing 2.
The calcaneal te...
Avulsion fractures of the calcaneal tuberosity are rare, accounting for only 3% of all calcaneal fractures. There is a strong association with diabetes, where they may occur spontaneously, and are thought to be due to peripheral neuropathy. They also occur in osteoporosis and hyperparathyroidism...
Calcaneal vascular remnant is a benign finding that may be seen on MRI of ankle and can be misinterpreted as an alarming bone lesion. It is typically located at the insertion site of sinus tarsi ligaments (cervical and interosseous ligaments).
The focus of signal alteration is believed to be pr...
The calcaneofibular ligament (CFL) is the middle ligament of the lateral collateral ligament complex of the ankle and stabilises both the ankle and subtalar joints.
The CFL is an extracapsular round cord measuring 20-25 mm long x 6-8 mm width. Its origin is distal to the anterior...
Calcaneonavicular coalition is one of the two most common subtypes of tarsal coalition, the other being talocalcaneal coalition. As with any coalition it may be osseous (synostosis), cartilaginous (synchondrosis) or fibrous (syndesmosis).
This type of coalition is more ea...
The calcaneus, also referred to as the calcaneum, is the largest tarsal bone and the major bone in the hindfoot. It articulates with the talus superiorly and the cuboid anteriorly and shares a joint space with the talonavicular joint, appropriately called the talocalcaneonavicular joint. The cal...
Calcaneus axial view is part of the two view calcaneus series, this projection is best used to asses the talocalcaneal joint and plantar aspects of the calcaneus. The axial view has a diagnostic sensitivity of 87% for calcaneus fractures 1.
patient is supine or seated with th...
Calcaneus lateral view is part of the two view calcaneus series; this projection is used to assess the calcaneus, talocrural, talonavicular and talocalcaneal joint.
the patient is in a lateral recumbent position on the table
the lateral aspect of the knee and ankle joint shou...
The calcaneus series is comprised of a lateral and axial (plantodorsal) projection. The calcaneus is the most commonly fractured tarsal bone accounting for ~60% of all tarsal fractures 1. This series provides a two view investigation of the calcaneus alongside the talar articulations and talocal...
A calcaneus x-ray, also known as calcaneus series or calcaneus radiograph, is a set of two x-rays of the calcaneus. It is performed to look for evidence of injury (or pathology) affecting the leg, often after trauma.
This is a summary article. For more information, you can re...
The calcar femorale is a normal ridge of dense bone that originates from the postero-medial endosteal surface of the proximal femoral shaft, near the lesser trochanter. It is vertical in orientation, and the ridge projects laterally toward the greater trochanter. This ridge of bone provides mech...
Calcific bursitis is the result of deposition calcium hydroxyapatite crystals. It is closely related to calcific tendinitis, and many authors refer to them as being the same condition.
Calcific myonecrosis refers to a rare post-traumatic phenomenon. It characterised by latent formation of a dystrophic calcified mass occurring almost exclusively in the lower limb (it has been occasionally reported at other sites 5).
Plain radiographs typicall...
Calcific tendinitis (or calcific tendonitis) is a self-limiting condition due to deposition of calcium hydroxyapatite within tendons, usually of the rotator cuff. It is a common presentation of the hydroxyapatite crystal deposition disease (HADD).
Typically this condition affects...
Calcific tendinitis of the longus colli muscles is an inflammatory/granulomatous response to the deposition of calcium hydroxyapatite crystals in the tendons of the longus colli muscle.
This condition typically occurs in adults in middle age (20-50 years of age) with a slight pred...
Calcified intra-articular lesions have a relatively limited differential, including:
impaction fracture fragments
intraarticular avulsion fractures
Calcinosis circumscripta is a condition involving calcium deposition in the subcutaneous tissues, muscles and fascia. It is considered a localised form of calcinosis cutis universalis most often seen in the hands and feet.
Patients present with firm white dermal papules, ...
Calcinosis universalis is a condition characterised by long bands or sheets of symmetrical subcutaneous calcification.
It usually presents <20 years of age, and is more common in women.
palpable calcific plaques in subcutaneous or deeper tissue
fatigue, muscle pain, and...
Calcium pyrophosphate dihydrate disease (CPPD disease), also referred as pyrophosphate arthropathy and perhaps confusingly as pseudogout, is common, especially in the elderly, and is characterised by the deposition of calcium pyrophosphate in soft tissues and cartilage.
CPPD is on...
Calvarial thinning can result from many causes. They include:
craniofacial syndromes 1
focal calvarial thinning
Camptocormia (bent spine syndrome) is a rare syndrome characterised by involuntary flexion of the thoracolumbar spine with weight-bearing which reduces when laying down, and is due to isolated atrophy of the paraspinal muscles.
This condition may be associated
Parkinson disease: ...
Camptodactyly is a clinical or imaging descriptive term where there is a flexion contracture (usually congenital) classically at the proximal interphalangeal joint.
The age of presentation can vary from being detected in utero in an antenatal scan or as an obvious deformi...
Camptodactyly arthropathy coxa vara pericarditis (CACP) syndrome is a rare condition principally characterised by
congenital or early-onset camptodactyly and childhood-onset non-inflammatory arthropathy
coxa vara deformity or other dysplasia associated with progressive hip disease
Camptomelic dwarfism, also known as camptomalic dysplasia, is a rare form of skeletal dysplasia.
Camptomelic dwarfism is rare with an estimated incidence of ~1:200,000 births.
Diagnosis is usually readily made at birth or with antenatal ultrasound. It is...
Camurati-Engelmann disease (CED), also known as progressive diaphyseal dysplasia (PDD), is a rare autosomal dominant sclerosing bone dysplasia. It begins in childhood and follows a progressive course.
Common symptoms include extremity pain, muscle weakness, cranial nerve ...
Canadian C-spine rules are a set of guidelines that help a clinician decide if cervical spine imaging is not appropriate for a trauma patient in the emergency department. The patient must be alert and stable.
There are three rules:
is there any high-risk factor present that requires cervical s...
The capitate (or os magnum) is the largest of the carpal bones and sits at the centre of the distal carpal row. A distinctive head shaped bone, it has a protected position in the carpus.
The capitate sits in a proximo-distal direction with a waist that is proximal to...
Capito-hamate coalition is the second most common type of carpal coalition and represents congenital fusion of the capitate and the hamate. It represents ~5% of all carpal fusions 1 and is associated with Apert syndrome 2.
The capitolunate angle is the angle between the long axis of the capitate and the mid axis of the lunate on the sagittal imaging of the wrist. In a normal situation it should be less than 30o in the resting (neutral) position.
The angle is increased in carpal instability such as with a dorsal i...
There is variation in the relationship between the glenoid labrum and the anterior shoulder joint capsule. This has been divided into three types:
Type 1: capsule inserts into the labrum proper
Type 2: capsule inserts into the base of the labrum, or within 1cm of the base
Type 3: capsule inse...
Carcinogens are substances known to cause cancer. They include:
Nasopharynx / nasal passage
ionising radiation (not technically a substance)
polyaromatic hydrocarbons (PAH)
Carpal angle is defined by two intersecting lines, one in contact with the proximal surface of the scaphoid and the lunate and the other line through proximal margins of the the triquetrum and the lunate. Its normal value is between 130° and 137°.
It is increased in (> 139°)
Carpal bone fractures comprise a range of different fractures which carry varying outcomes. They can involve one or a combination of carpal bones and also be part of fracture-dislocations.
Individual fractures include
scaphoid fracture: 50-80%
lunate fracture: 3.9%
triquetral fracture: ~18%
The carpal bones are the eight bones of the wrist that form the articulation of the forearm with the hand. They can be divided in two rows:
The names and order of these bones can be rememb...
Mnemonics of the carpal bone are numerous and useful for memorising the order and location carpal bones. They usually describe the position of the carpal bones from latera to medial in the proximal row and then the distal row:
Sam Likes To Push The Toy Car Hard
She Looks Too Pretty Try To Catc...
The carpal boss is an unmovable hypertrophied bony protuberance at the base of the second or third metacarpals on the dorsal surface, near the capitate and trapezium.
The condition may represent either or a combination of:
degenerative osteophyte formation
os styloideum (an access...
Carpal coalition refers to fusion of two or more carpal bones, and although the most commonly involved bones are the lunate and triquetrum, most combinations of adjacent bones can be found to be coalesced.
The estimated prevalence is ~0.1% in Caucasian Americans and ~1.5% in Afri...
Carpal height is used to diagnose and assess the severity of carpal collapse. It is defined as the distance between the base of third metacarpal and the subchondral bony cortex of the distal radius. But due to variations between individuals, it is more appropriate to calculate the carpal height ...