| YS | yellow spot; yolk sac |
|---|---|
| ys | yellow spot; yolk sac |
| YST | yolk sac tumor |
| rami laterales ramorum dorsalium nervorum cervicalium/thoracalium/lumbalium/sac | Lateral branch of dorsal primary rami of spinal nerves. See: lateral branches. (05 Mar 2000) |
|---|---|
| gestational sac | <radiology> Arises from blastocyst which implants into secretory endometrium surrounded by echogenic trophoblast sac size: 6th week = 17mm;, 8th week = 31 mm, fills chorionic cavity by 12th week visualization of gestational sac, relative to beta-hCG levels: transabdominal scan: greater than 1800 IU/l, transvaginal scan: less than 500 IU/l = 20%, 500-1000 IU/l = 80%, greater than 1000 IU/l = 100%, relative to menstrual age, transabdominal scan: earliest by 5.5 weeks (10-12mm), transvaginal scan: routinely seen by 5-5.5 weeks see: double decidual sac (12 Dec 1998) |
| gestation sac | The gestation sac is the fluid-filled sac in which the foetus develops, visible with an ultrasound exam. (09 Oct 1997) |
| vestibular blind sac | <anatomy> The lower extremity of the cochlear duct, occupying the cochlear recess in the vestibule. Synonym: caecum vestibulare, vestibular blind sac. (05 Mar 2000) |
| vitelline sac | <embryology, ornithology> One of the set of extra embryonic membranes, growing out from the gut over the yolk surface, in birds formed from the splanchnopleure, an outer layer of splanchnic mesoderm and an inner layer of endoderm. (18 Nov 1997) |
| pericardial sac | <anatomy> A tough fibrous membrane that envelops and protects the heart. (27 Sep 1997) |
| chorionic sac | 1. Protective membrane around the eggs of insects and fishes. 2. Extraembryonic membrane surrounding the embryo of amniote vertebrates. The outer epithelial layer of the chorion is derived from the tropoblast. (18 Nov 1997) |
| cupular blind sac | The upper blind extremity of the cochlear duct. Synonym: caecum cupulare, cupular blind sac, lagena. (05 Mar 2000) |
| preputial sac | The space between the prepuce and the glans penis. (05 Mar 2000) |
| sac | A pouch or cavity. (09 Oct 1997) |
| heart sac | <anatomy> A double membranous sac which envelops and protects the heart. The layer in contact with the heart is referred to as the visceral layer, the outer layer in contact with surrounding organs is the parietal pericardium. In between the two layers is the pericardial space. (27 Sep 1997) |
| hernial sac | The peritoneal envelope of a hernia. (05 Mar 2000) |
| Hilton's sac | A small diverticulum provided with mucous glands extending upward from the ventricle of the larynx between the vestibular fold and the lamina of the thyroid cartilage; it is a vestigial structure, being a much larger structure interdigitating with the neck musculature in some of the great apes where it serves as a resonating chamber. Synonym: sacculus laryngis, appendix ventriculi laryngis, Hilton's sac, laryngeal pouch. Origin: L. Sacculus (05 Mar 2000) |
| pudendal sac | A pear-shaped encapsulated collection of connective tissue and fat in each labium majus. Synonym: Broca's pouch. (05 Mar 2000) |
| superior recess of lesser peritoneal sac | Pneumoenteric recess, a recess of the embryonic celom between the right lung bud and the gut; it is normally largely obliterated before birth, leaving only the superior recess of the vestibule of the lesser peritoneal sac as a vestige. (05 Mar 2000) |