| 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) |
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| pericardial sac | <anatomy> A tough fibrous membrane that envelops and protects the heart. (27 Sep 1997) |
| Gruber's cul-de-sac | A lateral diverticulum in the suprasternal space beside the medial extremity of the clavicle behind the sternal attachment of the sternocleidomastoid muscle. (05 Mar 2000) |
| 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) |
| conjunctival cul-de-sac | The space formed by the junction of the bulbar and palpebral portions of the conjunctiva, that of the upper lid being the fornix conjunctivae superior and that of the lower lid the fornix conjunctivae inferior. Synonym: fornix conjunctivae, conjunctival cul-de-sac, retrotarsal fold. (05 Mar 2000) |
| conjunctival sac | The space bound by the conjunctival membrane between the palpebral and bulbar conjunctiva; into which the lacrimal fluid is secreted; it opens anteriorly between the eyelids. Synonym: saccus conjunctivae. (05 Mar 2000) |
| cul-de-sac | 1. A blind pouch or tubular cavity closed at one end; e.g., diverticulum; caecum. Synonym: rectouterine pouch. Origin: Fr. Bottom of a sack (05 Mar 2000) |
| cul-de-sac smear | A cytologic specimen of material obtained by aspirating the pouch of Douglas from the posterior vaginal fornix and prepared by smearing, centrifuging, or filtering; used principally for ovarian cancer. (05 Mar 2000) |
| 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) |