| hyaloid artery | <anatomy, artery> The terminal branch of the primitive ophthalmic artery, which forms in the embryo an extensive ramification in the primary vitreous and a vascular tunic around the lens; by 81/2 months, these vessels have atrophied almost completely, but a few persistent remnants are evident entoptically as muscae volitantes. Synonym: arteria hyaloidea. (05 Mar 2000) |
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| persistence | 1. The tendency of a cell to continue moving in one direction: an internal bias on the random walk behaviour that cells exhibit in isotropic environments. 2. Of viruses that persist in a cell population, animal, plant or population for long periods often in a nonreplicating form, by such strategies as integration into host DNA, immunological suppression or mutation into forms with slow replication. (18 Nov 1997) |
| hereditary persistence of foetal haemoglobin | <haematology> Hereditary persistence of foetal haemoglobin is a genetic condition where adult types of haemoglobin fail to develop and the types of haemoglobin the individual had as a foetus remains present well past the point when they would normally have stopped being produced. (09 Oct 1997) |
| hyaloid | <anatomy> Resembling glass; vitriform; transparent; hyaline; as, the hyaloid membrane, a very delicate membrane inclosing the vitreous humor of the eye. Origin: Gr. Glassy, transparent; glass + appearance: cf. F. Hyaloide. Source: Websters Dictionary (01 Mar 1998) |
| hyaloid body | The transparent gel that fills the inner portion of the eyeball between the lens (lens, crystalline) and the retina. (12 Dec 1998) |
| hyaloid canal | A minute canal running through the vitreous from the discus nervi optici to the lens, containing in foetal life a prolongation of the central artery of the retina, the hyaloid artery. See: vitreous, hyaloid artery. Synonym: canalis hyaloideus, central canal of the vitreous, Cloquet's canal, Stilling's canal. (05 Mar 2000) |
| hyaloid fossa | A depression on the anterior surface of the vitreous body in which lies the lens. Synonym: fossa hyaloidea, lenticular fossa, patellar fossa of vitreous. (05 Mar 2000) |
| hyaloid membrane | A transparent homogeneous acellular layer between the substantia propria and the endothelial layer of the cornea; considered to be a highly developed basement membrane. Synonym: lamina limitans posterior corneae, membrana vitrea, Descemet's membrane, Duddell's membrane, entocornea, hyaloid membrane, lamina elastica posterior, limiting layers of cornea, membrana hyaloidea, posterior elastic layer, tunica vitrea, vitreous membrane. (05 Mar 2000) |
| anastomotic branch of middle meningeal artery to lacrimal artery | <anatomy, artery> A branch of the middle meningeal artery arising in the cranial cavity which runs anteriorly through the superior orbital fissure to anastomose with the lacrimal artery. See: orbital branch of middle meningeal artery. Synonym: ramus anastomoticus arteriae meningeae mediae cum lacrimali. (05 Mar 2000) |
| Abbott's artery | <anatomy, artery> An anomalous artery arising from the posteromedial proximal descending aorta, important during coarctation repair. (05 Mar 2000) |
| aberrant artery | Artery having an unusual origin or course. (05 Mar 2000) |
| aberrant obturator artery | See: pubic branch of inferior epigastric artery. (05 Mar 2000) |
| accessory meningeal branch of middle meningeal artery | <anatomy, artery> A branch of either the middle meningeal or maxillary artery in the infratemporal fossa and passing superiorly through the foramen ovale to supply the trigeminal ganglion, dura mater and inner table of bone. Synonym: ramus meningeus accessorius arteriae meningeae mediae. (05 Mar 2000) |
| accessory obturator artery | <anatomy, artery> Term applied to the anastomosis of pubic branch of the inferior epigastric artery with the pubic branch of the obturator artery when it contributes a significant supply through the obturator canal. Synonym: arteria obturatoria accessoria, ramus obturatorius arteriae epigastricae inferioris. (05 Mar 2000) |
| acetabular artery | An arterial branch that supplies the acetabulum; two arteries, the obturator and the medial femoral circumflex, have such branches. Synonym: ramus acetabularis, acetabular artery, arteria acetabuli. (05 Mar 2000) |