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.

41 results found
Article

Aberrant left pulmonary artery

Aberrant left pulmonary artery, also known as pulmonary sling, represents an anatomical variant characterised by the left pulmonary artery arising from the right pulmonary artery and passing above the right main bronchus and in between the trachea and oesophagus to reach the left lung. It may le...
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Accessory occipital bone sutures

The parietal and occipital bones in particular are common regions for accessory sutures because of their multiple ossification centres. The occipital bone has complex development, ossifying from six centres. The foramen magnum is surrounded by four ossification centres. On each side are the exo...
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Anatomy curriculum

The anatomy curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core anatomy knowledge for radiologists and imaging specialists. General anatomy Neuroanatomy Head and neck anatomy Thoracic anatomy Abdominal and pelvic anatomy Spinal anat...
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Anterior humeral line

The anterior humeral line is key to demonstrating normal elbow alignment and should be used whenever reading a paediatric elbow radiograph to exclude a subtle supracondylar fracture. The rule A line drawn down the anterior surface of the humerus should intersect the middle third of the capitel...
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Apophysis of the proximal 5th metatarsal

The apophysis of the proximal 5th metatarsal lies laterally and is oriented longitudinally parallel to the shaft. Apophysis of the fifth metatarsal base appears on plain radiographs at age 12 for boys and 10 for girls. Fusion of the apophysis to the metatarsal base usually occurs within the fol...
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Asplenia

Asplenia refers to absence of the spleen thereby leading to deficient splenic function. Epidemiology Seen in 3% of neonates with structural heart disease and in 30% of patients who die from cardiac malposition. The male-to-female ratio is 2:1. Pathology Asplenia can be classified into two  t...
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Block vertebra

Block vertebra is a type of vertebral anomaly where there is a failure of separation of two or more adjacent vertebral bodies. Pathology In a block vertebra, there is partial or complete fusion of adjacent vertebral bodies. Associations there is a frequent association with hemivertebrae/abse...
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Butterfly vertebra

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. Pathology Associations an anterior spina bifida, with or without an anterior meningocele can be part of...
Article

Canal of Nuck

The canal of Nuck is an abnormal patent pouch of parietal peritoneum extending anteriorly from the round ligament of the uterus into the labia majora through the inguinal ring into the inguinal canal. Incomplete obliteration of this canal is known as a patent processus vaginalis and can result i...
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Caudothalamic groove

The caudothalamic groove is an important landmark when performing neonatal cranial ultrasound. Gross anatomy As the name suggests, it is located between the caudate nucleus and thalamus, and is a shallow groove projecting from the floor of the lateral ventricle. It is approximately at the leve...
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Cerebellar agenesis

Cerebellar agenesis is a rare congenital abnormality which can result from failure to develop normal cerebellar tissue or destruction of normally developed tissue. For a more general overview of cerebellar malformations, please refer to the article on classification systems for malformations of...
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Congenital portosystemic shunt

​Congenital portosystemic shunts are rare anatomical abnormalities linked to abnormal embryological venous development. They can be extrahepatic or intrahepatic. In either case, the underlying abnormality is shunting of blood from the portal venous system to the systemic venous system thus avoid...
Article

Ductus arteriosus

The ductus arteriosum (or arteriosus) is the thick short conduit for blood to bypass the non-ventilated lungs in the fetus. It is located between and connects the proximal left pulmonary artery and the undersurface of the aortic arch distal to the origin of the last branch of the arch, at the ao...
Article

Ectopic ureter

An ectopic ureter is a congenital renal anomaly that occurs as a result of abnormal caudal migration of the ureteral bud during its insertion to the urinary bladder. Normally the ureter drains via the internal ureteral orifice at the trigone of the urinary bladder.  In females, the most common ...
Article

Elbow ossification

Elbow ossification occurs at the six elbow ossification centers in a reproducible order. Being familiar with the order of ossification of the elbow is important in not mistaking an epicodylar fracture for a normal ossification center.  Appearance Order The order of appearances of the elbow os...
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Endochondral ossification

Endochondral ossification describes the process of ossification from mesenchymal cells (stem cells) with a cartilaginous template and is involved in the healing process of fractures. Bone formation occurs at centers of ossification (or ossification centres) which are either primary or secondary...
Article

Fetal circulation

Fetal circulation differs from the adult circulation due to the presence of certain vessels and shunts.  These shunts will close after birth, and most of these fetal vessels will be seen as remnants in the adult circulation. The function of these shunts is to direct oxygen-rich venous blood to ...
Article

Foramen ovale (cardiac)

The foramen ovale (or ovalis) is the opening in the interatrial septum in the fetal heart that allows blood to bypass the right ventricle and non-ventilated lungs, shunted from the right atrium to the left atrium. Specifically it represents the opening between the upper and lower portions of the...
Article

Fossa ovale

The fossa ovale (or ovalis) is the small oval depression in the interatrial septum at the site of the closed foramen ovale, which closes once fetal circulation ceases in the first few minutes of postnatal life. It represents the overlapping primary and secondary septa of the interatrial septum. ...
Article

Heterotaxy syndrome

Heterotaxy syndrome or situs ambiguus (also commonly, but etymologically less correctly, spelled situs ambiguous) is a disturbance in the usual left and right distribution of the thoracic and abdominal organs which does not entirely correspond to the complete or partial mirror image. It occurs ...
Article

Hoffa's fat pad herniation

Hoffa's fat pad herniation is defined as herniation of infrapatellar fat through a defect in the lateral retinaculum. It is an uncommon cause of an anterolateral knee mass often detected at the fully flexed knee 1. Clinical presentation Mainly occurs in preschool-aged and young children as a p...
Article

Incomplete hippocampal inversion

Incomplete hippocampal inversion unsurprisingly describes the situation where the normal inversion of the hippocampus fails to happen during development. Terminology Incomplete hippocampal inversion is the most correct description of this finding. Hippocampal malrotation is a term used by some...
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Intramembranous ossification

Intramembranous ossification describes the process of ossification from mesenchymal cells (stem cells) without a cartilaginous template and is involved in the healing process of fractures. The stages of intramembranous ossification osteogenesis are as follows: mesenchymal cells differentiate in...
Article

Kump's bump

Kump's bump is a superior convexity of the growth plate located in the anteromedial quadrant of the distal tibia physis, which is the first site of physeal fusion. Closure usually occurs at about 12-13 years of age. The Kump's bump should not to be mistaken for a fracture or abnormal physeal fus...
Article

Meckel diverticulum

Meckel diverticulum is a congenital intestinal diverticulum due to fibrous degeneration of the umbilical end of the omphalomesenteric (vitelline) duct that occurs around the distal ileum. It is considered the most common structural congenital anomaly of the gastrointestinal tract. Epidemiology ...
Article

Mendosal suture

The mendosal suture (also known as the accessory occipital suture) is a normal calvarial suture. Gross anatomy The suture extends through the occipital bone, lying superior to the occipitomastoid suture and inferomedial to the lambdoid suture. It closes in utero or in the first few days of lif...
Article

Neurenteric canal of Kovalevsky

The neurenteric canal or canal of Kovalevsky is the transient communication of the amnion through notochordal canal to the yolk sac during notochordal formation at day 16-17. Abnormalities during this stage produce the neurenteric cyst spectrum.
Article

Omega sign (disambiguation)

The omega sign can refer to a number of different anatomical structures or signs: omega sign (epiglottitis) omega sign (hand bump on the precentral gyrus)
Article

Orthoroentgenogram

Orthoroentgenogram is a radiographic study used to evaluate anatomic leg length and calculate leg-length discrepancies. This study utilises a long ruler placed on the film, and three radiographs including bilateral hips, knees and ankles. Similar studies used to evaluate true leg length include...
Article

Ossification centres of the elbow

There are six ossification centres of the elbow that appear and develop in a relatively reproducible fashion, and are key to assessment of the paediatric elbow radiograph. Timing of their appearance varies in the literature but an approximation is given below. A useful mnemonic to remember the o...
Article

Ossification centres of the foot

Primary ossification centres present at birth Visible on x-ray from birth: calcaneus: 6 months in utero talus: 7 months in utero cuboid: 9 months in utero metatarsals: 9 weeks in utero phalanges: 3-10 months (proximal to distal) Primary ossification centres developing after birth Become ...
Article

Paediatric kidney size

The paediatric kidneys follow a growth curve. The measurements below are of the longest maximal dimension. Measurements in parentheses are one standard deviation. 0 months 1:  female: 4.15 cm (0.35); male: 4.22 cm (0.32) 2 months: 5.28 cm (0.66) 6 months: 6.15 cm (0.67) 10 months: 6.23 cm (0...
Article

Radiocapitellar line

The radiocapitellar line is one of the key lines used to assess alignment on the elbow radiograph. It is particularly useful in the paediatric setting. The rule A line drawn down the neck of the radius should intersect the capitellum. It is important to ensure that you draw the line down the r...
Article

Renal agenesis

Renal agenesis refers to a congenital absence of one or both kidneys. If bilateral (traditionally known as the classic Potter syndrome) the condition is fatal, whereas if unilateral, patients can have a normal life expectancy.  Epidemiology Unilateral renal agenesis affects approximately 1 in ...
Article

Situs classification

Situs classification can be a daunting topic, but it falls into three main groups : situs solitus: the normal configuration of thoracic and abdominal organs situs inversus: mirror image of normal situs ambiguus: an intermediate configuration with duplication (isomerism) Situs is best thought...
Article

Situs solitus

Situs solitus refers to the normal position of the thoracic and abdominal organs. Radiographic features Plain radiograph On plain radiograph, careful attention should be directed at the location of the aortic arch, gastric fundus, cardiac apex, pulmonary fissures and the branching pattern of ...
Article

Spleen size (paediatric)

The spleen size varies with a child's age. The three numbers below represent the 10th percentile, median, and 90th percentile for the long axis of the spleen (cm) 0-3 months: (3.3, 4.5, 5.8 cm) 3-6 months: (4.9, 5.3, 6.4 cm) 6-12 months: (5.2, 6.2, 6.8 cm) 1-2 years: (5.4, 6.9, 7.5 cm) 2-4...
Article

Sprengel deformity

Sprengel deformity, or congenital elevation of the scapula, is a complex deformity of the shoulder and is the most common congenital shoulder abnormality. An initial diagnosis can often be made on radiography, but CT or MRI is often necessary to evaluate the details of the abnormality. Clinical...
Article

Transverse vaginal septum

Transverse vaginal (transvaginal) septum (TVS) is a type of rare congenital utero-vaginal anomaly (class II under the Rock and Adam classification). Epidemiology It is rare with a frequency of 1 in 70,000 females. Clinical presentation In the case of a complete septum, patients commonly pres...
Article

Vesico-urachal diverticulum

Vesico-urachal diverticulum is one of the congenital urachal remnant abnormalities. Gross anatomy It is the proximal equivalent of a urachal umbilical sinus, representing a result of the failure of the urachus to close at the urinary bladder, forming an out-pouching of variable length from the...
Article

Wolffian duct

The Wolffian duct (also known as the mesonephric duct) is one of the paired embryogenic tubules that drain the primitive kidney (mesonephros) to the cloaca. In both the male and the female the Wolffian duct develops into the trigone of the urinary bladder. Development Female In the female, in...

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