sinus

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sinus

 [si´nus]
1. a recess, cavity, or channel, such as one in bone or a dilated channel for venous blood.
2. an abnormal channel or fistula, permitting escape of pus.
anal s's furrows, with pouchlike recesses at the distal end, separating the rectal columns; called also anal crypts.
anterior s's (sinus anterio´res) the anterior air cells that together with the middle and posterior air cells form the ethmoidal sinus.
aortic s's pouchlike dilatations at the root of the aorta, one opposite each semilunar cusp of the aortic valve, from which the coronary arteries originate.
carotid sinus a dilatation of the proximal portion of the internal carotid or distal portion of the common carotid artery, containing in its wall pressoreceptors that are stimulated by changes in blood pressure. See also carotid sinus syndrome.
cavernous sinus an irregularly shaped venous channel between the layers of dura mater of the brain, one on either side of the body of the sphenoid bone and communicating across the midline. Several cranial nerves course through this sinus.
cerebral sinus one of the ventricles of the brain.
cervical sinus a temporary depression in the neck of the embryo containing the branchial arches.
circular sinus the venous channel encircling the pituitary gland, formed by the two cavernous sinuses and the anterior and posterior intercavernous sinuses.
coccygeal sinus a sinus or fistula just over or close to the tip of the coccyx.
coronary sinus the dilated terminal portion of the great cardiac vein, receiving blood from other veins draining the heart muscle and emptying into the right atrium.
dermal sinus a congenital sinus tract extending from the surface of the body, between the bodies of two adjacent lumbar vertebrae, to the spinal canal.
ethmoid s's (ethmoidal s's) ethmoid cells.
frontal sinus one of the paired paranasal sinuses in the frontal bone, each communicating with the middle nasal meatus on the same side.
intercavernous s's channels connecting the two cavernous sinuses, one passing anterior and the other posterior to the stalk of the pituitary gland.
lymphatic s's irregular, tortuous spaces within lymphoid tissues through which lymph flows.
maxillary sinus one of the paired paranasal sinuses in the body of the maxilla on either side, opening into the middle nasal meatus on the same side.
occipital sinus a venous sinus between the layers of dura mater, passing upward along the midline of the cerebellum.
paranasal s's the eight cavities in the skull that are connected with the nasal cavity (see also Plates). They are arranged in four pairs, each of which has one member on the left and one on the right. The pairs are the maxillary sinuses in the maxillae; the frontal sinuses in the frontal bone; the sphenoid sinuses in the sphenoid bone behind the nasal cavity; and the ethmoid cells (ethmoid sinuses) in the ethmoid bone behind and below the frontal sinuses. The functions of the sinuses are not certain. They are believed to help the nose in circulating, warming, and moistening the air as it is inhaled, thereby lessening the shock of cold, dry air to the lungs. They also are thought to have a minor role as resonating chambers for the voice.
Sinus paranasal (Paranasal sinuses). From Dorland's, 2000.
petrosal sinus, inferior a venous channel arising from the cavernous sinus and draining into the internal jugular vein.
petrosal sinus, superior one arising from the cavernous sinus and draining into the transverse sinus of the dura mater.
pilonidal sinus pilonidal cyst.
prostatic sinus the posterolateral recess between the seminal colliculus and the wall of the urethra, where the prostatic ductules empty into the urethra.
s's of pulmonary trunk spaces between the wall of the pulmonary trunk and cusps of the pulmonary valve at its opening from the right ventricle.
renal sinus a recess in the substance of the kidney, occupied by the renal pelvis, calices, vessels, nerves, and fat.
sagittal sinus, inferior a small venous sinus of the dura mater, opening into the straight sinus.
sagittal sinus, superior a venous sinus of the dura mater that ends in the confluence of sinuses.
sigmoid sinus a venous sinus of the dura mater on either side, continuous with the straight sinus and draining into the internal jugular vein of the same side.
sphenoid sinus (sphenoidal sinus) one of the paired paranasal sinuses in the body of the sphenoid bone, opening into the superior nasal meatus on the same side.
sphenoparietal sinus one of the venous sinuses of the dura mater, emptying into the cavernous sinus.
s's of spleen dilated venous sinuses found in the splenic pulp; they are not lined by ordinary endothelial cells.
straight sinus a venous sinus of the dura mater formed by junction of the great cerebral vein and inferior sagittal sinus, and ending in the confluence of sinuses.
tarsal sinus a space between the calcaneus and talus.
tentorial sinus straight sinus.
transverse sinus of dura mater a large venous sinus on either side of the brain.
transverse sinus of pericardium a passage within the pericardial sac, behind the aorta and pulmonary trunk and in front of the left atrium and superior vena cava.
tympanic sinus a deep recess on the medial wall of the middle ear.
urogenital sinus an elongated sac that is formed by division of the cloaca in the early embryo, which ultimately forms most of the vestibule, urethra, and vagina in the female, and some of the urethra in the male.
uterine s's venous channels in the wall of the uterus in pregnancy.
uteroplacental s's blood spaces between the placenta and uterine sinuses.
sinus of venae cavae the posterior portion of the right atrium into which the inferior and the superior vena cava open; called also sinus venosus.
sinus veno´sus (venous sinus)
2. the common venous receptacle in the early embryo attached to the posterior wall of the primitive atrium.
venous s's of dura mater large channels for venous blood forming an anastomosing system between the layers of the dura mater of the brain, receiving blood from the brain and draining into the veins of the scalp or deep veins at the base of the skull.
venous sinus of sclera a circular channel at the junction of the sclera and cornea, into which aqueous humor filters from the anterior chamber of the eye. Called also Schlemm's canal.

si·nus

, pl.

si·nus

,

si·nus·es

(sī'nŭs, -ĕz), The plural of this word is sinus, not sini.
1. A channel for the passage of blood or lymph, without the coats of an ordinary vessel; for example, blood passages in the gravid uterus or those in the cerebral meninges.
2. A cavity or hollow space in bone or other tissue.
3. A dilation in a blood vessel.
4. A fistula or tract leading to a suppurating cavity.
[L. sinus, cavity, channel, hollow]

sinus

/si·nus/ (si´nus) pl. si´nus, sinuses   [L.]
1. a recess, cavity, or channel, as (a) one in bone or (b) a dilated channel for venous blood.
2. an abnormal channel or fistula permitting escape of pus.si´nusal

air sinus  an air-containing space within a bone.
anal sinuses  furrows, with pouchlike openings at the distal end, separating the rectal columns.
aortic sinus  a dilatation between the aortic wall and each of the semilunar cusps of the aortic valve; from two of these sinuses the coronary arteries originate.
branchial sinus  an abnormal cavity or space opening externally on the inferior third of the neck; usually a result of persistence of the second pharyngeal groove and cervical sinus.
carotid sinus  a dilatation of the proximal portion of the internal carotid or distal portion of the common carotid artery, containing in its wall pressoreceptors which are stimulated by changes in blood pressure.
Enlarge picture
Carotid sinus (sinus caroticus) and carotid arteries in a deep dissection of the right side of the neck.
cavernous sinus  either of two irregularly shaped sinuses of the dura mater, located at either side of the body of the sphenoid bone and communicating across the midline; it contains the internal carotid artery and abducent nerve.
cervical sinus  a temporary depression caudal to the second pharyngeal arch, containing the succeeding pharyngeal arches; it is overgrown by the second pharyngeal arch and closes off as the cervical vesicle.
circular sinus  the venous channel encircling the hypophysis, formed by the two cavernous sinuses and the anterior and posterior intercavernous sinuses.
coccygeal sinus  a sinus or fistula just over or close to the tip of the coccyx.
coronary sinus  the terminal portion of the great cardiac vein, lying in the coronary sulcus between the left atrium and ventricle, and emptying into the right atrium.
cortical sinuses  lymph sinuses in the cortex of a lymph node, which arise from the marginal sinuses and continue into the medullary sinuses.
dermal sinus  a congenital sinus tract extending from the surface of the body, between the bodies of two adjacent lumbar vertebrae, to the spinal canal.
dural sinuses  large venous channels forming an anastomosing system between the layers of the dura mater, draining the cerebral veins and some diploic and meningeal veins into the veins of the neck.
sinus of epididymis  a long, slitlike serous pocket between the upper part of the testis and the overlying epididymis.
ethmoid sinuses , ethmoidal sinuses see under cell.
frontal sinus  one of the paired paranasal sinuses in the frontal bone, each communicating with the middle meatus of the ipsilateral nasal cavity.
intercavernous sinuses  two sinuses of the dura mater connecting the two cavernous sinuses, one passing anterior and the other posterior to the infundibulum of the hypophysis.
lacteal sinuses , lactiferous sinuses enlargements of the lactiferous ducts just before they open on the mammary papilla.
lymphatic sinuses  irregular, tortuous spaces within lymphoid tissue (nodes) through which lymph passes, to enter efferent lymphatic vessels.
marginal sinuses 
1. see under lake.
2. bowl-shaped lymph sinuses separating the capsule from the cortical parenchyma, and from which lymph flows into the cortical sinuses.
maxillary sinus  one of the paired paranasal sinuses in the body of the maxilla on either side, and opening into the middle meatus of the ipsilateral nasal cavity.
medullary sinuses  lymph sinuses in the medulla of a lymph node, which divide the lymphoid tissue into a number of medullary cords.
occipital sinus  one of the sinuses of the dura mater, passing upward along the midline of the cerebellum.
oral sinus  stomodeum.
paranasal sinuses  mucosa-lined air cavities in bones of the skull, communicating with the nasal cavity and including ethmoidal, frontal, maxillary, and sphenoidal sinuses.
Enlarge picture
Paranasal sinuses (sinus paranasales).
petrosal sinus  either of two sinuses of the dura mater, arising from the cavernous sinus and draining into the internal jugular vein (inferior petrosal s.) or into the transverse sinus (superior petrosal s.).
pilonidal sinus  a suppurating sinus containing hair, occurring chiefly in the coccygeal region.
prostatic sinus  the posterolateral recess between the seminal colliculus and the wall of the urethra.
sinus of pulmonary trunk  a slight dilatation between the wall of the pulmonary trunk and each of the semilunar cusps of the pulmonary trunk valve.
renal sinus  a recess in the substance of the kidney, occupied by the renal pelvis, calices, vessels, nerves, and fat.
sagittal sinus, inferior  a small venous sinus of the dura mater, opening into the straight sinus.
sagittal sinus, superior  a venous sinus of the dura mater which ends in the confluence of sinuses.
sigmoid sinus  a venous sinus of the dura mater on either side, continuous with the transverse sinus and draining into the internal jugular vein of the same side.
sphenoid sinus , sphenoidal sinus one of the paired paranasal sinuses in the body of the sphenoid bone and opening into the highest meatus of the ipsilateral nasal cavity.
sphenoparietal sinus  either of two sinuses of the dura mater, draining into the anterior part of the cavernous sinus.
sinus of spleen  a dilated venous sinus in the substance of the spleen.
straight sinus  one of the sinuses of the dura mater formed by junction of the great cerebral vein and inferior sagittal sinus, commonly ending in the confluence of the sinuses.
tarsal sinus  a space between the calcaneus and talus.
tentorial sinus  straight s.
terminal sinus  a vein that encircles the vascular area in the blastoderm.
transverse sinus 
1. either of two large sinuses of the dura mater.
2. a passage behind the aorta and pulmonary trunk and in front of the atria.
tympanic sinus  a deep recess in the posterior part of the tympanic cavity.
urogenital sinus  an elongated sac formed by division of the cloaca in the early embryo, forming most of the bladder, the female vestibule, urethra, and vagina, and most of the male urethra.
uterine sinuses  venous channels in the wall of the uterus in pregnancy.
sinus of venae cavae  the portion of the right atrium into which the inferior and the superior venae cavae open.
sinus veno´sus 
1. the common venous receptacle in the embryonic midheart, attached to the posterior wall of the primordial atrium.
2. venous s. (1).
venous sinus 
1. a large vein or channel for the circulation of venous blood.
2. s. venosus (1).
venous sinuses of dura mater  large channels for venous blood forming an anastomosing system between the layers of the dura mater of the brain, receiving blood from the brain and draining into the veins of the scalp or deep veins at the base of the skull.
venous sinus of sclera  a branching, circumferential vessel in the internal scleral sulcus, a major component of the drainage pathway for aqueous humor.

sinus

(sī′nəs)
n.
1. A depression or cavity formed by a bending or curving.
2. Anatomy
a. A dilated channel or receptacle containing chiefly venous blood.
b. Any of various air-filled cavities in the bones of the skull, especially one communicating with the nostrils.
3. Medicine A fistula leading from a pus-filled cavity.
4. Botany A recess or indentation between two lobes or segments, as of a leaf.

sinus

[sī′nəs]
Etymology: L, hollow
a cavity or channel, such as a cavity within a bone, a dilated channel for venous blood, or one permitting the escape of purulent material.

sinus

A hollow cavity, sac, pouch or opening, such as urogenital sinus; a cavity or hollow space in a tissue or organ (e.g., bone).

si·nus

, pl. sinus, sinuses (sī'nŭs, -ĕz)
1. A channel for the passage of blood or lymph, without the coats of an ordinary vessel, e.g., blood passages in the gravid uterus or those in the cerebral meninges.
2. A cavity or hollow space in bone or other tissue.
3. A dilation in a blood vessel.
4. A fistula or tract leading to a suppurating cavity.
[L. sinus, cavity, channel, hollow]

sinus

(si'nus) plural.sinuses, sinus [L., sinus, curve, hollow]
1. A recess.
2. A cavity with a narrow opening.
3. An endothelia-lined, air-filled cavity within a bone. (When nonmedical people speak of 'sinuses', they are generally referring to this type of sinus, specifically, to the paranasal sinuses.)
4. An endothelia-lined channel for venous blood.
5. A channel leading to an abscess.

accessory nasal sinus

Paranasal sinus.

air sinus

Paranasal sinus.

anal sinus

Any of the saclike recesses on the inner lining of the anal canal between the anal columns.

aortic sinus

Inside the aorta, the pouch behind each of the three leaflets of the aortic valve. The right and left coronary arteries each originate from an orifice in an aortic sinus, leaving one aortic sinus (the noncoronary sinus) as a blind pouch. Synonym: sinus of Valsalva

basilar sinus

Transverse sinus (2).

carotid sinus

The small dilation at the base of the internal carotid artery with baroreceptors in its wall. These receptors respond to changes in arterial blood pressure, and their signals are carried to the hindbrain by the glossopharyngeal nerve (CN IX).

sinus cavernosus

Cavernous sinus.

cavernous sinus

A 1 cm wide dural sinus extending 2 cm along the medial wall of the base of the middle cranial fossa. The cavernous sinus empties into (a) the transverse sinus via the superior petrosal sinus, (b) the internal jugular vein via the inferior petrosal sinus, (c) the pterygoid plexus via emissary veins, and (d) the facial vein via the superior ophthalmic vein. The right and left cavernous sinuses are interconnected by the anterior and posterior intercavernous sinuses. Tributaries of the cavernous sinus include the superior ophthalmic, superficial middle cerebral, and inferior cerebral veins and the sphenoparietal sinus.
Synonym: sinus cavernosus

cerebral sinus

Dural sinus.

circular sinus

A set of four interconnected dural sinuses encircling the sella turcica and pituitary gland at the base of the brain. The four sinuses are the right and left cavernous sinuses and the anterior and posterior intercavernous sinuses.

coccygeal sinus

A sinus in the midline of the gluteal cleft just over the coccyx.

confluence of the sinuses

The dilated posterior end of the superior sagittal sinus in the skull. This dilation joins one of the transverse sinuses (usually the right), which drains the blood from the superior sagittal sinus toward the internal jugular vein. The other transverse sinus and the occipital sinus also connect to the confluence of the sinuses.)

coronary sinus

A large vein on the posterior surface of the heart; it runs in the atrioventricular groove between the left atrium and left ventricle. Most of the blood feeding the heart returns to the right atrium via the coronary sinus. Its direct tributaries include the small, middle, and great cardiac veins.

cranial sinus

Any of the large veins between the two layers of the cranial dura mater.

cranial venous sinus

Sinus (3).

dermal sinus

A congenital sinus tract connecting the surface of the body with the spinal canal.

draining sinus

An abnormal passageway leading from inside the body to the outside. This is usually due to an infectious process.

dural sinus

Any of several large endothelia-lined collecting channels into which veins of the brain and inner skull empty and which then empty into the internal jugular vein. These venous sinuses are found between the two layers (periosteal and meningeal) of the dura mater. Their walls have no muscle, and they have no valves to give direction to the blood flow. The venous sinuses in the skull include the superior sagittal, inferior sagittal, straight, transverse, and cavernous sinuses.
Synonym: cerebral sinus; dural venous sinus

dural venous sinus

Dural sinus.

ethmoid sinus

Any of the 3-18 paranasal sinuses on each side of the skull in and adjacent to the ethmoid bone. The ethmoid sinuses can be categorized as anterior, middle, or posterior, with each group usually draining into a different part of the nasal cavity. Ethmoid sinuses have very thin walls and are interconnected via openings in the septa between the sinuses.

frontal sinus

Either of a pair of paranasal sinuses in the frontal bones just above the orbits. These sinuses lie adjacent to each other in the midline, but are usually completely separated by a bony septum. Each frontal sinus drains into the ipsilateral nasal cavity through an opening in the lateral wall along the middle nasal passageway (i.e., middle nasal meatus).

genitourinary sinus

Urogenital sinus.

hair sinus

The sinus formed when hair is embedded in the skin and acts as a foreign body.

inferior longitudinal sinus

Inferior sagittal sinus.

inferior petrosal sinus

A dural sinus that drains the cavernous sinus posteriorly into the superior jugular bulb of the internal jugular vein.

inferior sagittal sinus

An unpaired midline dural sinus running along the lower, free margin of the falx cerebri (over the top of the corpus callosum). It drains blood from veins in the falx and from the medial surfaces of the hemispheres, and it empties, posteriorly, into the straight sinus.

intercavernous sinus

The anterior and the posterior intercavernous sinuses interconnect the right and left cavernous sinuses at the base of the brain. All sinuses are valveless; thus, the cavernous and intercavernous sinuses form a circle -- the circular sinus -- that enwraps the sella turcica.

lactiferous sinus

Immediately inside the tip of the nipple, the dilated end of any of the 15-20 lactiferous ducts, which convey milk from the mammary glands during lactation.

lateral sinus

Either of two large venous sinuses in the inner side of the skull passing near the mastoid antrum and emptying into the jugular vein.

lymph sinus

Endothelia-lined channels through which lymph flows inside lymph nodes. The walls of lymph sinuses are coated with T and B lymphocytes as well as phagocytic cells, all of which filter the passing lymph. Lymphocytes and macrophages move in and out of the lymph through the sinus walls.
Synonym: lymph channel

marginal sinus

1. Considered together, the many dilated veins or venous "lakes" that collect blood in the intervillous space of the placenta; the marginal sinus drains into the uterine veins.
2. A dural sinus along the inside of the rim of the foramen magnum; it drains into the vertebral venous plexus.
3. A blood-filled sinus in the marginal zone of the spleen. In the passage from the red pulp to the white pulp, some arterial blood flows along (and percolates through) the endothelia-lined walls of the marginal sinus before entering the arterial capillary beds of the white pulp.

mastoid sinus

An old term for the mastoid antrum.

maxillary sinus

Either of a pair of paranasal sinuses filling the bodies of the maxillary bones. The maxillary sinuses are large and pyramidal shaped, with average dimensions of 3.5 cm x 2.5 cm x 3.2 cm. The medial floor of the maxillary sinus is immediately above the roots of the first and second upper molars. Each maxillary sinus drains into the ipsilateral nasal cavity through an opening in the lateral wall of the hiatus semilunaris, under the middle nasal concha. Synonym: antrum of Highmore

occipital sinus

A slender dural sinus running in the posterior, i.e., attached, margin of the falx cerebelli. It begins near the foramen magnum, and it ascends along the midline of the occipital bone. The occipital sinus empties into the confluence of the sinuses.
Enlarge picture
PARANASAL SINUS

paranasal sinus

An air cavity in a facial bone, either the frontal, maxillary, sphenoid, or ethmoid bones; most paranasal sinuses occur in pairs. The paranasal sinuses are lined with ciliated epithelium that secretes mucus. The sinuses open into the lateral walls of the nasal cavities via small holes. Healthy paranasal sinuses are radiolucent. Synonym: accessory nasal sinus; air sinus; See: illustration
illustration

pericardial sinus

The oblique or the transverse pericardial sinus, which are spaces between the visceral and parietal layers of the serous pericardium. The oblique sinus runs along the posterior surface of the left atrium between the orifices of the right and the left pulmonary veins. The transverse sinus runs along the posterior surface of the base of the heart between the outflow vessels (the aorta and the pulmonary trunk) in front and the inflow vessels (the pulmonary veins) behind.

petrosal sinus

The superior or the inferior petrosal sinus.

pilonidal sinus

Pilonidal fistula.

pleural sinus

Any of the spaces in the pleural sac along the lower and inferior portions of the lung that the lung does not occupy.

sinus pocularis

A lacuna in the prostatic part of the urethra. Synonym: sinus prostaticus

sinus prostaticus

Sinus pocularis.

pulmonary sinus

Either of the pouches within the pulmonic trunk behind each of the three leaflets of the pulmonic valve.

sinus rectus

Straight sinus.

renal sinus

The indentation on the medial side of each kidney into which the hilum leads; the renal sinus is largely filled by the renal pelvis.

rhomboid sinus

The fourth cranial ventricle.

sagittal sinus

The superior or the inferior sagittal sinus.

sigmoid sinus

The continuation of the transverse sinus downward along the wall of the posterior cranial fossa to the jugular canal; there, the sigmoid sinus becomes the superior jugular bulb, the origin of the internal jugular vein.

sphenoid sinus

Either of a pair of paranasal sinuses in the sphenoid bone just above and behind the nasal cavity. The sphenoid sinuses are located adjacent to the optic chiasm, the pituitary gland, and the internal carotid arteries. Each sphenoid sinus drains through an opening in the sphenoethmoidal recess at the very top of the ipsilateral nasal cavity.

sphenoparietal sinus

A venous sinus uniting the cavernous sinus and a meningeal vein.

sinus of spleen

A large-capacity venous channel in the spleen.

straight sinus

An unpaired midline dural sinus where the falx cerebri and the tentorium cerebelli meet. The straight sinus is the posterior continuation of the inferior sagittal sinus. The straight sinus empties into the transverse sinus contralateral to the one joined by the superior sagittal sinus; nonetheless, the straight sinus often communicates, if only through a small channel, with the confluence of the sinuses.
Synonym: sinus rectus

superior petrosal sinus

A slender dural sinus that drains the cavernous sinus posteriorly into the transverse sinus.

superior sagittal sinus

A long unpaired midline channel through the superior margin of the falx cerebri. It begins in the front near the crista galli of the ethmoid bone, and it extends along the entire inner roof of the skull to the internal occipital protuberance in the back. Its posterior end, called the confluence of the sinuses, is dilated and usually joins the right transverse sinus; however, the other transverse sinus and the occipital sinus also communicate with the confluence of the sinuses. Tributaries of the superior sagittal sinus include ascending frontal cerebral veins, superior cerebral veins, diploic veins draining the skull bones, and a number of irregularly shaped venous lacunae. Numerous arachnoid granulations (sites of the return of water and filtrate from the cerebrospinal fluid) protrude into the superior sagittal sinus.

tarsal sinus

Sinus tarsi.

sinus tarsi

A space between the top of the calcaneus bone and the bottom of the tarsal bone.
Synonym: tarsal sinus

tentorial sinus

See: sinus rectus

terminal sinus

A vein encircling the vascular area of the blastoderm.

transverse sinus

A dural sinus in the lateral edge of the tentorium cerebelli along each lateral upper border of the posterior cranial fossa. One transverse sinus (usually the right) is a continuation of the superior sagittal sinus; the other transverse sinus (typically the smaller of the two) is the continuation of the inferior sagittal sinus, although both transverse sinuses usually have a connection near their origin, in the region of the confluence of sinuses. The transverse sinuses run anteriorly and turn downward to become the sigmoid sinuses at the front edges of the tentorium cerebelli; at this point, the transverse sinuses are joined by the superior petrosal sinuses. Tributaries of the transverse sinuses include inferior cerebral, inferior cerebellar, and diploic veins.

sinus tympani

A recess in the medial wall of the tympanic cavity beside the promontory and adjacent to the round window. The sinus tympani can be > 3 mm deep.

urogenital sinus

In the embryo, a space behind the urogenital membrane (a surface structure) and separated from the future rectum by the urorectal septum (an internal structure). The urachus and the mesonephric ducts, i.e., the Wolffian ducts, open into the urogenital sinus. The sinus will later give rise to major parts of the urinary bladder, urethra, vagina, and genitourinary tract glands.

uterine sinus

Any of the venous channels in the walls of the uterus during pregnancy.

uteroplacental sinus

Any of the slanting venous channels from the placenta serving to convey the maternal blood from the intervillous lacunae back into the uterine veins.

sinus of Valsalva

Aortic sinus.

sinus of venal canal

The portion of the right atrium of the heart posterior, and to the left of, the crista terminalis. The inferior and superior vena caval veins empty into it.

sinus venosus

In the embryo, the portion of the developing heart tube that leads into the cavities destined to form the atria and ventricles. The major embryonic veins — umbilical, vitelline, and common cardinal — all lead into the sinus venosum. Later, the sinus venosum will become the posterior smooth wall of the right atrium, including the openings from the coronary sinus and the venae cava.

venous sinus

A valveless irregularly shaped venous channel lined by endothelial cells. Large venous sinuses include the coronary sinus of the heart and the dural sinuses inside the skull; small venous sinuses are found inside certain tissues, such as the spleen.

sinus

1. One of the paired mucous membrane-lined air cavities in a bone, specifically the frontal sinuses in the forehead, the maxillary sinuses (antrums) in the cheek bones, the multicelled ethmoidal sinuses on either side of the upper part of the nose and the sphenoidal sinuses in the base of the skull.
2. Any wide blood channel such as the venous sinuses in the MENINGES.
3. Any tract or FISTULA leading from a deep infected area to a surface.

sinus

  1. (in plants) a depression or margin between two lobes of a leaf.
  2. (in animals) a cavity within a bone, such as that in the human facial bone.
  3. (in animals) a large blood-filled cavity such as the HAEMOCOEL of ARTHROPODS or enlarged veins of fish.

Sinus

Air-filled cavities surrounding the eyes and nose are lined with mucus-producing membranes. They cleanse the nose, add resonance to the voice, and partially determine the structure of the face.

sinus

fistula/tract leading from one body cavity to another or from a body cavity to the exterior, e.g. tract connecting an infected area of osteomyelitis to the skin surface

sinus 

A hollow space in bone or other tissue.
cavernous sinus One of the two venous sinuses in the dura mater of the brain extending on each side of the pituitary body, behind the orbit. It receives blood from the superior and the inferior ophthalmic veins and the central retinal veins. The third, fourth, fifth and sixth nerves pass through as well as the internal carotid artery. The cavernous plexus is located within this sinus. See carotid-cavernous fistula.
sinus circularis iridis See Schlemm's canal.
ethmoidal sinus Mucus-lined air cavities within the ethmoid bone, between the nose and the orbit. They drain into the nasal cavity. They contain the anterior and posterior ethmoidal nerves and blood vessels and are filled with air. They are separated from adjacent areas by very thin plates through which infection can pass easily and in particular ethmoiditis, which is the most common cause of orbital cellulitis.
sinus of Maier See lacrimal apparatus.
scleral s . See Schlemm's canal.
sinus venosus sclerae See Schlemm's canal.

si·nus

, pl. sinus, pl. sinuses (sī'nŭs, -ĕz) The plural of this word is sinus, not sini.
1. [TA] Channel for the passage of blood or lymph, without the coats of an ordinary vessel; e.g., blood passages in gravid uterus or those in cerebral meninges.
2. [TA] Cavity or hollow space in bone or other tissue.
3. Fistula or tract leading to a suppurating cavity.
[L. sinus, cavity, channel, hollow]

sinus (sī´nus),

n a cavity, recess, or hollow space.
sinus, alveolar,
n a passage connecting a pathologic cavity in the alveolus with the oral or nasal cavity and penetrating the mucous membrane. See also fistula, alveolar.
sinus balloon,
sinus, carotid,
n the swelling in the artery just before the common carotid artery bifurcates into the internal and external carotid arteries.
sinus, coronary,
n the venous sinus in the groove between the left cardiac auricle and the left ventricle.
sinus(es), ethmoidal
n an air space located within the ethmoid bone, which comprises the floor of the skull and the roof of the nose. There are four ethmoid sinuses: the anterior, middle, and two posterior sinuses. The anterior and middle sinuses drain directly into the middle meatus (opening) of the nose. The posterior sinuses drain into the superior meatus of the nose.
sinus(es), frontal,
n an air space located within the frontal bone of the forehead.
sinus(es), maxillary (antrum of Highmore, maxillary antrum),
n a large pyramidal cavity within the body of the maxilla. Its walls are thin and correspond to the orbital, nasal anterior, and infratemporal surfaces of the body of the maxilla. On dental radiographs the floor of the sinus is often observed approximating the root apices of the teeth and is seen to extend from the canine or premolar region posteriorly to the molar or tuberosity region.
sinus(es), paranasal,
n the paired air cavities in various bones around the nose, including the maxillary sinus within the maxilla, the sphenoid sinus in the sphenoid bone, the ethmoid sinuses in the ethmoid bone, and the frontal sinus in the frontal bone.
sinus(es), sphenoid
n an air space located within the wing-like sphenoid bone, located at the base of the skull. These sinuses are variable in shape and size, and are rarely symmetrical because of lateral displacement of the septum.
sinus tract,
sinus pneumatization
n an enlargement of the maxillary sinus, usually as part of the aging process and as a result of the loss of maxillary teeth.

sinus

1. a recess, cavity, or channel, as (a) one in bone or (b) a dilated, valveless channel for venous blood.
2. an abnormal channel or fistula, permitting escape of pus. In common, unqualified usage, the word sinus refers to any of the cavities in the skull that are connected with the nasal cavity—the paranasal sinuses.

anal s's
furrows, with pouchlike recesses at their distal ends, separating the rectal columns; called also anal crypts.
basilar sinus
a dural venous sinus which runs on the floor of the cranial cavity and out through the foramen magnum.
cavernous sinus
an irregularly shaped venous channel between the layers of dura mater of the brain, one on either side of the body of the sphenoid bone and communicating across the midline. Several cranial nerves and, when present, the rete mirabile, course through this sinus.
cavernous sinus syndrome
lesions of the cavernous syndrome, caused by neoplasia or infectious agents, result in a dilated pupil and paralysis of the globe; vision is usually spared.
cerebral sinus
one of the ventricles of the brain.
cervical sinus
a temporary depression in the neck of the embryo containing the branchial arches.
circular sinus
the venous channel encircling the pituitary gland, formed by the two cavernous sinuses and the anterior and posterior intercavernous sinuses.
conchal sinus
cavity of the conchal bone.
coronary sinus
the terminal portion of the great cardiac vein, which lies in the cardiac sulcus between the left atrium and ventricle, and empties into the right atrium.
dermoid sinus, dermal sinus
see dermoid sinus.
dorsal sagittal sinus
a large dural venous sinus located within the falx cerebri.
dura mater venous sinus
large channels for venous blood forming an anastomosing system between the layers of the dura mater of the brain.
ethmoidal sinus
that paranasal sinus consisting of the ethmoidal cells collectively, and communicating with the nasal meatuses.
facial sinus
see malar abscess.
frontal sinus
one of the paired paranasal sinuses in the frontal bone, each communicating with the middle meatus of the ipsilateral nasal cavity.
hair sinus
see sinus hair.
infraorbital sinus
an air-filled recess in the head of birds which lies lateral to the nasal cavity into which it opens.
intercavernous sinus
channels connecting the two cavernous sinuses, one passing anterior and the other posterior to the stalk of the pituitary gland.
interdigitalis sinus
the cutaneous pouch, which lies between the claws of sheep and some other ruminants and whose wall contains apocrine glands, and whose duct surfaces on the skin just above the coronets; it serves as a trail gland.
lymphatic sinus
irregular, tortuous spaces within lymphoid tissues through which lymph flows.
maxillary sinus
one of the paired paranasal sinuses in the body of the maxilla on either side, opening into the middle meatus of the ipsilateral nasal cavity. In the horse it is divided into two compartments that communicate independently with the nasal chambers. All other sinuses of the horse communicate with the nasal chambers via the caudal maxillary sinus.
nasal sinus
see paranasal sinuses (below).
sinus nerve
a branch of the glossopharyngeal nerve; carries the afferent fibers of the stretch receptors in the wall of the carotid sinus.
sinus node
see sinoatrial node.
occipital sinus
a venous sinus between the layers of dura mater, passing along the midline of the cerebellum.
paranasal s's
mucosa-lined air cavities in bones of the skull, communicating with the nasal cavity and including ethmoidal, frontal, maxillary and sphenoidal sinuses.
petrosal sinus (inferior)
a venous channel arising from the cavernous sinus and draining into the internal jugular vein.
petrosal sinus (superior)
one arising from the cavernous sinus and draining into the transverse sinus of the dura mater.
prostatic sinus
the dorsolateral recess between the seminal colliculus and the wall of the urethra.
pulmonary trunk sinus
spaces between the wall of the pulmonary trunk and cusps of the pulmonary valve at its opening from the right ventricle.
red pulp sinus
vascular storage in the spleen into which capillaries empty.
sinus reflex arc
afferent fibers are in the sinus nerve; these connect with the cardioinhibitory and vasomotor centers which control blood pressure and heart rate via sympathetic fibers to blood vessels; provides a route for the sinus reflex which relates pressure in the carotid sinus to the performance of the circulatory system.
renal sinus
a recess in the substance of the kidney, occupied by the renal pelvis, calices, vessels, nerves and fat.
sagittal sinus (inferior)
a small venous sinus of the dura mater of large animals found between the cerebral hemispheres and opening into the straight sinus.
sagittal sinus (superior)
a venous sinus of the dura mater that courses between the cerebral hemispheres and ends in the confluence of sinuses.
scleral venous sinus
sigmoid sinus
a venous sinus of the dura mater on either side, continuous with the straight sinus and draining into the internal jugular vein of the same side.
sphenoidal sinus
one of the paired paranasal sinuses in the body of the sphenoid bone of some species. In the horse it communicates with the nasal cavity via the frontal and caudal maxillary sinuses.
sphenoparietal sinus
one of the venous sinuses of the dura mater, emptying into the cavernous sinus.
splenic sinus
dilated venous channels in the substance of the spleen. See also red pulp sinus (above).
straight sinus
a venous sinus of the dura mater formed by junction of the great cerebral vein and inferior sagittal sinus, and ending in the confluence of sinuses.
tarsal sinus
a space between the calcaneus and talus.
tentorial sinus
straight sinus.
transverse dura mater sinus
a large venous sinus that runs in the attached border of the cerebellar tentorium on either side of the skull.
transverse pericardial sinus
a passage within the pericardial sac, between the aorta and pulmonary trunk cranioventrally, and the left atrium and cranial vena cava dorsally.
tympanic sinus
a deep recess on the medial wall of the middle ear.
urachal sinus
an anomalous closure of the urachal canal in the newborn in which the opening at the umbilicus remains open. The bladder is normal. It is the cause of persistent infection and swelling at the umbilicus in the young animal and may lead to cystitis and pyelonephritis.
urethral s
a small cavity in the glans penis of the horse, above the urethral process; as a recess of the fossa glandis it is usually filled with a small mass (bean) of inspissated smegma.
urogenital sinus
an elongated sac formed by division of the cloaca in the early embryo, which ultimately forms most of the vestibule, urethra and vagina in the female, and some of the urethra in the male.
uterine sinus
venous channels in the wall of the uterus in pregnancy.
uteroplacental sinus
blood spaces between the placenta and uterine sinuses.
venae caval sinus
the posterior portion of the right atrium into which the inferior and the superior vena cava open.
sinus venarum
a chamber which is the greater part of the right atrium into which the great veins discharge.
venous sinus, sinus venosus
1. the common venous receptacle in the heart of the early embryo that receives blood from the umbilical and vitelline veins and from the body via the ducts of Cuvier.
2. sinus of venae cavae.
vertebral sinus
a continuation of part of the common occipital vein in birds; it emerges from the foramen magnum and accompanies the vertebral vein.

Patient discussion about sinus

Q. I have been having chronic pain in sinus area and behind my eyes, been to ENT who states it is not infection? I wake up with the pain and go to sleep in severe pain. Its all day and all night. Dr insists that its migraine related and allergy related. I have chronic postnasal drainage. It started 4 months ago when I moved into our new house. The pain makes me extremely fatigue and dizzy at times. I have been referred to the eye doctor, a headache specialist and an allergy specialist. Just recently I have had a CT scan and an MRI, as well as xrays of my sinus. Nothing other than a deviated septum and possible allergies from an ENT has been diagnosed. In the mean time I am waiting for the days to come when I can get into see these specialist. Anyone out there have any of the same symptoms?? Need help here. Soooooo sick of the pain.

A. i have chronic sinusitis and can really relate to what you describe. learned to live with the pain...but still, i use various ways to reduce inflammation in my sinuses, i heat the place up before going to sleep, try to avoid eating or drinking cold stuff.
another thing i do is i heat water (80c) then add a special oil i bought in a chinese medicine store , about 5 drops, and inhale the fumes. nettle tea can do wonders too.

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