| spiral septum | A septum dividing the embryonic bulbus cordis into pulmonary and aortic outflow tracts from the developing heart; the distal spiral septum is derived from the right and left endocardial cushions and so separates the pulmonary and aortic orifices; the proximal spiral septum is the portion of the septum that is incorporated into the membranous part of the interventricular septum. (05 Mar 2000) |
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| nasal septum | The dividing wall that runs down the middle of the nose so that there are normally two sides to the nose, each ending in a nostril. (12 Dec 1998) |
| depressor muscle of septum | <anatomy> A vertical fasciculus from the orbicularis oris musculus passing upward along the median line of the upper lip, and inserted into the cartilaginous septum of the nose; action, depresses septum; nerve supply, facial. Synonym: musculus depressor septi, depressor muscle of septum. (05 Mar 2000) |
| distal spiral septum | See: spiral septum. (05 Mar 2000) |
| division septum | <cell biology> The cell wall that forms between daughter cells at the end of mitosis in plant cells or just before separation in bacteria. (18 Nov 1997) |
| interalveolar septum | The tissue intervening between two adjacent pulmonary alveoli; it consists of a close-meshed capillary network covered on both surfaces by very thin alveolar epithelial cells, one of the bony partitions between the tooth sockets. Synonym: septum interalveolare, alveolar septum, septal bone. (05 Mar 2000) |
| interatrial septum | The partition separating the upper chambers (the atria) of the heart. (12 Dec 1998) |
| interdental septum | The bony portion separating two adjacent teeth in a dental arch. (05 Mar 2000) |
| interlobular septum | The connective tissue between pulmonary lobules, usually containing a vein and lymphatics; seen radiographically when thickened as a Kerley B line. (05 Mar 2000) |
| intermediate cervical septum | A thin septum composed of glia fibre and leptomeningeal connective tissue in the cervical spinal cord marking the border between the gracile fasciculi and cuneatus of the dorsal funiculus. Synonym: septum cervicale intermedium. (05 Mar 2000) |
| intermuscular septum | <anatomy> A term applied to aponeurotic sheets separating various muscles of the limbs; these are anterior and posterior crural, lateral and medial femoral, lateral and medial humeral. Synonym: septum intermusculare. (05 Mar 2000) |
| interpulmonary septum | <anatomy> The space in the thoracic cavity behind the sternum and in between the two pleural sacs (containing the lungs). (27 Sep 1997) |
| interventricular septum | The stout wall separating the lower chambers (the ventricles) of the heart fromone another. A hole in the interventricular septum is termed a ventricular septal defect (vsd). (12 Dec 1998) |
| orbital septum | A fibrous membrane attached to the margin of the orbit and extending into the lids, containing the orbital fat and constituting in great part the posterior fascia of the orbicularis oculi muscle. Synonym: septum orbitale. (05 Mar 2000) |
| transparent septum | A thin plate of brain tissue, containing nerve cells and numerous nerve fibres, that is stretched like a flat, vertical sheet between the column and body of fornix below, the corpus callosum above and anteriorly; it is usually fused in the median plane with its partner on the opposite side so as to form a thin, median partition between the left and right frontal horn of the lateral ventricles; in less than 10% of humans there is a blind, slitlike, fluid-filled space between the two transparent septa, the cavity of septum pellucidum. The transparent septum is continuous ventralward through the interval between the corpus callosum and the anterior commissure with the precommissural septum and subcallosal gyrus. See: cavity of septum pellucidum, septal area. Synonym: septum pellucidum, septum lucidum. (05 Mar 2000) |