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.
The anterior abdominal wall forms the anterior limit of the abdominal viscera and is defined superiorly by the xiphoid process of the sternum and costal cartilages and inferiorly by the iliac crest and pubic bones of the pelvis.
The anterior abdominal wall has seven layers (from ...
Hesselbach's triangle or the inguinal triangle is a triangular area on the inferior interior aspect of the anterior abdominal wall within the groin.
base: inguinal ligament
lateral border: inferior epigastric vessels
medial border: lateral border of the rectus sheat...
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...
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...
Heberden nodes are a clinical examination sign related to the hands, most commonly found at the dorsolateral aspect of the distal interphalangeal joint (DIPJ) and are a moderate-to-strong marker of osteoarthritis 1-2.
Previously Heberden nodes and DIP osteophytes were thought to be synonymous...
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...
The petrous part of the temporal bone (or more simply petrous temporal bone, PTB) forms the part of skull base between the sphenoid and occipital bones.
The petrous temporal bone has a pyramidal shape with an apex and a base as well as three surfaces and angles:
The frontal bone is a skull bone that contributes to the cranial vault. It contributes to form part of the anterior cranial fossa.
The frontal bone has two portions:
vertical portion (squama): has external/internal surfaces
horizontal portion (orbital): has superior/inferior su...
The lateral pterygoid muscle, also known as pterygoideus externus or external pterygoid muscle, is one of the muscles of mastication.
The lateral pterygoid is a short, thick muscle, somewhat conical in form, which extends almost horizontally, posteriorly and laterally between th...
The squamous part of the temporal bone (or squamous temporalis/squamous temporal bone) is a very thin bone and forms the anterosuperior aspect of the temporal bone.
The squamous temporal bone's outer convex surface provides attachment to the temporalis muscle and forms a boundary...
The body of the sphenoid bone is the midline cubical portion of the sphenoid bone, hollowed by the sphenoid air sinuses.
The body has superior, inferior, anterior, posterior, and lateral surfaces.
The superior surface features:
ethmoidal spine: prominent spine that articulates...
The sphenofrontal suture is a cranial suture where the frontal bone meets the sphenoid bone bilaterally. From an anterior perspective of the skull, this suture appears in the roof of the bony orbits. From a lateral perspective, it appears as the meeting of the inferoposterior edges of the fronta...
The sphenopetrosal suture is the cranial suture connecting the greater wing of sphenoid with the petrous part of temporal bone in the middle cranial fossa. This fissure forms part of the posterior wall of the foramen lacerum.
Epiphyseal spur refers to spur seen in skeletally mature individuals arising at the level of closed epiphyseal line. It may be seen in any bone containing epiphysis.
The metacarpal index (MCI) is a radiographic measurement that can be used to confirm the presence of disproportionate metacarpal length. It was first introduced by Sinclair in 1960 for the diagnosis of Marfan syndrome 6. The metacarpal index is no longer used for the diagnosis of Marfan syndrome...
Osteoarthritis (OA), or degenerative joint disease (DJD), is the most common of the arthritides.
Because the osteoarthritis is not primarily an inflammatory process, some authors prefer the term osteoarthrosis instead.
Primary OA is the less common variant and is chara...
Bayonet deformity is a term used to describe the shape of the wrist in certain conditions:
hereditary multiple exostosis with pseudo-Madelung deformity
retarded bone growth of the distal ulna with outward bowing of the radius with distal radioulnar joint subluxation
Erosive (inflammatory) osteoarthritis (EOA) is a form of osteoarthritis (OA) where, as the name implies, there is an additional erosive/inflammatory component.
There is marked female predilection (F:M ~12:1), typically presenting in the postmenopausal patient.
Proximal humeral fractures are a heterogeneous group of fractures that include everything from relatively simple transverse fractures of the surgical neck of humerus, to complex, displaced, multi-part fractures of the proximal humerus that extend into the shoulder joint. The shoulder is a hugely...
Shoulder dislocation usually occurs following trauma and results in the humeral head moving out of the glenoid fossa.
This is a summary article. For more information, you can read a more in-depth reference article: shoulder dislocation.
glenohumeral joint ...
Scapholunate advanced collapse (SLAC) refers to a pattern of wrist malalignment that has been attributed to post-traumatic or spontaneous osteoarthritis of the wrist. It is a complication that can occur with undiagnosed or untreated scapholunate dissociation. It is essentially the same sequela o...
Avulsion fracture of the 5th metatarsal styloid, also known as a pseudo-Jones fracture or a dancer fracture, is one of the more common foot avulsion injuries and accounts for over 90% of fractures of the base of the 5th metatarsal.
Despite what should be a simple entity, controversy exists, as ...
Bamboo spine is a radiographic feature seen in ankylosing spondylitis that occurs as a result of vertebral body fusion by marginal syndesmophytes. It is often accompanied by fusion of the posterior vertebral elements as well.
A bamboo spine typically involves the thoracolumbar and/or lumbosacr...
Baastrup syndrome (also referred to as kissing spines) results from adjacent spinous processes in the lumbar spine rubbing against each other and resulting in hypertrophy and sclerosis with focal midline pain and tenderness relieved by flexion and aggravated by extension.
The Scottie dog sign refers to the normal appearance of the lumbar spine when seen on oblique radiographic projection. On oblique views, the posterior elements of the vertebra form the figure of a Scottie dog with:
the transverse process being the nose
the pedicle forming the eye
The anterior tibial translocation sign or anterior drawer sign (a.k.a. anterior translation of tibia) is seen in cases of complete rupture of the anterior cruciate ligament, and refers to anterior translocation (anterior tibial subluxation) of the tibia relative to the femur of more than 7 mm 1.
The anteater nose sign refers to an anterior tubular elongation of the superior calcaneus which approaches or overlaps the navicular on a lateral radiograph of the foot. This fancifully resembles the nose of an anteater and is indicative of calcaneonavicular coalition 1,2.
History and etymolog...
Ankle teardrop sign is one of the radiological signs of an ankle joint effusion. It represents the presence of fluid in the inferior part of the anterior compartment of ankle.
Andersson lesions refer to an inflammatory involvement of the intervertebral discs by spondyloarthritis.
Rheumatic spondylodiscitis is a non-infectious condition that has been shown to occur in about 8% of patients with ankylosing spondylitis, as detected at radiography.
Elbow radiographs are common plain films that are obtained frequently in the emergency department.
anterior humeral line
drawn down the anterior surface of the humerus
should intersect the middle 1/3 of the capitellum
if it does not, think distal humeral fracture...
Proximal femoral fractures are a heterogeneous group of fractures that occur in and around the hip. The commonest type of fracture in this region is the femoral neck fracture.
They can occur anywhere between the joint surface of the femoral head and the upper shaft (proximal diaphysis) of the f...
Pelvic fractures are a heterogeneous group of injuries that can occur secondary to a variety of mechanisms that range from an innocuous simple fall to severe high-energy trauma in a road traffic collision.
This is a summary article. For more information, you can read a more i...
Scaphoid fractures are the second commonest group of fractures that are seen following a fall onto an outstretched hand and result in wrist pain, specifically tenderness in the anatomical snuffbox. They are particularly important because of the risk of avascular necrosis if displaced fractures a...
Distal radial fractures are a relatively common group of injuries that usually occur following a fall. The commonest of these fractures is a transverse extra-articular fracture and where there is associated dorsal angulation, this is termed a Colles fracture.
This is a summar...
Proximal radial fractures are the commonest elbow injury in adult patients and the injury most likely to cause an elbow joint effusion. Radial head and neck fractures are often subtle and may be occult on initial imaging.
This is a summary article. For more information, you c...
Humeral shaft fractures are readily diagnosed and do not usually require internal fixation.
This is a summary article. For more information, you can read a more in-depth reference article: humeral shaft fracture.
3-5% of fra...
The absent bow tie sign represents the loss of the normal appearance of the menisci on parasagittal MRI images, and is suggestive of meniscal injury.
Normally the medial and lateral menisci appear as low signal bow-tie-shaped structures between the femoral condyles and tibial plateaux. As the n...
Clavicle fracture usually occurs following trauma with a direct blow to the shoulder region, often following a fall.
This is a summary article. For more information, you can read a more in-depth reference article: clavicle fracture.
Normal clavicle anatomy
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...
Wrist radiographs are ubiquitous on any night of the week in emergency departments, especially when pavements are icy!
Distal radial contour
Check the contour of the distal radius:
the distal radial articular surface should cup the carpals
the articular surface should ...
The extensor retinaculum is located at the dorsal aspect of the foot and consists of the superior and inferior extensor retinacula.
The superior extensor retinaculum is located proximally to the dorsal aspect of the ankle joint and houses the tibialis anterior, extensor digitoru...
Fibrous dysplasia (FD) is a non-neoplastic tumour-like congenital process, manifested as a localised defect in osteoblastic differentiation and maturation, with the replacement of normal bone with large fibrous stroma and islands of immature woven bone. Fibrous dysplasia has a varied radiographi...
Shorted fetal femur is a morphological descriptor and is usually defined when the femoral length falls below the 5th centile for gestational age (some define it when its under the 2.5th centile 5) or less than 0.91 predicted by the bi-pareital diameter. It can occur in isolated or in association...
Spinal muscular atrophy (SMA) is a type of congenital neuromuscular disease affecting anterior horn cells of the brainstem and spinal cord.
This disorder affects 1 in 6000-10000 infants 1.
The condition typically affects infants and young children, presenti...
Adamantinomas are rare primary malignant bone tumours that in the vast majority of cases occur in the tibia of young patients.
In the past, ameloblastomas, which are benign, locally aggressive bone tumours of the mandible, were also known as adamantinomas of the mandible. The two e...
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. ...
Avascular necrosis (AVN), or more correctly "osteonecrosis", is a generic term referring to an ischaemic death of the constituents of bone. AVN has a wide variety of causes and can affect nearly any bone in the body. Most sites of involvement have an eponym associated with avascular necrosis of ...
A pseudoarthrosis has a differential diagnosis which includes:
failed bone graft
neurofibromatosis type 1 (NF1)
ankylosing spondylitis (post-trauma)
The zygoma (or zygomatic bone) is an important facial bone which forms the prominence of the cheek. It is roughly quadrangular in shape.
Zygoma has three surfaces, five borders, and two processes.
anterolateral surface is convex, pierced at its orbital border by the zy...
Patients with pseudopseudohypoparathyroidism (PPHP) have similar clinical and radiological features as pseudohypoparathyroidism but without alterations in parathyroid hormone levels and calcium metabolism. There is often a family history of pseudohypoparathyroidism.
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 ...
Chronic recurrent multifocal osteomyelitis (CRMO) is an idiopathic inflammatory bone disorder seen primarily in children and adolescents. It is often a diagnosis of exclusion once underlying infection has been ruled out.
There is a female predominance, with 85% of cases reported i...
Spondylodiscitis is characterised by infection involving the intervertebral disc and adjacent vertebrae.
Spondylodiscitis has a bimodal age distribution, which many authors consider essentially as separate entities:
older population ~50 years
Schatzker classification system is one method of classifying tibial plateau fractures.
Increase in type number denotes increasing severity, reflecting not only increased energy imparted to the bone at the time of injury but also an increasingly worse prognosis 1. The most common fracture of the...
The ivory vertebra sign refers to diffuse and homogeneous increase in opacity of a vertebral body that otherwise retains its size and contours, and with no change in the opacity and size of adjacent intervertebral discs.
The cause for an ivory vertebra depends on the age o...
Soft tissue venous malformations, commonly known as soft tissue haemangiomas, are a location-dependent benign vascular soft tissue tumour.
They are the most common angiomatous lesions and represent up to 7% of all benign soft-tissue tumours 2.
It is important to note that accordin...
Parosteal lipomas are rare benign fat-containing tumours closely related to the bone periosteum.
Parosteal lipomas are rare, comprising just 0.3% of all lipomas. They typically occur in 40- to 60-year-old patients.
Patients present with a slowly enlarging,...
Madelung deformity is due to premature closure or defective development of the ulnar third of the distal epiphysis of the radius. This deformity results in a radial shaft that is bowed with increased interosseous space and dorsal subluxation of the distal radioulnar joint.
It can be bilateral ...
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.
Abscesses are focal confined collections of suppurative inflammatory material and can be thought of as having three components 1:
a central core consisting of necrotic inflammatory cells and local tissue
peripheral halo of viable neutrophils
surrounded by a 'capsule' with dilated blood vessel...
Sclerotic or blastic bone metastases can arise from a number of different primary malignancies including 1-4:
prostate carcinoma (most common)
breast carcinoma (may be mixed)
transitional cell carcinoma (TCC)
mucinous adenocarcinoma of the gastroint...
A bunionette also known as a tailor's bunion, is a bony prominence at the lateral 5th metatarsal head and is, therefore, the lateral counterpart of the more common bunion of the first metatarsophalangeal joint.
Bunionettes are visible on clinical examination as an erythe...
A hallux valgus is fixed abduction of the first metatarsophalangeal joint of the great toe. It is usually due to metatarsus primus varus which is medial deviation or adduction of the first metatarsal with an increased first - second metatarsal angle.
The thoracoacromial artery is a vessel arising from the axillary artery at the axilla.
origin: first branch of the second part of the axillary artery 1
supply: pectoralis major and minor, anterior part of the deltoid, and dermal sensation overlying the clavipectoral ...
The anterior humeral circumflex artery is a vessel arising from the axillary artery at the proximal part of the arm. It is smaller in size relative to the posterior humeral circumflex artery.
origin: branch of the axillary artery at the proximal part of the arm
location: proximal arm...
The posterior humeral circumflex artery is a vessel arising from the axillary artery at the proximal part of the arm.
origin: branch of the axillary artery at the proximal part of the arm 1
location: proximal arm
supply: glenohumeral joint, teres major and minor, and deltoid 1
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...
The ligamentum nuchae is a large median ligament composed of tendons and fascia located between the posterior muscles of the neck. It covers the spines of C1 to C6 vertebrae. It is a superior and posterior extension of the supraspinous ligament. It rises from the spinous process of C7 to the ini...
Os odontoideum is an anatomic variant of the odontoid process of C2 and needs to be differentiated from persistent ossiculum terminale and from a type 2 odontoid fracture. It can be associated with atlantoaxial instability.
Although it was originally thought to be a congenital lesion due to a ...
The axis is the second cervical vertebra, commonly called C2. It is an atypical cervical vertebra with unique features and important relations that make it easily recognisable. Its most prominent feature is the odontoid process, which is embryologically the body of the atlas (C1) 1,2. It plays a...
The atlas is the first cervical vertebra, commonly called C1. It is an atypical cervical vertebra with unique features. It articulates with the dens of the axis and the occiput, respectively allowing rotation of the head, and flexion, extension and lateral flexion of the head. Unlike the rest o...
The anterior longitudinal ligament (ALL) arises from the anteroinferior basilar portion of occipital bone, traverses the entire length of the spine, and ends on the anteriosuperior portion of the sacrum.
The ALL runs along the anterior surface of the vertebral bodies (firmly united to the perio...
The occipital bone is a trapezoid skull bone that contributes to the posteroinferior part of the cranial vault. It is pierced by the foramen magnum, permitting communication from the cranial cavity to the vertebral canal
The occipital bone is composed of four parts:
Scurvy (also known as Barlow disease in infants) is a condition characterised by an increased bleeding tendency and impaired collagen synthesis resulting in osteoporosis and impaired wound healing. It is caused by a dietary lack of vitamin C (ascorbic acid).
Scurvy in adults is ra...
Solitary bone plasmacytomas (SBP) may involve any bone, but they have a predisposition for the red marrow-containing axial skeleton:
spinal disease is observed in ~50% (range 34-72%) of cases
the thoracic vertebrae are most commonly involved, followed by lumbar, sacral, and cervical vertebrae
Quadriceps tendon rupture is usually associated with forced flexion of the knee or a direct blow, although spontaneous ruptures are reported.
Predisposing illnesses include:
connective tissue disorders
systemic lupus erythematosus
The ossiculum terminale appears as a secondary ossification centre of the dens between 3-6 years and normally fuses by 12 years. Failure of fusion results in a persistent ossiculum terminale (also called Bergmann's ossicle or ossiculum terminale of Bergmann) and is considered a normal anatomical...
Congenital anomalies of the posterior arch of the atlas (C1) are relatively common anomalies. They may range from partial defects presenting as clefts to complete absence of the posterior arch (aplasia).
These anomalies are classified according to Currarino (see below). It should not be confuse...
Occipital condylar fractures result from high-energy blunt trauma.
The exact incidence of these fractures is unknown but are reported to occur in 3-4% patients with moderate-severe traumatic brain injuries 3.
History and examination are unreliable, and high...
The internal oblique muscle (IOM) is one of the muscles that form the anterior abdominal wall. Inferiorly, it contributes towards the formation of the inguinal ligament.
origin: originates along the whole length of the lumbar fascia, from the anterior two-thirds of the iliac crest and ...
Tophi (plural of tophus), meaning "stone" in Latin appear as lumps on affected joints due to deposit of monosodium rate (MSU) crystals in patients with longstanding high level serum uric acid (hyperuricaemia).
Tophi are a pathognomonic feature of gout.
The transversus abdominis muscle, named according to the direction of its muscle fibres, is one of the flat muscles that form the anterior abdominal wall. It is deep to the internal oblique muscle and ends in the anterior aponeurosis, which ultimately blends with the linea alba.
Intraosseous pneumatocysts are gas containing cystic structures seen inside the bone.
They are of uncertain aetiology. These cysts do not communicate with the joint.
Most common site of involvement is sacroiliac joints. Other sites involved are cervical spine, scapula and ...
Synovial enhancement is an imaging feature typically observed on MRI imaging. It can occur in various forms and can be focal or diffuse.
transient synovitis of the hip
tuberculous septic arthritis...
Synovial haemangiomas are rare benign vascular malformations that occur in relation to the joint. It is sometimes considered a subtype of soft tissue haemangiomas.
The lesions typically present in children and young adults. Occasionally patients can have recurrent haemarthroses 8....
Humeral avulsion of the glenohumeral ligament (HAGL) is, as the name suggests, avulsion of the inferior glenohumeral ligament (IGHL) from its humeral insertion. It can be associated with a bony avulsion fracture in which case it is referred to as bony humeral avulsion of the glenohumeral ligamen...
≤11 ribs is associated with a number of congenital abnormalities and skeletal dysplasias, including:
asphyxiating thoracic dysplasia (Jeune syndrome)
short rib polydactyly syndromes
chromosome 1q21.1 deletion syndrome
Pseudodislocation of the shoulder results from an occult fracture with distension of the glenohumeral joint due to haemarthrosis that causes inferior displacement of the humeral head compared to the glenoid.
This may be mistaken for shoulder joint dislocation. Often, attempts are made to "reloc...
In a shoulder dislocation, there is separation of the humerus from the glenoid of the scapula at the glenohumeral joint.
This article contains a general discussion on shoulder dislocation. For specific dislocation types please refer to the following articles:
anterior shoulder dislocation (95%...
Perthes lesion of the shoulder is one of the types of the anterior glenohumeral injury in which the anterior inferior labrum is torn and lifted from the edge of the glenoid 1 but still attached to the intact lifted periosteum from the anterior aspect of the glenoid. Although the labrum may be no...
Lunate dislocations are an uncommon traumatic wrist injury that require prompt management and surgical repair. The lunate is displaced and rotated volarly. The rest of the carpal bones are in a normal anatomic position in relation to the radius.
These should not be confused with perilunate disl...
Hereditary angiopathy with nephropathy, aneurysms, and muscle cramps (HANAC) syndrome is an autosomal dominant monogenic COL4A1-related disorder.
The exact prevalence is unknown.
The cardinal features of HANAC syndrome are helpfully described in the name of...