Fibrous rings of heart

Fibrous rings of heart

Infobox Anatomy
Latin = anulus fibrosus dexter cordis, anulus fibrosus sinister cordis
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The right and left fibrous rings of heart ("anulus fibrosus cordis") surround the atrioventricular and arterial orifices, and are stronger upon the left than on the right side of the heart. The right fibrous ring is known as the "anulus fibrosus dexter cordis", and the left is known as the "anulus fibrosus sinister cordis".

The atrioventricular rings serve for the attachment of the muscular fibers of the atria and ventricles, and for the attachment of the bicuspid and tricuspid valves.

The left atrioventricular ring is closely connected, by its right margin, with the aortic arterial ring; between these and the right atrioventricular ring is a triangular mass of fibrous tissue, the "trigonum fibrosum", which represents the "os cordis" seen in the heart of some of the larger animals, as the ox and elephant.

Lastly, there is the tendinous band, already referred to, the posterior surface of the conus arteriosus.

The fibrous rings surrounding the arterial orifices serve for the attachment of the great vessels and semilunar valves, they are known as The "aortic annulus".

Each ring receives, by its ventricular margin, the attachment of some of the muscular fibers of the ventricles; its opposite margin presents three deep semicircular notches, to which the middle coat of the artery is firmly fixed.

The attachment of the artery to its fibrous ring is strengthened by the external coat and serous membrane externally, and by the endocardium internally.

From the margins of the semicircular notches the fibrous structure of the ring is continued into the segments of the valves.

The middle coat of the artery in this situation is thin, and the vessel is dilated to form the sinuses of the aorta and pulmonary artery.

ee also

*chordae tendineae
*Fibrous ring of intervertebral disk

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Look at other dictionaries:

  • fibrous rings of heart — see anulus fibrosus dexter/sinister cordis …   Medical dictionary

  • ring — 1. A circular band surrounding a wide central opening; a r. shaped or circular structure surrounding an opening or level area. SYN: anulus [TA]. 2. The closed ( i.e., endless) chain of atoms in a cyclic compound; commonly used for “cyclic” or… …   Medical dictionary

  • anulus fibrosus dexter/sinister cordis — [TA] right/left fibrous ring of heart: one of the dense fibrous rings that surround the right and left atrioventricular orifices. To these rings, either directly or indirectly, are attached the atrial and ventricular muscle fibers. The rings form …   Medical dictionary

  • anulus — SYN: ring (1). [L.] a. abdominalis SYN: deep inguinal ring. a. ciliaris SYN: ciliary body. a. conjunctivae [TA] SYN: conjunctival ring. a. femoralis [TA] SYN: femoral ring. a. fibrocartilagineus membranae tympani [TA] SYN: fibrocartilaginous ring …   Medical dictionary

  • Tendon — The tissue by which a muscle attaches to bone. A tendon is somewhat flexible, but fibrous and tough. When a tendon becomes inflamed, the condition is referred to as tendinitis or tendonitis. Inflamed tendons are at risk for rupture. Tendons are… …   Medical dictionary

  • Cardiac skeleton — (sometimes called fibrous skeleton of the heart ) refers to the structure of dense connective tissue in the heart that separates the atria from the ventricles.It is not a true skeleton, but it does provide structure and support for the heart, as… …   Wikipedia

  • Skeleton — The skeleton is composed of bones and is the framework of the body. * * * 1. The bony framework of the body in vertebrates (endoskeleton) or the hard outer envelope of insects (exoskeleton or dermoskeleton). 2. All the dry parts remaining after… …   Medical dictionary

  • trigone — 1. SYN: trigonum. 2. The first three dominant cusps (protocone, paracone, and metacone), taken collectively, of an upper molar tooth. [L. trigonum, fr. G. trigonon, triangle] t. of auditory nerve the slight prominence of the …   Medical dictionary

  • Сердце — (cor) является главным элементом сердечно сосудистой системы, обеспечивающим кровоток в сосудах, и представляет собой полый мышечный орган конусообразной формы, располагающийся за грудиной на сухожильном центре диафрагмы, между правой и левой… …   Атлас анатомии человека

  • trigonum fibrosum dextrum cordis — [TA] right fibrous trigone of heart: a thickened, irregularly triangular portion of the fibrous skeleton of the base of the heart, located between the right and left atrioventricular fibrous rings, posterior to the aortic orifice. Called also… …   Medical dictionary

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