| sinus | <anatomy> A notch, depression or cavity on the surface of an organ. (09 Oct 1997) |
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| sinus alae parvae | A paired dural venous sinus beginning on the parietal bone, running along the sphenoidal ridges and emptying into the cavernous sinus. Synonym: sinus sphenoparietalis, Breschet's sinus, sinus alae parvae. (05 Mar 2000) |
| sinus anales | The grooves between the anal columns. Synonym: Morgagni's sinus. Pockets or crypts in the columnar zone of the anal canal between the anocutaneous line and the anorectal line; the sinuses give the mucosa a scalloped appearance. Synonym: sinus anales, anal crypts, Morgagni's crypts, rectal sinuses. (05 Mar 2000) |
| sinus aortae | The space between the superior aspect of each cusp of the aortic valve and the dilated portion of the wall of the ascending aorta, immediately above each cusp. Synonym: sinus aortae, Petit's sinus, Valsalva's sinus. Arlt's sinus, an inconstant depression on the lower portion of the internal surface of the lacrimal sac. Barber's pilonidal sinus, pilonidal sinus occurring in barbers, usually in the web between the fingers, due to the burying of exogenous hairs by the alternate loosening and tightening of tissues of the hand by the manipulation of scissors. (05 Mar 2000) |
| sinus arrest | <cardiology, physiology> Cessation of sinus activity; the ventricles may continue to beat under ectopic atrial, atrioventricular junctional, or idioventricular control. See: sinus standstill, atrial standstill. (05 Mar 2000) |
| sinus arrhythmia | <cardiology, physiology> An increase in heart rate during inspiration. A normal physiologic response, more pronounced in children. (27 Sep 1997) |
| sinus barotrauma | Sinus troubles, particulaqrly with pain, due to changing atmospheric pressures, as when going up or down in a plane. Also called aerosinusitis or barosinusitis. (12 Dec 1998) |
| sinus bradycardia | <cardiology, physiology> Bradycardia originating in the normal sinus pacemaker. (05 Mar 2000) |
| sinus caroticus | <anatomy> A slight dilation in the carotid artery at its bifurcation into the external and internal carotid arteries, it contains baroreceptors (pressure sensors) that when stimulated, will cause a reflex slowing of the heart, vasodilation and a fall in blood pressure. (27 Sep 1997) |
| sinus cavernosus | <radiology> Contents: III oculomotor n., IV trochlear n., V-1 ophthalmic n. (trigeminal n.), V-2 maxillary n. (trigeminal n.), VI abducens n. Note: mandibular n. (V-3) passes through foramen rotundum (12 Dec 1998) |
| sinus circularis | sinus venosus sclerae |
| sinus coronarius | A short trunk receiving most of the cardiac veins, beginning at the junction of the great cardiac vein and the oblique vein of the left atrium, running in the posterior part of the coronary sulcus and emptying into the right atrium between the inferior vena cava and the atrioventricular orifice. Synonym: sinus coronarius. (05 Mar 2000) |
| sinus durae matris | Endothelium-lined venous channels in the dura mater. Synonym: sinus durae matris, cerebral sinuses, cranial sinuses, sinuses of dura mater, venous sinuses. (05 Mar 2000) |
| sinus epididymidis | A narrow space between the body of the epididymis and the testis. Synonym: sinus epididymidis. Ethmoidal sinuses, ethmoidal air-cells; evaginations of the mucous membrane of the middle and superior meatuses of the nasal cavity into the ethmoidal labyrinth forming multiple small paranasal sinuses; they are subdivided into anterior, middle and posterior ethmoidal sinuses. Synonym: antra ethmoidalia. (05 Mar 2000) |
| sinus ethmoidales | The numerous small air-filled cells of the ethmoidal labyrinth. See: anterior ethmoidal air cells, middle ethmoidal air cells, posterior ethmoidal air cells. Synonym: cellulae ethmoidales, sinus ethmoidales, ethmoidal cells. (05 Mar 2000) |
| Amberg's lateral sinus line | A line dividing the angle formed by the anterior edge of the mastoid process and the temporal line. (05 Mar 2000) |
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| aneurysm of sinus of Valsalva | A congenital thin-walled tubular out pouching usually in the right or non-coronary sinus with an entirely intracardiac course that may rupture into the right or rarely the left heart chambers to form an aortocardiac fistula. (05 Mar 2000) |
| aortic sinus | The space between the superior aspect of each cusp of the aortic valve and the dilated portion of the wall of the ascending aorta, immediately above each cusp. Synonym: sinus aortae, Petit's sinus, Valsalva's sinus. Arlt's sinus, an inconstant depression on the lower portion of the internal surface of the lacrimal sac. Barber's pilonidal sinus, pilonidal sinus occurring in barbers, usually in the web between the fingers, due to the burying of exogenous hairs by the alternate loosening and tightening of tissues of the hand by the manipulation of scissors. (05 Mar 2000) |
| aortic sinus aneurysm | Abnormal dilation of one or more of the three aortic sinuses situated behind the three aortic valve cusps. (05 Mar 2000) |
| apertura sinus frontalis | One of a pair of openings in the floor of the frontal sinuses in the nasal part of the frontal bone, through which the frontal sinuses communicate with the ethmoidal infundibulum via the frontonasal duct. Synonym: apertura sinus frontalis. (05 Mar 2000) |
| apertura sinus sphenoidalis | One of the pair of openings in the body of the sphenoid bone through which the sphenoid sinuses communicate with the sphenoethmoidal recess of the nasal cavity. Synonym: apertura sinus sphenoidalis, sphenoidal sinus aperture. (05 Mar 2000) |
| arrhythmia, sinus | Irregularity of the heart rate related to functioning of the sinoatrial node. (12 Dec 1998) |
| barotrauma, sinus | See: Barosinusitis. (12 Dec 1998) |
| basilar sinus | A venous plexus on the clivus, connected with the cavernous and petrosal sinuses and the internal vertebral (epidural) venous plexus. Synonym: plexus basilaris, basilar sinus. (05 Mar 2000) |
| Breschet's sinus | A paired dural venous sinus beginning on the parietal bone, running along the sphenoidal ridges and emptying into the cavernous sinus. Synonym: sinus sphenoparietalis, Breschet's sinus, sinus alae parvae. (05 Mar 2000) |
| Valsalva's sinus | The space between the superior aspect of each cusp of the aortic valve and the dilated portion of the wall of the ascending aorta, immediately above each cusp. Synonym: sinus aortae, Petit's sinus, Valsalva's sinus. Arlt's sinus, an inconstant depression on the lower portion of the internal surface of the lacrimal sac. Barber's pilonidal sinus, pilonidal sinus occurring in barbers, usually in the web between the fingers, due to the burying of exogenous hairs by the alternate loosening and tightening of tissues of the hand by the manipulation of scissors. (05 Mar 2000) |
| valve of coronary sinus | A delicate fold of endocardium at the opening of the coronary sinus into the right atrium. Synonym: valvula sinus coronarii, coronary valve, thebesian valve. (05 Mar 2000) |
| valvula sinus coronarii | A delicate fold of endocardium at the opening of the coronary sinus into the right atrium. Synonym: valvula sinus coronarii, coronary valve, thebesian valve. (05 Mar 2000) |
| Palfyn's sinus | A space within the crista galli of the ethmoid described as communicating with the ethmoidal and frontal sinus's. Paranasal sinuses, the paired air-filled cavities in the bones of the face lined by mucous membrane continuous with that of the nasal cavity; these sinus's are the frontal, sphenoidal, maxillary, and ethmoidal. Synonym: sinus paranasales. (05 Mar 2000) |
| ramus sinus carotici | <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) |