| 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) |
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| 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) |
| lacunar | Relating to a lacuna. (05 Mar 2000) |
| lacunar abscess | An abscess involving the urethral lacunae. (05 Mar 2000) |
| lacunar amnesia | Amnesia in reference to isolated events. (05 Mar 2000) |
| lacunar ligament | <anatomy> A curved fibrous band that passes horizontally backward from the medial end of the inguinal ligament to the pectineal line; it forms the medial boundary of the femoral ring. See: aponeurosis of external abdominal oblique muscle. Synonym: ligamentum lacunare, Gimbernat's ligament. (05 Mar 2000) |
| lacunar skull | <radiology> Also known as: craniolacunia, mesenchymal dysplasia, may appear normal after several yrs associated with: Chiari malformation (almost always !), myelomeningocele, encephalocele in contrast, increased intracranial pressure has: beaten-silver appearance, closed sutures, with or without abnormal skull size (Lueckenschaedel) (12 Dec 1998) |
| lacunar state | The presence of lacunes in the brain. One of the major factors underlying cerebrovascular disease; high correlation with hypertension and atherosclerosis. Symptomatic forms include pure motor hemiplegia and pure hemisensory syndrome; multiple lacunar infarcts are the most common cause of pseudobulbar palsy. (05 Mar 2000) |
| lacunar tonsillitis | Inflammation of the mucous membrane lining the tonsillar crypts. (05 Mar 2000) |
| anterior tibial node | A small inconstant lymph node in front of the interosseous membrane along the upper part of the anterior tibial vessels. Synonym: nodus tibialis anterior, anterior tibial node. (05 Mar 2000) |
| artery to atrioventricular node | The atrioventricular branches or the nodal branches, the small arteries supplying the atrioventricular node; they usually arise from the right coronary artery where it starts to descend the posterior interventricular sulcus. Synonym: ramus nodi atrioventricularis, atrioventricular nodal branch, branch to atrioventricular node. (05 Mar 2000) |
| artery to the sinuatrial node | Ascending atrial branch, usually (55%) arising from the anterior stem of the right coronary artery (but 35-45% arising from the circumflex branch of the left coronary artery), which runs around the base of the superior vena cava to reach the sinuatrial node. Synonym: ramus nodi sinuatrialis arteriae coronaria dextra, branch to sinuatrial node, sinuatrial nodal branch of right coronary artery, sinuatrial node artery. (05 Mar 2000) |