| lymph node | <anatomy> Small bean-shaped organ made up of a loose meshwork of reticular tissue in which are enmeshed large numbers of lymphocytes, macrophages and accessory cells located along the lymphatic system. Recirculating lymphocytes leave the blood through the specialised high endothelial venules of the lymph node and pass through the node before being returned to the blood through the lymphatic system. Because the lymph nodes act as drainage points for tissue fluids, they are also regions in which foreign antigens present in the tissue fluid are most likely to begin to elicit an immune response. Nodes filter out bacteria or cancer cells that may travel through the lymphatic system. Synonym: lymph glands. (14 Oct 1997) |
|---|---|
| lymph node excision | Surgical excision of one or more lymph nodes. Its most common use is in cancer surgery. (12 Dec 1998) |
| lymph node of azygos arch | A lymph node of the posterior mediastinal group located adjacent to the arch of the azygos vein. Synonym: nodus lymphaticus arcus venae azygos. (05 Mar 2000) |
| lymph node of ligamentum arteriosum | A lymph node of the anterior mediastinal group located adjacent to the ligamentum arteriosum. Synonym: nodus ligamenti arteriosi, lymph node of ligamentum arteriosum. (05 Mar 2000) |
| lymph node permeability factor | A substance, released by lymphocytes when stimulated or damaged, that increases capillary permeability and the accumulation of mononuclear cells. (05 Mar 2000) |
| anterior condyloid foramen | The canal through which the hypoglossal nerve emerges from the skull. Synonym: canalis hypoglossalis, anterior condyloid canal of occipital bone, anterior condyloid foramen. (05 Mar 2000) |
| anterior palatine foramen | An opening in the posterolateral corner of the hard palate opposite the last molar tooth, marking the lower end of the pterygopalatine canal. Synonym: foramen palatinum majus, anterior palatine foramen. (05 Mar 2000) |
| aortic foramen | The opening in the diaphragm bounded by the two crura, the vertebral column, and the median arcuate ligament, through which pass the aorta and thoracic duct. Synonym: hiatus aorticus, aortic foramen, aortic opening. (05 Mar 2000) |
| apical dental foramen | The opening at the apex of the root of a tooth that gives passage to the nerve and blood vessels. Synonym: foramen apicis dentis, apical dental foramen, root foramen. (05 Mar 2000) |
| apical foramen of tooth | The opening at the apex of the root of a tooth that gives passage to the nerve and blood vessels. Synonym: foramen apicis dentis, apical dental foramen, root foramen. (05 Mar 2000) |
| arachnoid foramen | The large midline opening in the posterior inferior part of the roof of the fourth ventricle, connecting the ventricle with the cerebellomedullary cistern. Synonym: apertura mediana ventriculi quarti, arachnoid foramen, Magendie's foramen, median aperture of the fourth ventricle. (05 Mar 2000) |
| Bichat's foramen | <anatomy, vein> An expansion of the subarachnoid space extending forward between the corpus callosum and the thalamus; it encloses the internal cerebral veins which caudally join to form the vena magna cerebri (Galen's vein). Synonym: ambient cistern, Bichat's canal, Bichat's foramen, cistern of great vein of cerebrum, cisterna ambiens, cisterna superioris, cisterna venae magnae cerebri, superior cistern. (05 Mar 2000) |
| blind foramen of frontal bone | <anatomy> Blind or caecal foramen of the frontal bone; the blind foramen formed immediately anterior to the crista galli by a notch at the lower end of the frontal crest and its articulation with the ethmoid bone. It is insignificant postnatally, but gives passage to vessels during development. Synonym: foramen caecum ossis frontalis, blind foramen of frontal bone, caecal foramen of frontal bone. (05 Mar 2000) |
| blind foramen of the tongue | <anatomy> A median pit on the dorsum of the posterior part of the tongue, from which the limbs of a V-shaped furrow run forward and outward; it is the site of origin of the thyroid gland and subsequent thyroglossal duct in the embryo. Synonym: foramen caecum linguae, blind foramen of the tongue, caecal foramen of the tongue, Morgagni's foramen, pleuroperitoneal foramen. (05 Mar 2000) |
| Bochdalek's foramen | An opening through the diaphragm, connecting pleural and peritoneal cavities, usually the result of defective development of the pleuroperitoneal membrane in the embryo; if the defect is extensive there may be herniation of digestive organs into the pleural cavity. See: diaphragmatic hernia. Synonym: Bochdalek's foramen. (05 Mar 2000) |