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.
Inheritance is frequently by autosomal dominant transmission, although cases with recessive inheritance h...
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.
The fascial tail sign is the linear extension along the fascia/muscular aponeurosis from a deeper tumor.
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 pha...
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...
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...
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...
Fatco syndrome is a syndrome consisting of
tibial campomelia and
It is a syndrome of unknown genetic basis and inheritance with variable expressivity and penetrance.
Fuhrmann syndrome and Al-Awadi syndrome are said to be similar to FA...
Fatigue fractures are a type of stress fracture, and are 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 sensiti...
Faulty fetal packing, also known as congenital vault depression, is a congenital concave depression of the skull in a newborn.
Occurs in 1 in 10,000 births 1.
This appearance is due to external compression on the skull from 1,2:
fetal limb or twin
The FBI sign is an acronym referring to the components that form a lipohaemarthrosis. It stands for:
FCD may refer to:
focal cortical dysplasia (of the brain)
fibrous cortical defect (of the bone)
The radiographic features of a Charcot joint can be remembered by using the following mnemonic:
6 Ds of Charcot joint
increased Density (subchondral sclerosis)
Debris (intra-articular loose bodies)
The causes of Charcot arthrop...
Feingold syndrome is characterised by the combination of:
alimentary tract atresias especially oesophageal atresia
Felty syndrome comprises of the combination of:
rheumatoid arthritis (RA)
It is thought to occur in ~ 1% of patients with rheumatoid arthritis 2.
rheumatoid factor (RF): Over 95% of FS patients are positive 5
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 ...
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 ...
A femoral hernia is a type of groin herniation and comprises 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.
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.
It is anticipated that the total number ...
The femoral nerve is a large nerve arising from the lumbar plexus and one of two major nerves supplying the lower limb.
It arises from posterior divisions of L2-L4 roots of the lumbar plexus.
emerges from the lateral border of the psoas muscle to descend between ...
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...
The femoral ring is the superior opening of the femoral canal. It 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 ...
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...
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.
Superimpose axial images of:
the neck of femurs
Draw a line from the centre of the femoral h...
The femoral triangle is found in the anterior upper thigh.
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
A mnemonic for the boundaries of the femoral triangle is:
This should be easy to remember because the femoral triangle is shaped like a sail.
A: adductor longus
IL: inguinal ligament
Mnemonics to recall the order of the femoral vessels and nerve as they emerge from beneath the inguinal ligament into the femoral triangle are:
From lateral to medial:
N: femoral nerve
A: femoral artery
V: femoral vein
Y: "Y-fronts" (i.e. the midline)
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.
The femoroacetabular or hip joint is a large ball-and-socket synovial joint between the femoral head and the acetabulum.
articulation: ball and socket joint between the head of the femur and the acetabulum
ligaments: ischiofemoral, iliofemoral, pubofemoral and transverse acetabular li...
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.
The upper extremity is composed of the head, neck, greater tr...
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.
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...
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
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 ...
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.
Fibrolipomatous hamartoma may be related to hypertrophy of mature fat and fibroblasts in the epine...
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/...
Fibromatosis colli is a rare form of infantile fibromatosis that occurs within the sternocleidomastoid muscle (SCM).
There may be a slight male predilection. It typically presents a few weeks after birth.
Presentation is usually with torticollis and is most...
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.
It is a distinct entity from...
Fibrous cortical defects (FCD) are benign bony lesions and are a type of fibroxanthoma, histologically identical to the larger non-ossifying fibroma (NOF).
Fibrous cortical defects typically occur in children (usually 2-15 years), and indeed are one of the most common benign bony ...
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...
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.
cranial sutures between bones of the skull
gomphosis joints between teeth and alveo...
The differential for fibrous lesions is wide and includes:
osteofibrous dysplasia / adamantinoma
malignant fibrous histiocytoma / fibrosarcoma
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 ...
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.
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.
Although rare in occurrence, it is the most common congenital absence of long bon...
The Ficat and Arlet classification uses a combination of plain radiographs, MRI and clinical features to stage avascular necrosis of the femoral head.
plain radiograph: normal
clinical symptoms: nil
plain radiograph: normal or minor osteopaenia
The Ficat classification of osteonecrosis is based on radiographic findings. In 1985 Dr Ficat published a modified version of his initial classification in 1980:
preclinical and preradiographic
diagnosis is suspected in one hip when the other has a definite disease - this is the stage...
The fifth lumbar vertebra (L5) is the largest of the five lumbar vertebrae and is considered an atypical vertebra due to its shape.
L5 is the largest, most inferior lumbar discovertebral unit in the vertebral column, and participates in forming the lumbar lordosis (from L1 to L5...
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 ...
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 is seated alongside the table (similar to a projection of hand)
from a pronated po...
Finger PA view is a standard projection for radiographic assessment of the fingers; it is one of three views of the finger series.
patient is seated alongside the table (similar to the projection of hand)
palmar aspect of pronated hand is placed over detector and extended fi...
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.
The underlying pathogenesis of fin...
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...
A mnemonic for finger tip lesions is:
G: glomus tumour
E: epidermoid/enchondroma/subungual exostosis
M: metastasis (almost exclusively lung)
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
Lateral of index and middle fingers
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 ...
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
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.
Compared to a typical rib, the first rib is short and thick and it has a single articular f...
The term fish vertebra (also codfish vertebra) describes the biconcave appearance of vertebrae (especially lumbar vertebrae).
sickle cell disease
thalassemia major (rarely)
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...
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.
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 ...
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.
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 Lisfranc's ligament (at the base of the 2nd metatarsal). It is a very subtle, but important finding, since it predisposes to Lisfranc injury.
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...
Flexion tear drop fractures are the most severe fracture of the cervical spine, often causing anterior cervical cord syndrome and quadriplegia.
It typically occurs from severe flexion and compression forces, most commonly at C5-6 (e.g. diving head first, motor vehicle coll...
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...
Flexor carpi ulnaris (FCU) is a muscle of the first layer of the anterior compartment of the forearm.
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...
The flexor digiti minimi brevis muscle lies lateral to the abductor digiti minimi.
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...
The flexor digiti minimi brevis muscle lies under the 5th metatarsal bone.
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...
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.
origin: medial process of calcaneal tuberosity and plantar aponeurosis
insertion: sides of plantar surface of mid...
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.
origin: medial side of posterior surface of the tibia
insertion: plantar surfa...
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.
origin: proximal, anterior surface of ulna and adjacent interosseous membrane
insertion: volar surface of distal...
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.
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.
origin: plantar surface of cuboid
insertion: medial and lateral sesamoid bones of first metatarsal
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...
The flexor pollicis brevis muscle is distal to the abductor pollicis brevis.
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
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.
The flexor retinaculum (also known as the transverse carpal ligament) is a rectangular-shaped fibrous band located at the ventral aspect of the wrist.
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...
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.
medial malleolus of the tibia
Floating meniscus (also known as meniscal avulsion) occurs in acute traumatic settings when the meniscotibial coronary ligaments get disrupted leading to avulsion of the meniscus from the tibial plateau.
Displacement of the meniscus for 5 mm or more from the tibial p...
Flowing ossifications are seen in diffuse idiopathic skeletal hyperostosis (DISH).They are defined as heterotopic ossifications involving the anterior longitudinal ligament, paraspinal connective tissues and annulus fibrosus of at least four contiguous vertebral bodies and are originally describ...
The fluid sign is one of the radiological features of osteoporotic fractures, and can be helpful in distinguishing them from metastatic vertebral fractures, as it is seen more often in osteoporotic fractures and is rarely seen in metastatic fractures 1. It is not as helpful as identifying a para...
Fluid-fluid level containing bone lesions are best seen on MRI, although with narrow window width they can also be appreciated on CT.
Their prevalence is estimated at ~3% of bone and soft tissue tumours 1.
Their presence is non-specific, as they are seen i...
There is a handy mnemonic for fluid-fluid levels of bone lesions on MRI:
G: giant cell tumour
A: aneurysmal bone cyst
T: telangiectatic osteosarcoma
S: solitary bone cyst
Skeletal fluorosis is a chronic metabolic bone disease caused by ingestion of large amounts of fluoride through either water or food in geographic areas where high levels of fluoride occur naturally.
Described features include:
increased bone density: oste...
Focal dermal hypoplasia syndrome is also known as Goltz syndrome, and is named confusingly similar to Gorlin-Goltz syndrome.
A rare disorder that follows X-linked dominant inheritance pattern. More commonly seen in males than female. Worldwide only 200-300 cases have been reported....
Focal fatty deposits/replacement in spinal bone marrow are well-defined focal fat islands within the bone marrow of spine or other parts of axial skeleton.
Common in older individuals, related to age and not related to sex.
This process is a normal variant. Histologica...
Focal periphyseal oedema zones also known as "FOPE" zones are regions of bone marrow oedema seen on MRI that are principally located at the physes about the knee. They are thought to represent potentially painful manifestations of physiologic physeal fusion 1.
FOPE zones are seen ...
A popular mnemonic to help remember causes of focal sclerotic bony lesions is:
H: healed NOF
E: Ewing sarcoma
I: infection or infarct
F: fibrous dysplasia
The dorsoplantar view is part of a three view series examining the phalanges, metatarsals and tarsal bones that make up the foot.
the patient may be supine or upright depending on comfort
the affected leg must be flexed enough that the plantar aspect of the foot is resting o...
The lateral projection is part of the three view series examining the phalanges, metatarsals and tarsal bones that make up the foot.
The lateral projection additionally examines the talocrural joint.
the patient may be supine or upright depending on comfort
the affected le...
The medial oblique projection is part of the three view series examining the phalanges, metatarsals and tarsal bones that make up the foot.
the patient may be supine or upright depending on comfort
the affected leg must be flexed enough that the plantar aspect of the foot is...
The weightbearing dorsiplantar foot radiograph is a specialised projection of the foot. It is key to the assessment of foot alignment and the diagnosis of abnormalities that cause malalignment and foot pain. Nonweightbearing views (e.g. DP foot) are inadequate for the assessment of alignment be...