Items tagged “variant”

559 results found
Article

Superior vena caval duplication

Superior vena caval (SVC) duplication is the most common form of a left-sided SVC, where the normal right-sided SVC remains. The right SVC, however, can be smaller in approximately two-thirds of such cases 3. Pathology Results from failure of the embryonic left anterior cardiac vein to regress...
Article

Superior vena caval duplication

Superior vena caval (SVC) duplication is the most common form of a left-sided SVC, where the normal right-sided SVC remains. The right SVC, however, can be smaller in approximately two-thirds of such cases 3. Pathology Results from failure of the embryonic left anterior cardiac vein to regress...
Article

Hypertrophied column of Bertin

Columns of Bertin represent the extension of renal cortical tissue which separates the pyramids, and as such are normal structures. They become of radiographic importance when they are unusually enlarged and may be mistaken for a renal mass (renal pseudotumor). Nomenclature of such enlarged col...
Article

Hypertrophied column of Bertin

Columns of Bertin represent the extension of renal cortical tissue which separates the pyramids, and as such are normal structures. They become of radiographic importance when they are unusually enlarged and may be mistaken for a renal mass (renal pseudotumor). Nomenclature of such enlarged col...
Article

Sublabral foramen

A sublabral foramen or hole is simply separation of the labrum from the underlying glenoid. It is a labral variant of no clinical significance and can be confused with a SLAP lesion.  Sublabral foramen are located anterosuperiorly and can extend down to but not below the 3 o'clock position, whi...
Article

Thyroidea ima artery

The thyroidea ima artery is an uncommon variant of the blood supply to the inferior aspect of the thyroid gland. It is reported in ~7.5% (range 1.5-12.2%) of individuals and can arise from: brachiocephalic trunk (most common: 1.9-6.0%) right common carotid artery aortic arch internal thoraci...
Article

Unfused spinous process

Unfused spinous process, which is really failure of fusion of the neural arch, is a relatively common anatomical variant and is part of the spectrum of spina bifida occulta.  This should be differentiated from accessory ossicles of the spinous process, which appear after non-fusion of the secon...
Article

Ureterocele

Ureteroceles represent abnormal congenital dilatation of the distal-most portion of the ureter. The dilated portion of the ureter may herniate into the bladder secondary to the abnormal structure of vesicoureteric junction (VUJ). Epidemiology A ureterocele occurs in about 1 in 5000 to 1 in 120...
Article

Ureterocele

Ureteroceles represent abnormal congenital dilatation of the distal-most portion of the ureter. The dilated portion of the ureter may herniate into the bladder secondary to the abnormal structure of vesicoureteric junction (VUJ). Epidemiology A ureterocele occurs in about 1 in 5000 to 1 in 120...
Article

Vertebral anomalies

The vertebral column is affected by a range of anatomical variants of the body and/or neural arch as well as accessory ossicles. Knowledge of basic vertebral anatomy and ossification is essential for describing and understanding the range of anomalies. Variant anatomy Vertebral body hemiverte...
Article

Vertebral anomalies

The vertebral column is affected by a range of anatomical variants of the body and/or neural arch as well as accessory ossicles. Knowledge of basic vertebral anatomy and ossification is essential for describing and understanding the range of anomalies. Variant anatomy Vertebral body hemiverte...
Case

Diastematomyelia and tethered cord

 Diagnosis certain
Assoc Prof Frank Gaillard
Published 19 May 2008
80% complete
MRI
Case

Diastematomyelia and tethered cord

 Diagnosis certain
Assoc Prof Frank Gaillard
Published 19 May 2008
80% complete
MRI
Article

Mega cisterna magna

Mega cisterna magna refers to a normal variant characterized by a truly focal enlargement of the CSF-filled subarachnoid space in the inferior and posterior portions of the posterior cranial fossa. It is an incidental finding on neuroimaging, and no imaging follow up is necessary.  Epidemiology...
Article

Mega cisterna magna

Mega cisterna magna refers to a normal variant characterized by a truly focal enlargement of the CSF-filled subarachnoid space in the inferior and posterior portions of the posterior cranial fossa. It is an incidental finding on neuroimaging, and no imaging follow up is necessary.  Epidemiology...
Case

Pyramidal thyroid lobe

 Diagnosis certain
Assoc Prof Frank Gaillard
Published 18 Sep 2008
65% complete
CT
Article

Fetal posterior cerebral artery

A fetal (origin of the) posterior cerebral artery is a common variant in the posterior cerebral circulation, estimated to occur in 20-30% of individuals 2. The posterior communicating artery (PCom) is larger than the P1 segment of the posterior cerebral artery (PCA) and supplies the bulk of the...
Article

Persistent proatlantal intersegmental artery

The proatlantal intersegmental artery is also known as the type I proatlantal artery, and is one of the persistent carotid-vertebrobasilar anastomoses. It arises from the internal carotid artery (similar to the hypoglossal artery) but instead of heading for the hypoglossal canal, it joins the ve...
Article

Proatlantal artery

The proatlantal artery is one of the persistent carotid-vertebrobasilar anastomoses, and can be subdivided into two types depending on its origin: type I: (~55%) also known as the proatlantal intersegmental artery arises from the internal carotid artery corresponds to the first segmental art...
Article

Arc of Riolan

The arc of Riolan, also known as the mesenteric meandering artery (of Moskowitz) or central anastomotic mesenteric artery, is an arterioarterial anastomosis between the superior and inferior mesenteric arteries. Gross anatomy It is an inconstant artery that connects the proximal superior mesen...