Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

2,651 results found
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External oblique muscle

The external oblique muscle (EOM) is one of the muscles that forms the anterior abdominal wall. Its free inferior border forms the inguinal ligament, and its aponeurotic part contributes to the anterior wall of the inguinal canal.  Summary origin: outer surface of the shaft of the lower 8 ribs...
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Extraskeletal chondrosarcoma

Extraskeletal chondrosarcomas make up only 2% of soft-tissue sarcomas  and only 1% of all chondrosarcomas. Pathology  They tend to be of higher grade than run-of-the-mill conventional intramedullary chondrosarcomas, with the majority being of the myxoid (most common) or mesenchymal varieties 3...
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Extraskeletal Ewing sarcoma

Extraskeletal Ewing sarcoma (EES) is included in the Ewing sarcoma family of tumors (ESFT) along with Ewing sarcoma of bone, primitive neuroectodermal tumor (PNET), peripheral neuroepithelioma, and thoracopulmonary PNET (Askin tumour). When compared with Ewing sarcoma of bone, extraskeletal Ewin...
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Extraskeletal musculoskeletal lesions by compartment

Intermuscular extraskeletal myxoid chondrosarcoma fibromatosis ganglion leiomyosarcoma nodular fasciitis neurogenic tumours synovial cyst Intra-articular lipoma arborescens nodular synovitis pigmented villonodular synovitis (PVNS) synovial chondromatosis synovial haemangioma Intram...
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Extra skeletal osteosarcoma

Extraskeletal osteosarcoma (ESOS) is a rare mesenchymal malignant tumour that occurs in the retroperitoneum and soft tissue of extremities without any attachment to bone. Epidemiology ESOS in contrast to other subtypes of osteosarcoma occurs infrequently in individuals under 40 years of age, m...
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Fabella

The fabella is an accessory ossicle typically found in the lateral head of the gastrocnemius. It occurs in ~20% (range 10-30%) of the population 1.  The fabella can also be fibrocartilaginous in nature and is occasionally found in the medial head of the gastrocnemius. The fabella articulates wi...
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Facet dislocation

Facet dislocation refers to anterior displacement of one vertebral body on another. Without a fracture, the only way anterior displacement can occur is by dislocation of the facets.  Facet dislocation can occur to varying degrees: subluxed facets perched facets locked facets The injury usua...
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Facet joint

The facet (or apophyseal or zygapophyseal) joints are the articulations of the posterior arch of the vertebrae and form part of the posterior column.  Gross anatomy They are synovial-lined joints that have a fibrous capsule and connect the articular facets of the vertebrae. The superior facet ...
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Facet joint capsule

Facet joint capsules are the fibrous capsule that surround the vertebral facet or zygapophyseal joints. They are particularly thin and loose, attached to the margins of articular facets on adjoining articular processes. The capsules merge medially with the ligamentum flavum.  In the cervical re...
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Facial muscles

The facial muscles enable facial expression and serve as sphincters and dilators of the orifices of the face. These muscles differ from those of other regions in the body as there is no fascia deep to the skin of the face; many of the facial muscles insert directly into the skin 1. Gross anatom...
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Failed back syndrome

Failed back syndrome refers to persistent leg and/or lumbar back pain after a surgical procedure. The pathophysiology of this syndrome is complex, as often the operation was technically successful.  Terminology Other names for failed back syndrome include failed back surgery syndrome, post-lam...
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Fallen fragment sign

The fallen fragment sign refers to the presence of a bone fracture fragment resting dependently in a cystic bone lesion. This finding is said to be pathognomonic for a simple (unicameral) bone cyst following a pathological fracture. Although it has occasionally been reported with other cystic le...
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Fall onto an outstretched hand

Fall onto an outstretched hand (FOOSH) is a common mechanism for wrist-forearm fractures, in certain cases with involvement of elbow structures, particularly in children. Some injuries that result from such a fall include: Colles fracture Scaphoid fracture Monteggia fracture-dislocation Gal...
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Familial multiple lipomatosis

Familial multiple lipomatosis (FML) is a hereditary syndrome of multiple encapsulated lipomas which are found on the trunk and extremities, with relative sparing of the head and shoulders.  It is clinically distinct from the similarly named multiple symmetric lipomatosis with which it is freque...
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Fanconi anaemia

Fanconi anaemia (FA) is a rare disorder characterised by progressive bone marrow failure, various congenital abnormalities, and predisposition to malignancies (often acute myeloid leukaemia). It is considered the commonest type of inherited marrow failure syndrome 7.  Terminology Fanconi anaem...
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Fascial tail sign

The fascial tail sign is the linear extension along the fascia/muscular aponeurosis from a deeper tumour. Radiographic features It appears as a tail and is best appreciated on MRI, classically seen in desmoid tumours as T2 hypointense bands that progressively enhance particularly on delayed ph...
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Fascicular sign

Fascicular sign is a finding on T2-weighted MRI images that suggests a lesion of neurogenic origin. It is characterised by multiple small ring-like structures with peripheral hyperintensity representing the fascicular bundles within the nerves. It is found in various neurogenic tumours, includi...
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Fatco syndrome

Fatco syndrome is a syndrome consisting of fibular aplasia tibial campomelia and oligosyndactyly. It is a syndrome of unknown genetic basis and inheritance with variable expressivity and penetrance. Differential diagnosis Fuhrmann syndrome and Al-Awadi syndrome are said to be similar to FA...
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Fatigue fracture

Fatigue fractures are a type of stress fracture due to abnormal stresses on normal bone. They should not be confused with an insufficiency fracture, which occurs due to normal stresses on abnormal bone. Plain films typically demonstrate a linear sclerotic region. MRI is the most sensitive and sp...
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Fat pad impingement syndromes of the knee

In fat-pad impingement syndromes the aetiologies are different for each knee fat pad. In anterior suprapatellar fat pad impingment syndrome the cause is usually due to either a developmental cause related to the anatomy of the extensor mechanism, or may be related to abnormal mechanics. In this...
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Fat redistribution syndrome

The fat redistribution syndrome (or HIV lipodystrophy syndrome) is seen in a number of AIDS patients on HAART. It is characterised by typical changes in body fat distribution. Features include : hypertrophy in the neck fat pad (buffalo hump) increased fat in the abdominal region (protease pau...
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Faulty fetal packing

Faulty fetal packing, also known as congenital vault depression, is a congenital concave depression of the skull in a newborn. Epidemiology Occurs in 1 in 10,000 births 1.  Pathology This appearance is due to external compression on the skull from 1,2: fetal limb or twin uterine fibroid b...
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FBI sign

The FBI sign is an acronym referring to the components that form a lipohaemarthrosis. It stands for: fat blood interface
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FCD (disambiguation)

FCD may refer to: focal cortical dysplasia (of the brain) fibrous cortical defect (of the bone)
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Features of a Charcot joint (mnemonic)

The radiographic features of a Charcot joint can be remembered by using the following mnemonic: 6 Ds of Charcot joint Mnemonic increased Density (subchondral sclerosis) Destruction Debris (intra-articular loose bodies) Dislocation Distention Disorganisation The causes of Charcot arthrop...
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Feingold syndrome

Feingold syndrome is characterised by the combination of: microcephaly digital abnormalities alimentary tract atresias especially oesophageal atresia
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Felty syndrome

Felty syndrome comprises of the combination of: rheumatoid arthritis (RA) splenomegaly and neutropaenia It is thought to occur in ~ 1% of patients with rheumatoid arthritis 2. Pathology Serological markers rheumatoid factor (RF): Over 95% of FS patients are positive 5 antinuclear antibod...
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Femoral anteversion

Femoral anteversion refers to the orientation of the femoral neck in relation to the femoral condyles at the level of the knee. In most cases, the femoral neck is oriented anteriorly as compared to the femoral condyles. In the case of posterior orientation, the term femoral retroversion is also ...
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Femoral canal

The femoral canal, or the medial compartment of the femoral sheath, is the inverted cone-shaped fascial space medial to the femoral vein within the upper femoral triangle. It is only 1-2 cm long and opens superiorly as the femoral ring. It serves two purposes: allows the femoral vein to expand ...
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Femoral hernia

Femoral hernias are a type of groin herniation and comprise of a protrusion of a peritoneal sac through the femoral ring into the femoral canal, posterior and inferior to the inguinal ligament. The sac may contain preperitoneal fat, omentum, small bowel, or other structures. Epidemiology There...
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Femoral neck fracture

Neck of femur fractures (NOF) are common injuries sustained by older patients who are both more likely to have unsteadiness of gait and reduced bone mineral density, predisposing to fracture. Elderly osteoporotic women are at greatest risk. Epidemiology It is anticipated that the total number ...
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Femoral nerve

The femoral nerve is a large nerve arising from the lumbar plexus and one of two major nerves supplying the lower limb. Gross anatomy Origin It arises from posterior divisions of L2-L4 roots of the lumbar plexus. Course emerges from the lateral border of the psoas muscle to descend between ...
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Femoral nerve neuropathy

Femoral nerve neuropathy occurs when the femoral nerve is compressed as it passes under the inguinal ligament, anterior to iliopsoas. Causes include surgery (hysterectomy, pelvic, hip, femoral artery catheterization, arterial bypass). Mass effect from iliacus or iliopsoas may be visualised and...
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Femoral ring

The femoral ring is the superior opening of the femoral canal. Its boundaries are: medial: lacunar ligament anterior: medial part of the inguinal ligament lateral: femoral vein within the intermediate compartment of the femoral sheath posterior: pectineal ligament overlying the pectineus and...
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Femoral sheath

The femoral sheath is the funnel-shaped fascial space that extends from the abdomen, inferior to the inguinal ligament, into the femoral triangle. It has variable length and terminates by blending in with the adventitia of the femoral vessels. It is formed from the transversalis and psoas fascia...
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Femoral torsion analysis

Femoral torsion analysis is used to assess the alignment of a femur post surgery. If one side has been operated on it can be compared to the non-operated side. Method Superimpose axial images of: femoral heads the neck of femurs femoral condyles Draw a line from the centre of the femoral h...
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Femoral triangle

The femoral triangle is found in the anterior upper thigh. Gross anatomy Boundaries The major boundaries can be recalled with the mnemonic SAIL 1,2: lateral border: medial border of sartorius medial border: medial border of adductor longus superior border: inguinal ligament floor: iliopso...
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Femoral triangle boundaries (mnemonic)

A mnemonic for the boundaries of the femoral triangle is: SAIL This should be easy to remember because the femoral triangle is shaped like a sail.  Mnemonic S: sartorius A: adductor longus IL: inguinal ligament
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Femoral triangle contents (mnemonic)

Mnemonics to recall the order of the femoral vessels and nerve as they emerge from beneath the inguinal ligament into the femoral triangle are: NAVY NAVEL Mnemonic NAVY From lateral to medial: N: femoral nerve A: femoral artery V: femoral vein Y: "Y-fronts"...
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Femoro-acetabular impingement

Femoro-acetabular impingement (FAI) refers to a clinical syndrome of painful, limited hip motion resulting from certain types of underlying morphological abnormalities in the femoral head/neck region and/or surrounding acetabulum. FAI can lead to early degenerative disease. Epidemiology Pincer...
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Femoroacetabular joint

The femoroacetabular or hip joint is a large ball-and-socket synovial joint between the femoral head and the acetabulum. Summary articulation: ball and socket joint between the head of the femur and the acetabulum ligaments: ischiofemoral, iliofemoral, pubofemoral and transverse acetabular li...
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Femur

The femur (plural: femora) is the longest, most voluminous and strongest bone in the human body. It is composed of the upper extremity, body and lower extremity and provides several muscular origins and insertions. Proximal portion The upper extremity is composed of the head, neck, greater tr...
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Femur sparing intrauterine growth restriction

Femur sparing intrauterine growth restriction is considered by some authors as a particular type of intrauterine growth restriction (IUGR) 1. In this type, the femoral length is the only standard fetal biometric parameter unaffected while all others are reduced.
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Femur x-ray (summary)

A femur x-ray, also known as femur series or femur radiograph, is a set of two x-rays performed of the entire femur. It is performed to look for evidence of injury (or pathology) affecting the humerus. It may be performed as a second test after a hip or knee x-ray has demonstrated a femoral frac...
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Fetal rib fractures

Fetal rib fractures can be caused by certain skeletal dysplasias. These include: osteogenesis imperfecta: type II - one of the classical causes of fetal rib fractures achondrogenesis: type Ia - Houston-Harris sub type
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Fibrodysplasia ossificans progressiva

Fibrodysplasia ossificans progressiva (FOP), previously known as myositis ossificans progressiva (MOP), is a rare, inherited disorder characterised by progressive fibrosis and ossification of muscles, tendons, fasciae, aponeuroses, and ligaments of multiple sites. It is disabling and ultimately ...
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Fibrolipomatous hamartoma of the nerve

A fibrolipomatous hamartoma of the nerve (also known as a neural fibrolipoma) is a benign neoplasm of nerves, resulting from anomalous growth of fibroadipose tissue of the nerve sheath. Pathology Fibrolipomatous hamartoma may be related to hypertrophy of mature fat and fibroblasts in the epine...
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Fibromatosis

Fibromatosis refers to a wide range of soft tissue lesions that share an underlying histopathologic pattern of fibrous tissue proliferation. They can occur in a variety of anatomic sites (e.g. musculoskeletal, abdominopelvic, breast, etc.) and also vary in their behaviour, ranging from indolent/...
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Fibromatosis colli

Fibromatosis colli is a rare form of infantile fibromatosis that occurs within the sternocleidomastoid muscle (SCM). Epidemiology There may be a slight male predilection. It typically presents a few weeks after birth. Clinical presentation Presentation is usually with torticollis and is most...
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Fibrosarcoma of the bone

Fibrosarcoma of the bone is a rare malignant bone tumor which may occur as a primary lesion, or secondarily after radiation treatment, dedifferentiation from other tumors 3 or pathologies such as Paget disease, bone infarction, or chronic osteomyelitis. Terminology It is a distinct entity from...
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Fibrous cortical defect

Fibrous cortical defects (FCD) are benign bony lesions and are a type of fibroxanthoma, histologically identical to the larger non-ossifying fibroma (NOF). Epidemiology Fibrous cortical defects typically occur in children (usually 2-15 years), and indeed are one of the most common benign bony ...
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Fibrous dysplasia

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...
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Fibrous joints

Fibrous joints are a type of joint where the bones are joined by strong fibrous tissue rich in collagen. These joints allow for very little movement (if any) and are often referred to as synarthroses. Examples cranial sutures between bones of the skull gomphosis joints between teeth and alveo...
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Fibrous lesions

The differential for fibrous lesions is wide and includes: non-ossifying fibroma fibrous dysplasia osteofibrous dysplasia / adamantinoma desmoplastic fibroma fibromatoses, e.g.  plantar fibromatosis palmar fibromatosis malignant fibrous histiocytoma / fibrosarcoma dermatofibrosarcoma p...
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Fibroxanthoma of bone

Fibroxanthoma of bone is a confusing term that is sometimes used to encompass non-ossifying fibroma and fibrous cortical defect, and at other times synonymously with just non-ossifying fibromas. As non-ossifying fibroma and fibrous cortical defect are histologically the same, and differ only in ...
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Fibula

The fibula (plural: fibulae) is the smaller of the two bones of the leg. It is not directly involved in the transmission of weight but is important for ankle stability and acts as a source for numerous muscle attachments. It is commonly raised as a flap for reconstructive surgery.  Gross anatom...
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Fibular hemimelia

Fibular hemimelia is a congenital lower limb anomaly characterised by partial or complete absence of fibula and includes a spectrum ranging from mild fibular hypoplasia to complete fibular aplasia 1. Epidemiology Although rare in occurrence, it is the most common congenital absence of long bon...
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Ficat and Arlet classification of avascular necrosis of femoral head

The Ficat and Arlet classification uses a combination of plain radiographs, MRI, and clinical features to stage avascular necrosis of the femoral head. Classification stage 0 plain radiograph: normal MRI: normal clinical symptoms: nil stage I plain radiograph: normal or minor osteopenia ...
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Ficat classification of osteonecrosis

The Ficat classification of osteonecrosis is based on radiographic findings. In 1985 Dr Ficat published a modified version of his initial classification in 1980: Stage 0 preclinical and preradiographic diagnosis is suspected in one hip when the other has a definite disease - this is the stage...
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Fifth lumbar vertebra (L5)

The fifth lumbar vertebra (L5) is the largest of the five lumbar vertebrae and is considered an atypical vertebra due to its shape.  Gross anatomy L5 is the largest, most inferior lumbar discovertebral unit in the vertebral column, and participates in forming the lumbar lordosis (from L1 to L5...
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Filariasis

Filariasis refers to infection with nematodes (roundworms) of the family Filariodidea. There are three types of these thread-like filarial worms: Wuchereria bancrofti: responsible for 90% of cases Brugia malayi: causes most of the remainder of cases B. timori: also causes the disease It can ...
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Finger clubbing

Finger clubbing, also called "drumstick fingers", is a common clinical sign in patients with heart or lung disease. The term is used to describe an enlargement of the distal phalanges of the fingers, giving them a drumstick or club-like appearance.  Pathology The underlying pathogenesis of fin...
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Finger (oblique view)

Finger oblique view is a standard projection for radiographic assessment of the fingers. It is not required for follow-up studies for 'query Foreign Body' unless specifically requested. Patient position patient is seated alongside the table (similar to a projection of hand) from a pronated po...
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Finger (PA view)

Finger PA view is a standard projection for radiographic assessment of the fingers; it is one of three views of the finger series.  Patient position patient is seated alongside the table (similar to the projection of hand) palmar aspect of pronated hand is placed over detector and extended fi...
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Finger series

The finger series is comprised, conventionally of a posteroanterior, oblique and a lateral view. The series examines in detail the distal, middle and proximal phalanx as well as the interphalangeal, metacarpophalangeal and carpometacarpal joints.  Note: the thumb (first digit) reviewed under th...
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Fingers (lateral view)

Finger lateral view is a standard projection for radiographic assessment of the fingers; it is one of three views of the finger series. it is divided into: lateral index and middle fingers lateral of ring and little fingers Patient position Lateral of index and middle fingers patient seated...
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Finger tip lesions (mnemonic)

A mnemonic for finger tip lesions is: GEMS Mnemonic G: glomus tumour  E: epidermoid/enchondroma/subungual exostosis  M: metastasis (almost exclusively lung) S: sarcoidosis
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Finkelstein test

The Finkelstein test is a clinical test used to assess the presence of De Quervain's tenosynovitis in people with wrist pain. It is perfomed by grasping the patients thumb and deviating the hand in the ulnar direction. If a sharp pain occurs along the distal radius this is considered to make de ...
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First metatarsal axis

The first metatarsal axis is represented by a line drawn down the longitudinal axis of the shaft of the first metatarsal. It can be drawn on lateral and DP radiographs and is used to measure the: first metatarsal inclination angle talo-first metatarsal angle
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First rib

The first rib is the most superior of the twelve ribs. It is an atypical rib and is an important anatomical landmark and is one of the borders of the superior thoracic aperture. Gross anatomy Osteology Compared to a typical rib, the first rib is short and thick and it has a single articular f...
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Fishtail deformity (elbow)

Fishtail deformity of the elbow is characterised by a contour abnormality of the distal humerus, which develops when the lateral trochlear ossification centres fails to develop or resorbs.  It is an uncommon complication usually following a distal humeral fracture in childhood. Whilst initially...
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Fish vertebra

The term fish vertebra (also codfish vertebra) describes the biconcave appearance of vertebrae (especially lumbar vertebrae). Pathology osteoporosis  sickle cell disease hereditary spherocytosis homocystinuria renal osteodystrophy osteogenesis imperfecta thalassemia major (rarely) Histo...
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Flail chest

Flail chest or flail thoracic segment occurs when three or more contiguous ribs are fractured in two or more places. Clinically, a segment of only one or two ribs can act as a flail segment, hence there is some controversy between the clinical and radiological definitions. Clinical presentation...
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Flare phenomenon (bone scintigraphy)

Flare phenomenon or osteoblastic flare phenomenon refers to interval visualisation of lesions with a sclerotic rim around an initially lytic lesion or sclerosis of lesions previously undetected on radiograph or CT in the setting of follow-up of an oncological patient with other signs of partial ...
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Flat bones

Flat bones are 1 of the 5 types of bones in the body and represent a group of bones (predominantly of the cranium) that have a relatively flat shape and form from intramembranous ossification.
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Fleck sign (foot)

The fleck sign is a small bony fragment seen in the Lisfranc space (between the base of the 1st and 2nd metatarsal) associated with avulsion of the Lisfranc ligament (at the base of the 2nd metatarsal). It is a very subtle, but important finding, since it predisposes to Lisfranc injury.
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Flexion supracondylar fracture

Flexion supracondylar humeral fractures account for only 2-4% of all supracondylar fractures 1. Unlike the much more common extension supracondylar fracture which are seen in children, flexion fractures are seen in older patients. They are usually the result of a fall directly onto a flexed elbo...
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Flexion tear drop fracture

Flexion tear drop fractures are the most severe fracture of the cervical spine, often causing anterior cervical cord syndrome and quadriplegia. Pathology Mechanism It typically occurs from severe flexion and compression forces, most commonly at C5-6 (e.g. diving head first, motor vehicle coll...
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Flexor carpi radialis

Flexor carpi radialis (FCR) is a muscle found in the first layer of the anterior compartment of the forearm. It does not pass through the carpal tunnel, but rather by itself in a small separate tunnel between the superficial and deep layers of the flexor retinaculum along the scaphoid and trapez...
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Flexor carpi ulnaris

Flexor carpi ulnaris (FCU) is a muscle of the first layer of the anterior compartment of the forearm. Summary origin humeral head: medial epicondyle of the humerus ulnar head: medial border of olecranon and posterior border of ulna insertion: base of 5th metacarpal; hook of hamate, pisiform...
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Flexor digiti minimi brevis

The flexor digiti minimi brevis muscle lies lateral to the abductor digiti minimi. Summary origin: hook of the hamate and flexor retinaculum insertion: proximal phalanx of 5th digit action: flexes 5th finger at metacarpophalangeal joint arterial supply: ulnar artery innervation: deep branc...
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Flexor digiti minimi brevis muscle

The flexor digiti minimi brevis muscle lies under the 5th metatarsal bone. Summary origin: base of metatarsal V and related sheath of fibularis longus tendon insertion: lateral side of base of proximal phalanx of 5th toe action: flexes 5th toe at metatarsophalangeal joint arterial supply: l...
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Flexor digitorum brevis muscle

The flexor digitorum brevis muscle lies immediately superior to the plantar aponeurosis and inferior to the tendons of the flexor digitorum longus in the sole of the foot. Summary origin: medial process of calcaneal tuberosity and plantar aponeurosis insertion: sides of plantar surface of mid...
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Flexor digitorum longus muscle

The flexor digitorum longus (FDL) muscle is located on the tibial side of the leg within the deep posterior compartment of the leg. At its origin it is thin but as it descends, the muscle increases in size. Summary origin: medial side of posterior surface of the tibia insertion: plantar surfa...
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Flexor digitorum profundus

Flexor digitorum profundus (FDP) makes up the third layer of the anterior compartment of the forearm along with flexor pollicis longus. It passes through the carpal tunnel. Summary origin: proximal, anterior surface of ulna and adjacent interosseous membrane insertion: volar surface of distal...
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Flexor digitorum superficialis

Flexor digitorum superficialis (FDS) is a muscle in the second (intermediate) layer of the anterior compartment of the forearm that splits into four tendons, passes under the flexor retinaculum and through the carpal tunnel, to insert into the middle phalanx of the 2nd-4th digits.  Summary ori...
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Flexor hallucis brevis muscle

The flexor hallucis brevis muscle is one of the small muscles of the foot that is involved in flexion of the 1st toe. The hallux sesamoid bones are embedded within its tendon.  Summary origin: plantar surface of cuboid insertion: medial and lateral sesamoid bones of first metatarsal action: ...
Article

Flexor hallucis longus

The flexor hallucis longus (FHL) muscle is one of the muscles of the posterior deep compartment of the leg and along with flexor hallucis brevis, is involved in flexion of the great toe. Its tendon passes between the medial and lateral tubercles of the talus. It's tendon sheath may communicate w...
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Flexor pollicis brevis

The flexor pollicis brevis muscle is distal to the abductor pollicis brevis. Summary origin: tubercle of the trapezium and flexor retinaculum insertion: proximal phalanx of the thumb action: flexes thumb at metacarpophalangeal joint arterial supply: superficial palmar arch innervation: rec...
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Flexor pollicis longus

Flexor pollicis longus (FPL) is one of the two muscles that make up the third layer of the anterior compartment of the forearm along with the flexor digitorum profundus. It is a deep muscle under abductor pollicis brevis muscle. It passes through the carpal tunnel. Summary origin: mid-anterior...
Article

Flexor retinaculum

The flexor retinaculum (also known as the transverse carpal ligament) is a rectangular-shaped fibrous band located at the ventral aspect of the wrist. Gross anatomy On the radial side, it attaches to the scaphoid tubercle and the ridge of the trapezium. On the ulnar side, it attaches to the pi...
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Flexor retinaculum at the ankle

Flexor retinaculum at the ankle is formed by reinforcement of the deep fascia of the leg by transverse collagen bundles and functions to prevent 'bowstringing' of tendons as they pass the tibiotalar joint. It forms the roof of the tarsal tunnel 1, 2. insertions medial malleolus of the tibia m...
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Flip-flop effect

The so-called flip-flop effect refers to a confusing MRI appearance of the skeletal system and subcutaneous tissues. It is seen in a variety of severe fat depletion conditions responsible for diffuse bone marrow serous atrophy and modification or loss of the subcutaneous fat. Not to be confused...

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