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22 results found

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


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...

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 ...

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 haemorrhage.1 This type of haemorrhage is characterised by a streaky pattern, like a zebra's stripes, due to blood spreading in th...

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 is...

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...

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...

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 (CNS), liver and kidneys.  Epidemiology The condition typically presents in neonates with poor feeding and/or seiz...

Zenker diverticulum

Zenker diverticulum, also known as a pharyngeal pouch, is an outpouching at the level of the hypopharynx, just proximal to the upper oesophageal sphincter. It is located in the posterior midline at the cleavage plane between the thyropharyngeus muscle and the cricopharyngeus muscle (known as the...

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...

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...

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 high mutation rate and rare instances of germinal mosaic...

Zinner syndrome

Zinner syndrome is a triad of Wolffian duct anomalies that includes unilateral renal agenesis, ipsilateral seminal vesicle cyst, and ejaculatory duct obstruction 1. Clinical presentation Patients are typically diagnosed at 3rd or 4th decade of life and often present with perineal pain, recurre...

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...

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) ...

Zona orbicularis

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

Zuckerkandl tubercle

Zuckerkandl tubercle is a normal variant of the thyroid. It may be mistaken for a thyroid nodule or mass or lymph node.  Zuckerandl tubercle is a projection of normal thyroid tissue from the posterior aspect of the lateral lobes of the thyroid gland.  It is also an important surgical landmark ...

Zuelzer-Wilson syndrome

The Zuelzer-Wilson syndrome (total colonic aganglionosis) is a subset of Hirschsprung disease, in which the whole colon is aganglionic. It is uncommon and accounts for 2-13% of cases of Hirschsprung disease 3. Multiple procedures have been devised to treat the condition, including proctocolectom...


The zygoma (or zygomatic 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: lateral or antero-lateral surface is convex and pierced at its orbital border by the zygomaticofacial foramen which...

Zygomatic arch

The zygomatic arch is formed by the union of the temporal process of the zygomatic bone and the zygomatic process of the temporal bone at the zygomaticotemporal suture.  Related pathology Le Fort type 3 fracture zygomaticomaxillary complex fracture

Zygomaticomaxillary complex fracture

Zygomaticomaxillary complex (ZMC) fractures, also known as a tripod, tetrapod, quadripod, malar or trimalar fractures, are seen in the setting of traumatic injury to the face. They comprise fractures of the: zygomatic arch inferior orbital rim, and anterior and posterior maxillary sinus walls ...

Zygomaticomaxillary suture

The zygomaticomaxillary suture is between the zygomatic process of the maxilla and the maxillary margin of the zygomatic bone.

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