Items tagged “variant”

559 results found
Article

Discoid meniscus

Discoid menisci are those that have a body that is too wide, usually affecting the lateral meniscus. They are incidentally found in 3-5% of knee MRI examinations.  Epidemiology Discoid menisci are congenital, frequently bilateral (up to 50%) and have been reported in twins, although no genetic...
Article

Ductus diverticulum

Aortic ductus diverticulum is a developmental outpouching of the thoracic aorta which may be mistaken for an acute aortic injury. Gross anatomy It is usually seen at the anteromedial aspect of the aorta at site of the aortic isthmus, where the ligamentum arteriosum attaches. It is also the sit...
Article

Ductus diverticulum

Aortic ductus diverticulum is a developmental outpouching of the thoracic aorta which may be mistaken for an acute aortic injury. Gross anatomy It is usually seen at the anteromedial aspect of the aorta at site of the aortic isthmus, where the ligamentum arteriosum attaches. It is also the sit...
Article

Horseshoe kidney

Horseshoe kidneys are the most common type of renal fusion anomaly. They render the kidneys susceptible to trauma and are an independent risk factor for the development of renal calculi and transitional cell carcinoma of the renal pelvis. Epidemiology Horseshoe kidneys are found in approximate...
Article

Horseshoe kidney

Horseshoe kidneys are the most common type of renal fusion anomaly. They render the kidneys susceptible to trauma and are an independent risk factor for the development of renal calculi and transitional cell carcinoma of the renal pelvis. Epidemiology Horseshoe kidneys are found in approximate...
Article

Glenoid labrum variants

There are a number of glenoid labral variants, whose importance is mainly due to the fact that the unwary may misinterpret them as pathology (e.g. Bankart lesion or labral tear). These include: Buford complex sublabral foramen superior sublabral sulcus pseudo-SLAP lesion
Article

Left-sided superior vena cava

A left-sided superior vena cava (SVC) is the most common congenital venous anomaly in the chest, and in a minority of cases can result in a right-to-left shunt 3,4. Epidemiology A left-sided SVC is seen in 0.3-0.5% of the normal population and in ~5% of those with congenital heart disease 3. I...
Article

Left-sided superior vena cava

A left-sided superior vena cava (SVC) is the most common congenital venous anomaly in the chest, and in a minority of cases can result in a right-to-left shunt 3,4. Epidemiology A left-sided SVC is seen in 0.3-0.5% of the normal population and in ~5% of those with congenital heart disease 3. I...
Article

Sphenoethmoidal air cell

Sphenoethmoidal air cell, also commonly known as the Onodi air cell, is an anatomical variant of the paranasal sinuses, important due to its close proximity to the optic nerve and internal carotid artery. Terminology The sphenoethmoidal air cell is generally defined as the posteriormost ethmoi...
Article

Sphenoethmoidal air cell

Sphenoethmoidal air cell, also commonly known as the Onodi air cell, is an anatomical variant of the paranasal sinuses, important due to its close proximity to the optic nerve and internal carotid artery. Terminology The sphenoethmoidal air cell is generally defined as the posteriormost ethmoi...
Article

Os supratalare

An os supratalare is an accessory ossicle of the foot located at the superior aspect of the talar head or neck. It has a reported incidence of ~1% (range 0.2-2.4%) 1. It is almost always asymptomatic.  Differential diagnosis os supranaviculare is also anatomically seen in close proximity to th...
Article

Os supratalare

An os supratalare is an accessory ossicle of the foot located at the superior aspect of the talar head or neck. It has a reported incidence of ~1% (range 0.2-2.4%) 1. It is almost always asymptomatic.  Differential diagnosis os supranaviculare is also anatomically seen in close proximity to th...
Article

Accessory navicular

An accessory navicular is a large accessory ossicle that can be present adjacent to the medial side of the navicular bone. The tibialis posterior tendon often inserts with a broad attachment into the ossicle. Most cases are asymptomatic but in a small proportion it may cause painful tendinosis d...
Article

Accessory navicular

An accessory navicular is a large accessory ossicle that can be present adjacent to the medial side of the navicular bone. The tibialis posterior tendon often inserts with a broad attachment into the ossicle. Most cases are asymptomatic but in a small proportion it may cause painful tendinosis d...
Article

Pancreatic ducts

The ductal embryology of the pancreas is moderately complicated, leading to a number of anatomical variants of the pancreatic ducts, many of which are clinically significant. Gross anatomy The normal arrangement is for the entire pancreas to be drained via a single duct, to the ampulla of Vate...
Article

Pancreatic ducts

The ductal embryology of the pancreas is moderately complicated, leading to a number of anatomical variants of the pancreatic ducts, many of which are clinically significant. Gross anatomy The normal arrangement is for the entire pancreas to be drained via a single duct, to the ampulla of Vate...
Article

Persistent ossiculum terminale

The ossiculum terminale appears as a secondary ossification center of the dens between 3-6 years and normally fuses by 12 years. Failure of fusion results in a persistent ossiculum terminale (also called Bergmann's ossicle or ossiculum terminale of Bergmann) and is considered a normal anatomical...
Article

Persistent primitive trigeminal artery

Persistent primitive trigeminal artery (PPTA) is one of the persistent carotid-vertebrobasilar anastomoses. It is present in 0.1-0.6% of cerebral angiograms and is usually unilateral. In utero, the trigeminal artery supplies the basilar artery before the development of the posterior communicati...
Article

Persistent primitive trigeminal artery

Persistent primitive trigeminal artery (PPTA) is one of the persistent carotid-vertebrobasilar anastomoses. It is present in 0.1-0.6% of cerebral angiograms and is usually unilateral. In utero, the trigeminal artery supplies the basilar artery before the development of the posterior communicati...
Article

Pneumatized dorsum sella

Pneumatization of the dorsum sella is not uncommon, but needs to be remembered as an unusual site of sinus disease, which otherwise may be mistaken for intracranial of pituitary disease.