sinus

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.

3. paranasal sinus.

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)

1. see venous sinuses of dura mater and venous sinus of sclera.

2. the common venous receptacle in the early embryo attached to the posterior wall of the primitive atrium.

3. sinus of venae cavae.

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.

Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

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]

Farlex Partner Medical Dictionary © Farlex 2012

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.

The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

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).

Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

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]

Medical Dictionary for the Health Professions and Nursing © Farlex 2012

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.

Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005

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.

Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

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.

Mentioned in: Abscess, Erythromycins, Nasal Polyps, Sinusitis

Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.

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.

Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann

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]

Medical Dictionary for the Dental Professions © Farlex 2012

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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