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.

8 results found

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". 

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...

Yellow nail syndrome

The yellow nail syndrome (YNS) is rare disorder principally affecting lymphatic system It is characterised by  nail discolouration: yellow slow growing dystrophic nails peripheral / primary lymphoedema pulmonary manifestations exudative pleural effusions (least common manifestation) bronch...

Yin-yang sign

The yin-yang sign is a radiological sign described in both true and false aneurysms on various imaging modalities.  Radiographic features Doppler sonography The yin-yang sign indicates bidirectional flow due to swirling of blood within the (true or false) aneurysm. Contrast-enhanced CT The ...

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 haematopoiesis, providing endocrine, metabolic and immunological functions and contributing to the developmen...

Young syndrome

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

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 The units of elasticity are in kPa. This relationship is fun...

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 ...

Updating… Please wait.

Alert accept

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

Alert accept Thank you for updating your details.