| medullary substance | The lipid material present in the myelin sheath of nerve fibres. Synonym: Schwann's white substance. (05 Mar 2000) |
|---|---|
| medullary teniae | Slender fascicles of fibres extending transversally below the ependymal floor of the ventricle from the median sulcus to enter the inferior cerebellar peduncle. They arise from the arcuate nuclei on the ventral surface of the medullary pyramid. Synonym: striae medullares ventriculi quarti, acoustic striae, auditory striae, Bergmann's cords, medullary teniae, teniae acusticae. (05 Mar 2000) |
| medullary tube | <embryology> The progenitor of the central nervous system. See: neural plate, neurulation. (18 Nov 1997) |
| posterior medullary velum | A thin sheet of white matter, hidden by the cerebellar tonsil, attached along the peduncle of the flocculus and, at and near the midline, to the nodulus of the vermis; it is continuous caudally with the epithelial lamina and choroid plexus of the fourth ventricle. Synonym: velum medullare inferius, posterior medullary velum, Tarin's valve, valvula semilunaris tarini, velum semilunare, velum tarini. (05 Mar 2000) |
| neoplasms, ductal, lobular, and medullary | Neoplasms, usually carcinoma, located within the centre of an organ or within small lobes, and in the case of the breast, intraductally. The emphasis of the name is on the location of the neoplastic tissue rather than on its histological type. most cancers of this type are located in the breast. (12 Dec 1998) |
| superior medullary velum | The thin layer of white matter stretching between the two superior cerebellar peduncles, forming the roof of the superior recess of the fourth ventricle. Synonym: velum medullare superius, anterior medullary velum, Vieussens' valve. (05 Mar 2000) |
| inferior medullary velum | A thin sheet of white matter, hidden by the cerebellar tonsil, attached along the peduncle of the flocculus and, at and near the midline, to the nodulus of the vermis; it is continuous caudally with the epithelial lamina and choroid plexus of the fourth ventricle. Synonym: velum medullare inferius, posterior medullary velum, Tarin's valve, valvula semilunaris tarini, velum semilunare, velum tarini. (05 Mar 2000) |
| internal medullary lamina | See: medullary laminae of thalamus. (05 Mar 2000) |
| lateral medullary lamina of corpus striatum | A thin, sharply defined layer of fibres separating the putamen from the globus pallidus. Synonym: lamina medullaris lateralis corporis striati. (05 Mar 2000) |
| lateral medullary syndrome | <syndrome> A syndrome due usually to thrombosis, characterised by dysarthria, dysphagia, staggering gait, and vertigo, and marked by hypotonia, incoordination of voluntary movement, nystagmus, Horner's syndrome on the ipsilateral side, and loss of pain and temperature senses on the side of the body opposite to the lesion. Synonym: lateral medullary syndrome, Wallenberg's syndrome. (05 Mar 2000) |
| frenulum of superior medullary velum | A band passing from the longitudinal groove between the quadrigeminal bodies on to the superior medullary velum. Synonym: frenulum veli medullaris superioris, cerebellar frenulum, frenulum cerebelli. (05 Mar 2000) |
| A layer | <molecular biology> Right handed double helical DNA with approximately 11 residues per turn. Planes of base pairs in the helix are tilted 20 deg away from perpendicular to the axis of the helix. Formed from B DNA by dehydration. (18 Nov 1997) |
| ameloblastic layer | The internal layer of the enamel organ. Synonym: enamel layer. (05 Mar 2000) |
| anterior elastic layer | A transparent homogeneous acellular layer, 6 to 9 um thick, lying between the basal lamina of the outer layer of stratified epithelium and the substantia propria of the cornea; considered to be a basement membrane. Synonym: lamina limitans anterior corneae, anterior elastic layer, Bowman's membrane, lamina elastica anterior, limiting layers of cornea. (05 Mar 2000) |
| anterior layer of rectus abdominis sheath | The portion of the rectus sheath that lies anterior to the muscle, consisting in its upper two-thirds of contributions from the aponeuroses of the external and internal oblique muscles, and in its lower third (below the arcuralt line) of contributions from the aponeuroses of all three muscles of the anterolateral abdominal wall. Synonym: lamina anterior vaginae musculi recti abdominis. (05 Mar 2000) |