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".
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).
type I: small pure cisternal fistula between the vein of Galen (voG) and either the pericallosal arteries (anteri...
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
exudative pleural effusions (least common manifestation)
The yin-yang sign is a radiological sign described in both true and false aneurysms on various imaging modalities.
The yin-yang sign indicates bidirectional flow due to swirling of blood within the (true or false) aneurysm.
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 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 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
elasticity = stress / strain
The units of elasticity are in kPa.
This relationship is fun...
Yunis Varón syndrome is a rare skeletal dysplasia. It is thought to be autosomal recessive.
severe neurologic impairment
diastasis of sutures
absent thumbs and distal phalanges of fingers