Bone mineral density (BMD) is defined as amount of mineral (calcium hydroxyapatite) per unit of bone.
BMD can be measured by various methods:
gamma rays: replaced by radiographic methods
single-energy photon absorptiometry (SPA) was superseded by the introduction of sin...
Bone scans are a nuclear medicine (scintigraphic) study that makes use of Technetium 99m (commonly Tc99m-methylene diphosphonate (MDP)) as the active agent.
The study has three phases which follow intravenous injection of the tracer. Sometimes a fourth (delayed/delayed) phase is performed.
The bones in the upper limb can be divided into those within the arm and pectoral girdle (3), forearm (2) and wrist and hand (27). There are also a number of accessory ossicles, predominantly occurring at the wrist.
Bones of the arm and pectoral girdle
Bones of the...
There are many types of bone within the body:
long bones (longer than they are wide)
short bones (not long bones)
sesamoid bones (for within a tendon)
irregular bones (don't fit into a category)
The majority of the bones of the appendicular skeleton are long bones. However, the ...
There are a bewildering number of bone tumours with a wide variety of radiological appearances:
bone island / enostosis
Bone within a bone is a descriptive term applied to bones that appear to have another bone within them. There are numerous causes including:
thoracic and lumbar vertebrae (neonates and infants)
growth recovery lines (after infancy)
cortical splitting and new periostitis
sickle cell d...
A useful mnemonic to remember the possible aetiologies of a bone within a bone appearance is:
G: growth arrest lines
H: heavy metal, hypoparathryoid, hypothyroid
S: sickle cell anaemia, scurvy, syphilis
T: thalassamia, tuberculosis
D: disease of Caf...
Bony humeral avulsion of the glenohumeral ligament (BHAGL) lesion is just like its slightly shorter relative HAGL lesion, except as the name suggests a bony avulsion fracture is seen at humeral insertion of the inferior glenohumeral ligament.
It is often associated with a subscapularis tear, an...
A mnemonic to help remember bony lesions that have no pain or periostitis is:
F: fibrous dysplasia
U: unicameral bone cyst
N: non-ossifying fibroma
If periostitis or pain is present (assuming no trauma, which can be a foolhardy assumption), you can exclude E-...
The bony pelvis is formed by the sacrum and coccyx and a pair of hip bones (os coxae or innominate bones), comprising the ischium, pubis and ilium and are part of the appendicular skeleton.
Its primary function is the transmission of forces from the axial skeleton to the lower limbs as well as...
The radiological definition of a bony sequestrum refers to an image of calcification within a lucent lesion, completely separated from the surrounding bone and without referring to the histological nature and vascular status of the calcified tissue 1.
The pathological definition of a sequestru...
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...
This is a basic article for medical students and other non-radiologists
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...
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 and rarely as 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 osteocla...
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
Bucket-handle meniscal tears are a type of displaced longitudinal meniscal tear where the inner part is displaced centrally. They are more commonly occur in the medial meniscus and are often associated with anterior cruciate ligament tears.
Bucket-hand tears can man...
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 a bursa, 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.
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.
C7, also known as the vertebra prominens, is the seventh cervical vertebra and looks like vertebra C3-C6, but has some distinct features making it one of the atypical vertebrae. The name vertebra prominens arises from its long spinous process, which is easily palpable.
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. It is also one of the commonest tendons to injure due to its high biomechanical load but poor vascularity 2.
The calcaneal tendon forms by the merging of fibres of the gast...
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...
This is a basic article for medical students and other non-radiologists
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.
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 ...