| sinus ethmoidales mediae | The middle group of air cells of the ethmoidal sinus's; each sinus communicates with the middle meatus of the nasal cavity. Synonym: sinus ethmoidales mediae, cellulae mediae, middle cells, middle ethmoidal sinuses. (05 Mar 2000) |
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| sinus ethmoidales posteriores | The posterior group of air cells of the ethmoidal sinus's; each sinus communicates with the superior meatus of the nasal cavity. Synonym: sinus ethmoidales posteriores, cellulae posteriores, posterior cells. (05 Mar 2000) |
| sinus frontalis | One of the paired, but seldom symmetrical, air spaces located between the inner and outer compact layers of the frontal bone. (12 Dec 1998) |
| sinus histiocytosis | A condition marked by the abnormal appearance of histiocytes (macrophages) in the blood. Lipid h., Niemann-Pick disease. Sinus h., a disorder of the lymph nodes in which the distended sinuses are completely or nearly completely, filled by histiocytes, as a result of active multiplication of the littoral cells. H. X, a generic term embracing eosinophilic granuloma, Letterer-Siwe disease and Hand-Schuller-Christian disease and indicating a shared common origin for the three entities. (16 Dec 1997) |
| sinus histiocytosis with massive lymphadenopathy | A chronic disease occurring in children and characterised by massive painless cervical lymphadenopathy due to distension of the lymphatic sinuses by macrophages containing ingested lymphocytes, and by capsular and pericapsular fibrosis. Synonym: Rosai-Dorman disease. (05 Mar 2000) |
| sinus intercavernosi | The anterior and posterior anastomoses between the cavernous sinus's, passing anterior and posterior to the hypophysis and forming, with the cavernous sinuses, the circular sinus. Synonym: sinus intercavernosi, Ridley's sinus. Jugular sinus Sinus jugularis, one of three enlargements of the jugular veins; the external jugular sinus is between the two sets of valves; the internal jugular sinus's are at the origin (superior bulb) and near the termination (inferior bulb). (05 Mar 2000) |
| sinus lactiferi | A circumscribed spindle-shaped dilation of the lactiferous duct just before it enters the nipple. In nursing mothers this dilatation stores a droplet of milk which is expressed by compression as the infant begins to suckle; this is thought to encourage continual suckling while the let-down reflex ensues. Synonym: sinus lactiferi, ampulla lactifera, ampulla of milk duct, lactiferous ampulla. (05 Mar 2000) |
| sinus laryngeus | The recess in each lateral wall of the larynx between the vestibular and vocal folds and into which the layrngeal sacculus opens. Synonym: ventriculus laryngis, laryngeal sinus, Morgagni's sinus, Morgagni's ventricle, sinus laryngeus. (05 Mar 2000) |
| sinus lienis | An elongated venous channel, 12 to 40 um wide, lined by rod-shaped cells. Synonym: sinus lienis. Straight sinus, an unpaired dural venous sinus in the posterior part of the falx cerebri where it is attached to the tentorium cerebelli; it is formed anteriorly by the merging of the great cerebral vein with the inferior sagittal sinus, and passes horizontally and posteriorly to the confluence of sinuses. Synonym: sinus rectus, tentorial sinus. (05 Mar 2000) |
| sinus maxillaris | A air filled cavity within the maxilla (bone that forms the face and upper jaw). The maxillary sinus is located just below the bony prominence of the cheek (27 Sep 1997) |
| sinus nerve of Hering | <anatomy, nerve> A branch of the glossopharyngeal nerve that innervates the baroreceptors in the wall of the carotid sinus and the chemoreceptors in the carotid body. Synonym: ramus sinus carotici, carotid sinus branch, Hering's sinus nerve, intercarotid nerve, nerve to carotid sinus, sinus nerve of Hering. (05 Mar 2000) |
| sinus node | sinoatrial node |
| sinus node artery | <anatomy, artery> A branch usually of the right coronary artery that supplies the sinuatrial node. Synonym: sinus node artery. (05 Mar 2000) |
| sinus obliquus pericardii | The recess in the pericardial cavity posterior to the base of the heart bounded laterally by the pericardial reflections on the pulmonary veins and inferior vena cava, and posteriorly by the pericardium overlying the anterior aspect of the oesophagus. Synonym: sinus obliquus pericardii, oblique sinus of pericardium. (05 Mar 2000) |
| sinus occipitalis | An unpaired dural venous sinus commencing at the confluence of the sinuses and passing downward in the base of the falx cerebelli to the foramen magnum. Synonym: sinus occipitalis. (05 Mar 2000) |