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.

13,216 results found
Article

Windsock sign (duodenal web)

The windsock sign is a typical appearance of a duodenal web (intraluminal duodenal diverticulum) on upper gastrointestinal contrast series which consists of an intraduodenal barium contrast-filled sac that is surrounded by a narrow lucent line (web or intraluminal mucosal diaphragm) which is wel...
Article

Windswept pelvis

Windswept pelvis fracture is a complex bony pelvic injury caused by a combination of unilateral AP compression (open book) injury with a contralateral lateral compression injury.  It occurs when the internal rotation of one iliac wing causes a unilateral sacral compression fracture, while the s...
Article

Winking owl sign (spine)

The (absent) pedicle sign, also called the winking owl sign, occurs on plain film when a pedicle is absent. The term, winking owl sign, where the missing pedicle corresponds to the closed eye, the contralateral pedicle to the other open eye, and the spinous process to the beak of the animal on ...
Article

Winquist classification of femoral shaft fractures

The Winquist classification of femoral shaft fractures is based on fracture comminution and was proposed by Winquist in 1980. This classification is used with regards to management decision making, in determining whether a fracture requires an intramedullary nail or open reduction.  Type 0: no ...
Article

Wirsungocele

Wirsungocele refers to a cystic dilatation of the pancreatic duct of Wirsung, which is the portion of ventral duct between the dorsal-ventral junction and major duodenal papilla. It is believed to be analogous to choledochocele and santorinicele. Clinical presentation It may be an incidental f...
Article

Wiskott-Aldrich syndrome

Wiskott-Aldrich syndrome (WAS) is a rare immunodeficiency disease with a characteristic phenotype that includes: X-linked recessive petechiae, bloody diarrhea, epistaxis due to thrombocytopenia with small platelets eczema starts in first month of life recurrent infections with encapsulated b...
Article

Woggle technique (interventional procedure)

The Woggle technique is the purse-string suture modified using to close a puncture site after a percutaneous procedure. Techniques common to all procedure include: a purse-string suture is done around the introducer sheath (the short plastic tube placed within a vein or artery) cut the needle...
Article

Wolff-Chaikoff effect

Wolff-Chaikoff effect is an autoregulatory phenomenon, whereby a large amount of ingested iodine acutely inhibits thyroid hormone synthesis within the follicular cells, irrespective of the serum level of thyroid-stimulating hormone (TSH) 1.  Pathology The Wolff-Chaikoff effect is thought to be...
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. It also gives off a lateral branch forming the ureteric bud. In both the male and the female the Wolffian duct develops into the trigone of...
Article

Wolff parkinson white syndrome

The Wolff-Parkinson-White syndrome describes paroxysmal tachydysrhythmias in the presence of a specific accessory pathway (AP) which allows direct electrical connection between the atria and ventricles, which usually exclusively occurs via the atrioventricular node. The accessory pathway is usua...
Article

Wolf-Hirschhorn syndrome

Wolf-Hirschhorn syndrome (WHS) is an extremely rare chromosomal anomaly characterized by partial deletion of the p arm of chromosome 4 (4p16.3). Clinical presentation There is a large clinical spectrum: CNS agenesis of the corpus callosum hypertelorism coloboma seizures 4 craniofacial c...
Article

Wolman disease

Wolman disease is a rare autosomal recessive inborn error of metabolism resulting in the deposition of fats in multiple organs.  Clinical presentation Patients with Wolman disease typically present during the first two months of life with failure to thrive, diarrhea and vomiting. Abdominal dis...
Article

Woodruff plexus

Woodruff plexus is a venous plexus located in the posterior end of the inferior meatus 1. It accounts for between 5-10% of epistaxis and are associated with hypertension. These bleeds typically do not respond to anterior nasal packing.
Article

Words we never use

There are a number of words we never use at Radiopaedia.org. This may be the result of an international consensus on correct spelling, other times it is a local decision about how we can improve consistency on the site. This is separate to the differences between British (UK) and American (US) ...
Article

World Health Organization (WHO)

The World Health Organization (WHO) is an agency of the United Nations (UN) that was established in 1948 and acts as the leader in coordinating global health, especially in relation to the developing world. From a radiology perspective, a key role of the WHO is in spearheading international radi...
Article

World Radiography Day

World Radiography Day (WRD) is an annual event held on November 8th to celebrate the anniversary of the discovery of x-rays by Wilhelm Roentgen, and is organized by the International Society of Radiographers and Radiological Technologists (ISRRT) 1. World Radiography Day occurs simultaneously w...
Article

Wormian bone

Wormian bones (a.k.a. intrasutural bones) is the name given to the additional small bones sometimes found between the cranial sutures of the bones of the skull vault, most commonly in relation to the lambdoid suture. Some reserve the term Wormian bones to just the intrasutural bones proximate to...
Article

Wormian bones (mnemonic)

A mnemonic to remember ten of the numerous conditions associated with Wormian bones is: PORKCHOPS Mnemonic P - pyknodysostosis O - osteogenesis imperfecta R - rickets K - kinky hair syndrome C - cleidocranial dysostosis H - hypothyroidism/hypophosphatasia O - otopalatodigital syndrome ...
Article

Wound dehiscence

Wound dehiscence is a surgical complication whereby there is rupture of a wound along the surgical scar (dehiscence, refers to "splitting open"). This may occur on the skin surface, or along a deeper suture line. Clinical presentation Presentation may be with pain (e.g. sternal dehiscence), or...
Article

Wrisberg rip

Wrisberg rips are longitudinal vertical meniscal tears. They occur at the junction of the ligament of Wrisberg and the posterior horn of the lateral meniscus and are commonly associated with anterior cruciate ligament tears 1. 
Article

Wrist (carpal bridge view)

The carpal bridge view an additional view to the three view series of the wrist and carpal bones. It is used to assess the dorsal aspect of the scaphoid, lunate and the triquetrum. Patient position the patient is seated alongside the table dorsal aspect of affected wrist is placed on the dete...
Article

Wrist (carpal tunnel view)

The carpal tunnel view is an axial projection to demonstrate the medial and lateral prominences and the concavity. It can be utilized to investigate potential hook of hamate, pisiform and trapezium factures. Patient position patient stands with the back facing the table palmar surface of hand...
Article

Wrist (clenched fist view)

The clenched fist view is an additional projection used to evaluate suspected widening of the scapholunate interval, often performed bilaterally it is a functional view that requires the patient to clench both hands.  Patient position patient is seated in front of the table  both hands are pl...
Article

Wrist (horizontal beam lateral view)

The horizontal beam lateral wrist view is a modified lateral projection when performing the three view series of the wrist and carpal bones in trauma. It is the orthogonal projection of the PA wrist without any patient movement, making it the most appropriate projection for patients in pain. Pa...
Article

Wrist (lateral view)

The lateral wrist view is part of a three view series of the wrist and carpal bones. It is the orthogonal projection of the PA wrist. Patient position patient is seated alongside the table the affected arm if possible is flexed at 90° so the arm and wrist can rest on the table abduct the hum...
Article

Wrist ligaments

The intrinsic and extrinsic wrist ligaments play a vital role in the stability of the wrist joint. There are numerous ligaments but included below are the most clinically significant. Wrist ligaments are best assessed with dedicated wrist MRI. Gross anatomy intrinsic ligaments (only attach to ...
Article

Wrist (oblique view)

The oblique wrist view is part of a three view series of the wrist and carpal bones. It is not generally performed in follow-up studies unless specifically requested. Patient position patient is seated alongside the table the affected arm if possible is flexed at 90° so the arm and wrist can ...
Article

Wrist (PA view)

The PA wrist view is part of a three view series of the wrist and carpal bones. Although performed PA the view can often be referred to an AP view. Patient position patient is seated alongside the table the affected arm if possible is flexed at 90° so the arm and wrist can rest on the table ...
Article

Wrist (radial deviation view)

The wrist PA radial deviation view is specialized projection employed to better demonstrate the carpal bones that lay on the ulnar aspect of the wrist. Patient position patient is seated alongside the table the affected arm if possible is flexed at 90° so the arm and wrist can rest on the tab...
Article

Wrist radiograph

Wrist radiographs are ubiquitous in the emergency departments. They are commonly performed in the pediatric and elderly populations after a fall on an outstretched hand as well as in patients after higher force trauma. Moreover, they may be performed as part of a skeletal survey looking for meta...
Article

Wrist radiograph (an approach)

Wrist radiographs are ubiquitous on any night of the week in emergency departments, especially when pavements are icy! Choosing a search strategy and using it consistently is a helpful method to overcome common errors seen in diagnostic radiology. Systematic review Distal radial contour Check...
Article

Wrist radiograph (approach)

Wrist x-rays are commonly used for the assessment of the wrist following trauma. This is usually a fall onto an outstretched hand. Systematic review It is useful to have a systematic approach; I tend to start proximally and work distally looking at structures on both views together: distal ra...
Article

Wrist radiograph (summary approach)

This is a basic article for medical students and other non-radiologists Wrist radiographs are commonly used for the assessment of the wrist following trauma.  Summary approach alignment AP distal radius and ulna have smooth joint surface carpal arcs are smooth carpal bones do not overlap ...
Article

Wrist series

The wrist series is comprised of a posteroanterior, oblique, and lateral projection. The series examines the carpal bones that are consisting of the scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate and hamate. It also examines the radiocarpal and distal radiocarpal joint al...
Article

Wrist series (summary)

This is a basic article for medical students and other non-radiologists A wrist series (or wrist x-ray) may be performed for a multitude of reasons. However, they are most commonly used in the assessment of trauma, by clinical teams within the Emergency Department or Orthopedic service. Refere...
Article

Wunderlich syndrome

Wunderlich syndrome is a rare condition, in which spontaneous nontraumatic renal hemorrhage occurs into the subcapsular and perirenal spaces 2. Clinical presentation Wunderlich syndrome is clinically characterized by Lenk's triad: acute flank pain flank mass hypovolemic shock Pathology Et...
Article

Wyburn-Mason syndrome

Wyburn-Mason syndrome (also known as Bonnet-Dechaume-Blanc syndrome) is a rare, nonhereditary neurocutaneous disorder that typically presents with unilateral vascular malformations that primarily involve the brain, orbits and facial structures. It is currently classified as a craniofacial arteri...
Article

Xanthogranulomatous cholecystitis

Xanthogranulomatous cholecystitis (XGC) is an uncommon inflammatory disease of the gallbladder which may be difficult to differentiate from malignancy, both on imaging and pathologically. It is characterized by presence of multiple intramural nodules. Epidemiology It is seen predominantly in f...
Article

Xanthogranulomatous pyelonephritis

Xanthogranulomatous pyelonephritis (XGP) is a rare form of chronic pyelonephritis and represents a chronic granulomatous disease resulting in a non-functioning kidney. Radiographic features are usually specific. Epidemiology Xanthogranulomatous pyelonephritis is seen essentially in all age gro...
Article

Xanthomatous meningioma

Xanthomatous meningiomas are rare histological variants of meningiomas grouped into the subtype of metaplastic meningiomas, being WHO grade I tumors. They are characterized by cells with a lipid-filled vacuolated cytoplasm. Although reported numbers are too small to confirm that this is definit...
Article

XCCL view

An XCCL view is a supplementary mammographic view. It is a type of exaggerated cranio-caudal view. It is particularly good for imaging the lateral aspect of the breast.  It is often done when a lesion is suspected on a MLO view but cannot be seen on the CC view. In this view, the lateral aspect...
Article

XCCM view

An XCCM view is a supplementary mammographic view. It is a type of exaggerated cranio-caudal view. It is particularly good for imaging the medial portion of the breast. In this view, the medial portion of the breast is placed forward. A negative 15° tube tilt is suggested. An optimal XCCM view ...
Article

Xenon-127

Xenon-127 is a radiopharmaceutical principally used when a performing VQ scan. It is not a widely used alternative to xenon-133 with the main advantage being a higher proton energy allowing for post perfusion scanning.  photon energy: 203 KeV physical half life: 36.3 days
Article

Xenon-133

Xenon-133 is a radiopharmaceutical principally used when a performing VQ scan. Inhalation of this gas can also be used to assess cerebral blood flow. photon energy: 81 KeV physical half-life: 5.27 days biological half-life: 30 seconds normal distribution: lungs <15% of inhaled gas is absorb...
Article

Xerostomia

Xerostomia is the medical term for a dry mouth, and is most commonly due to hyposalivation. Epidemiology Xerostomia is the most frequently observed salivary abnormality in clinical practice 1. Clinical presentation dryness of the mouth uncomfortable swallowing vocalisation difficulties: to...
Article

Xiphisternum

The xiphisternum (also known as the xiphoid process or simply the xiphoid) is the smallest of the three parts of the sternum (manubrium, body or gladiolus and xiphisternum). It arises from the inferior and posterior margin of the sternal body and projects inferiorly. It is a small cartilaginous ...
Article

Xiphoid shape variations

There is considerable anatomic variation in the shape of the xiphoid of the sternum: xiphoid ending is classified as single, double, or triple. xiphoid size varies (e.g. elongated process) xiphoid morphology (e.g. ventral or dorsal deviation, hook-like, reverse S-shape). Clinical presentatio...
Article

X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy is an inherited metabolic peroxisomal disorder and one of the more common leukodystrophies in both children and adults. It is characterized by a lack of oxidation of very long chain fatty acids (VLCFAs) that results in severe inflammatory demyelination typically of ...
Article

X-linked Opitz G/BBB syndrome

X-linked Opitz G/BBB syndrome (XLOS) is an x-linked disorder with a spectrum of congenital anomalies. Anomalies that may be seen are: facial anomalies  ocular hypertelorism prominent forehead widow's peak broad nasal bridge anteverted nares cleft lip and/or palate  laryngotracheoesophage...
Article

X-marks-the-spot sign (large bowel volvulus)

The X-marks-the-spot is a sign of complete bowel volvulus and refers to the crossing loops of the bowel at the site of the transition. It has been reported to improve diagnostic confidence in detecting cecal and sigmoid volvulus. This is in contrast to the split-wall sign which indicates partial...
Article

X-ray artifacts

X-ray artifacts can present in a variety of ways including abnormal shadows noted on a radiograph or degraded image quality, and have been produced by artificial means from hardware failure, operator error and software (post-processing) artifacts.  There are common and distinct artifacts for fi...
Article

X-ray film

X-ray film displays the radiographic image and consists of emulsion (single or double) of silver halide (silver bromide (AgBr) is most common) which when exposed to light, produces a silver ion (Ag+) and an electron. The electrons get attached to the sensitivity specks and attract the silver ion...
Article

X-ray interaction with matter

X-rays in the diagnostic range interact with matter primarily via two processes, which are fundamental in understanding how an image is formed in a radiographic exam. These process are the photoelectric effect  Compton scatter 
Article

X-ray production

X-rays are produced due to sudden deceleration of fast-moving electrons when they collide and interact with the target anode. In this process of deceleration, more than 99% of the electron energy is converted into heat and less than 1% of energy is converted into x-rays. Definitions Generator ...
Article

X-ray quantity and quality

X-ray photon quantity refers to the number of photons produced during an exposure. Factors influencing x-ray quantity includes: peak voltage (kVp): beam quantity is approximately proportional to the square of the tube potential generator type/voltage waveform: reducing ripple increases beam q...
Article

X-rays

X-rays (or much more rarely, x-radiation) represent a form of ionizing electromagnetic radiation. They are produced by an x-ray tube, using a high voltage to accelerate the electrons produced by its cathode. The produced electrons interact with the anode, thus producing x-rays. The x-rays produc...
Article

X-ray tube

An x-ray tube functions as a specific energy converter, receiving the electrical energy and converting it into two other forms of energy: x-radiation and heat. Heat is considered the undesirable product of this conversion process; therefore x-radiation is created by taking the energy from the el...
Article

Yasargil classification of vein of Galen aneurysmal malformations

The Yasargil classification is one of the two common systems for classifying vein of Galen malformations that is currently in use at the time of writing (mid 2016).  Classification type I: small pure cisternal fistula between the vein of Galen (voG) and either the pericallosal arteries (anteri...
Article

Yaws

Yaws, also known as framboesia, is a tropical disease produced by the Treponema pallidum subspecies pertenue. Epidemiology Yaws is a tropical disease. Infections have declined dramatically over the last century, however the disease is still present in several countries in Africa and Asia 1. Y...
Article

Yellow nail syndrome

The yellow nail syndrome (YNS) is a rare disorder principally affecting the lymphatic system. It is characterized by a clinical triad: nail discolouration: yellow slow-growing dystrophic nails (scleronychia) lymphedema (peripheral/primary) pulmonary disease: see yellow nail syndrome (pulmona...
Article

Yellow nail syndrome (pulmonary manifestations)

Pulmonary manifestations of yellow nail syndrome are principally centered around chronic cough effects for recurrent lung infections (bronchiectasis) and pleural effusions. The role of proposed lymphatic impairment could account for the development of pleural effusions and smooth interlobula...
Article

Yin-yang sign (solitary fibrous tumor)

The yin-yang sign is a radiologic appearance described in solitary fibrous tumor of the dura on MR. On T2-weighted images, these tumors have two separate solid components, one that is hyperintense and one that is iso- to hypointense relative to brain parenchyma. Histologically, the former repre...
Article

Yin-yang sign (vascular)

The yin-yang sign, also known as the Pepsi sign, is a radiological sign described in both true and false aneurysms on various imaging modalities. Radiographic features Ultrasound On Doppler ultrasound, the yin-yang sign indicates bidirectional flow due to the swirling of blood within the true...
Article

Yolk sac

Yolk sac is the first anatomical structure identified within the gestational sac. It plays a critical role in embryonal development by providing nutrients, serving as the site of initial hematopoiesis, providing endocrine, metabolic and immunological functions and contributing to the development...
Article

Young and Burgess classification of pelvic ring fractures

The Young and Burgess classification is a modification of the Tile classification 1. It is the recommended 5 and most widely used classification system for pelvic ring fractures. It takes into account force type, severity, and direction, as well as injury instability. Anteroposterior compress...
Article

Young's modulus

Young's modulus is a relationship between elasticity, strain, and stress: elasticity x (change in length / original length) = (force / area) put another way, this is elasticity x (strain) = stress or elasticity = stress / strain Elasticity is measured in kilopascals (kPa). This relationsh...
Article

Young syndrome

Young syndrome shares similar clinical and radiological findings to primary ciliary dyskinesia and cystic fibrosis, however, the underlying pathogenesis is yet to be fully elucidated. Obstructive azoospermia at the level of the epididymis is thought to be the cause of infertility. The commonly r...
Article

Yo-yo reflux

Yo-yo reflux or uretero-ureteral reflux is noted in partial duplication of ureters 1,2. It is the reflux of urine from normal caliber ureter to dilated ureter.  Radiographic features Yo-yo reflux should be suspected when there is asymmetric dilatation of ureters. It can be diagnosed with color...
Article

Y sign (epidural lipomatosis)

The Y sign refers to a common appearance in lumbar epidural lipomatosis where excess fat in the extradural space compresses the dural sac into the shape of the letter "Y". 
Article

Yunis-Varón syndrome

Yunis Varón syndrome is a rare skeletal dysplasia. It is thought to be autosomal recessive. Radiographic features severe neurologic impairment cleidocranial dysplasia absent clavicles macrocrania diastasis of sutures micrognathia absent thumbs and distal phalanges of fingers hypoplasia ...
Article

Zabramski classification of cerebral cavernous malformations

The Zabramski classification of cerebral cavernomas has been proposed as a way of classifying cerebral cavernous malformations, and although not used in clinical practice it is useful in scientific publications that seek to study cavernous malformations. The classification was proposed in 1994 ...
Article

Z deformity

The Z deformity is one of the musculoskeletal manifestation of rheumatoid arthritis in hand: radial deviation at the wrist ulnar deviation of the digits, and often palmar subluxation of the proximal phalanges
Article

Zebra sign (cerebellum)

The zebra sign has been termed to describe the finding of layering of blood in amongst the folia of the cerebellum, particularly in the setting of remote cerebellar hemorrhage.1 This type of hemorrhage is characterized by a streaky pattern, like a zebra's stripes, due to blood spreading in the ...
Article

Zebra spleen

Zebra spleen, also referred to as psychedelic spleen or more correctly inhomogeneous splenic enhancement, refers to the transient heterogeneous parenchymal enhancement of the spleen during the arterial or early portal venous phases of contrast enhancement in CT, MRI, or ultrasound imaging. It i...
Article

Zebra stripes

Zebra stripes/artifacts appear as alternating bright and dark bands in a MRI image. The term has been used to describe several different kind of artifacts causing some confusion. Artifacts that have been described as a zebra artifact include the following: Moire fringes 1,2 Zero-fill artifact...
Article

Zebra stripe sign (bones)

The zebra stripe sign occurs where children with osteogenesis imperfecta have been treated with cyclical bisphosphonate therapy, e.g. pamidronate. When the drug is delivered in cycles, dense bone is formed while treatment is being given. This results in dense stripes across the metaphyses of bon...
Article

Zellweger syndrome

Zellweger syndrome (ZS), also known as the cerebrohepatorenal syndrome, is a multisystem metabolic abnormality. As the name implies it primarily affects the central nervous system, liver and kidneys.  Epidemiology The condition typically presents in neonates with poor feeding and/or seizures. ...
Article

Zenker diverticulum

Zenker diverticulum, also known as a pharyngeal pouch, is a posterior outpouching of the hypopharynx, just proximal to the upper esophageal sphincter through a weakness in the muscle layer called the Killian dehiscence. Epidemiology More than 50% of the affected patients present in 60-80 years...
Article

Zero fill artifact

Zero fill artifact is one of many MRI artifacts and is due to data in the K-space array missing or set to zero during scanning. The abrupt change from signal to no signal results in artifacts in the images showing alternating bands of shading and darkness, often in an oblique direction. A spike...
Article

Zero filling interpolation

Zero filling interpolation (ZIP) is the substitution of zeroes for unmeasured data points in order to increase the matrix size of the new data prior to Fourier transformation of MR data. This results in pixels smaller than the actual resolution of the image. The zero filling occurs in the periph...
Article

Zika virus infection

Zika virus infection is a zoonosis which is associated with congenital birth defects, most famously microcephaly. Epidemiology Zika was once isolated to Africa and Asia, however, it spread to the Americas in the last decade 1. There were thousands of cases confirmed in the Americas in 2018 2. ...
Article

Zimmerman-Laband syndrome

Zimmerman-Laband syndrome is a rare congenital syndrome, characterized primarily by gingival hypertrophy and skeletal abnormalities.  Pathology The molecular basis of the syndrome is currently unknown. An autosomal dominant mutation with a high mutation rate and rare instances of germinal mosa...
Article

Zinc

Zinc (chemical symbol Zn) is a trace element with a key role as a constituent of enzymes, e.g. carbonic anhydrase, and as part of zinc finger proteins, vital for the correct folding of macromolecules, such as DNA. More recently zinc has been found to act as an important cellular messenger 3. Ba...
Article

Zinc toxicity

Zinc toxicity (also rarely known as zincalism) is rare as the body is remarkably efficient at excreting excess zinc. Typically oral zinc poisoning manifests primarily as: acute GI symptoms: vomiting, diarrhea, abdominal pain secondary copper deficiency zinc competes with copper for absorption...
Article

Zinner syndrome

Zinner syndrome is a triad of mesonephric (Wolffian) duct anomalies comprising unilateral renal agenesis, ipsilateral seminal vesicle cyst, and ejaculatory duct obstruction 1. Clinical presentation Patients are typically diagnosed during the 3rd or 4th decade of life and often present with per...
Article

Zipper artifact

In MR imaging, zipper artifact refers to a type of MRI artefact where one or more spurious bands of electronic noise extend perpendicular to the frequency encode direction and is present in all images of a series.         There are various causes for zipper artifacts in images. Most of them are...
Article

Zollinger-Ellison syndrome

Zollinger-Ellison syndrome (ZES) is a clinical syndrome that occurs secondary to a gastrinoma.  Clinical presentation Diagnosis of ZES is often delayed by 5-7 years after the onset of symptoms 2.  Pathology Gastrinomas are usually multiple and typically located in the duodenum (more common) ...
Article

Zona orbicularis

The zona orbicularis are circular fibers of the hip joint capsule and form a collar around the femoral neck. Though partly blended with the pubofemoral and ischiofemoral ligaments, these fibers are not directly attached to bone. 
Article

Z-score

Z-scores are a way to translate individual data points into terms of a standard deviation.  Z = (X - Xbar) / σ X: individual data point Xbar: the arithmetic mean σ: the standard deviation The purpose of the Z-score is to allow comparison between values in different normal distributions. Two...
Article

Zuckerkandl tubercle

Zuckerkandl tubercles are the projections of normal thyroid tissue from the posterior or posteromedial margin of the thyroid gland that extend posterior to the tracheoesophageal groove. They are present in most patients and occur more commonly on the right and in the longitudinal center 50% of t...
Article

Zuelzer-Wilson syndrome

Zuelzer-Wilson syndrome, also known as total colonic aganglionosis, is a subset of Hirschsprung disease, in which the whole colon is aganglionic. Epidemiology It is uncommon and accounts for 2-13% of cases of Hirschsprung disease 3,7. Compared with Hirschsprung disease which has a marked male ...
Article

Zurich pituitary score

The Zurich pituitary score (ZPS) is a quantitative classification of pituitary adenomas based on coronal T1W magnetic resonance imaging with contrast, although the score can also be obtained with computed tomography. The ZPS is based on the ratio (R) between horizontal tumor diameter over inter...
Article

Zygoma

The zygoma (also known as zygomatic bone or malar bone) is an important facial bone which forms the prominence of the cheek. It is roughly quadrangular in shape. Gross anatomy Zygoma has three surfaces, five borders, and two processes. Surfaces anterolateral surface is convex, pierced at its...

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.