aortic vestibule

(redirected from Sibson aortic vestibule)

a·or·tic ves·ti·bule

the anterosuperior portion of the left ventricle of the heart immediately below the aortic orifice, having fibrous walls and affording room for the segments of the closed aortic valve.

a·or·tic ves·ti·bule

(ā-ōr'tik ves'ti-byūl) [TA]
The anterosuperior portion of the left ventricle of the heart immediately below the aortic orifice, having fibrous walls and affording room for the segments of the closed aortic valve.


Francis, English anatomist, 1814-1876.
Sibson aortic vestibule - the anterosuperior portion of the left ventricle of the heart immediately below the aortic orifice. Synonym(s): aortic vestibule
Sibson aponeurosis - Synonym(s): suprapleural membrane
Sibson fascia - Synonym(s): suprapleural membrane
Sibson groove - a groove occasionally seen on the outer side of the thorax, formed by the prominent lower border of the pectoralis major muscle.
Sibson muscle - an occasional independent muscular fasciculus between the scalenus anterior and medius and having the same action and innervation. Synonym(s): scalenus minimus muscle


pertaining to or emanating from the aorta. See also aortic arch.

aortic aneurysm
occurs most often in dogs, where it is caused by Spirocerca lupi larvae, turkeys and primates, causing dyspnea, cyanosis and coughing. May be congenital affecting the aortic trunk and the arch sometimes associated with aneurysm of an aortic sinus. See also copper nutritional deficiency.
aortic aneurysm, inherited
see inherited aortic aneurysm.
aortic annulus fibrosus
the fibrous ring in the wall of the root of the aorta. In the bovine heart the ring carries the ossa cordis (see os2 cordis).
aortic base rupture
rupture of the vessel just above the semilunar valves.
aortic bodies
small neurovascular structures on either side of the aorta in the region of the aortic arch. The left body is located at the angle between the left subclavian artery and the aorta, and the right at the junction of the right subclavian and right common carotid arteries. They contain chemical receptors which send impulses through the afferent branches of the vagus nerve and are involved in regulating respiration so as to ensure an appropriate partial pressure of oxygen in the arterial blood.
aortic body tumors
single or multiple nodules within the pericardial sac near the base of the heart. Malignant tumors may invade the anterior mediastinum. Called also heart base tumor.
aortic bulb
the dilated part of the aorta at its origin, caused by the swellings of the aortic sinuses.
aortic coarctation
constriction of the aorta at the site of entry of the ductus arteriosus causing a syndrome similar to that of stenosis of the aortic valve.
aortic cystic medionecrosis
pools of ground substance within the elastic media of the aorta. May predispose to arterial aneurysm but this material is present in the aortas of normal horses.
aortic depressor nerve
pressure receptors in the aortic arch and thoracic aorta which assist in maintaining circulatory equilibrium by communicating pressure changes through the aortic depressor nerve, an afferent branch of the vagus nerve; stimulation causes heart slowing and vasodilation.
aortic dextraposition
the aorta receives blood from the right ventricle. There are a number of variations of the basic defect. The common one is the aorta overriding the septum, which is defective, so that the aorta receives blood from both ventricles. The clinical syndrome includes dyspnea and cyanosis from birth, usually with a loud systolic murmur. Affected animals are not viable.
aortic embolism
occurs in cats in association with feline cardiomyopathy and rarely in dogs. Acute pain with paresis to paralysis in the hindlegs, cold, cyanotic feet and no femoral pulse are signs of the condition.
aortic hiatus
an opening in the diaphragm through which the aorta, thoracic duct, the right and/or left azygos veins pass.
aortic-ilial embolism
see iliac artery thrombosis.
aortic mineralization
is one of the early lesions in poisoning by plants that induce mineralization of tissues, e.g. solanummalacoxylon. In combination with lesions in the myocardium causes a syndrome of congestive heart failure.
aortic nerve
see cardiac depressor nerve.
aortic palpation
the aorta is easily palpable per rectum in cattle and horses; valuable as a clinical sign only in cases of thrombosis at the bifurcation; incision at this point has been used as a means of euthanasia in an emergency.
aortic-pulmonary window
an anomaly of the aorta in which there is an opening between the ascending portion of the aorta and the pulmonary artery; clinical signs are similar to those of patent ductus arteriosus, but surgical correction is much more difficult.
aortic regurgitation
see valvular regurgitation.
aortic root
the part of the aorta attached to the atrioventricular fibrous rings and myocardium.
aortic rupture
1. in horses is caused by weakening of the wall of the aorta by migrating strongyle larvae. In cattle the cause may be onchocerciasis, in pigs experimental diets deficient in copper. Sudden death results from cardiac tamponade or dissecting aneurysm into the ventricular muscle.
2. sudden death in growing turkeys due to dissecting aneurysmal rupture of the aorta and death due to internal hemorrhage; the cause is unknown. Copper deficiency is suspected as a cause in several animal species.
aortic sac
the merged ventral aortae of the embryo which supplies blood to the aortic arches.
aortic septal defect
a congenital anomaly in which there is abnormal communication between the ascending aorta and the pulmonary artery just above the semilunar valves.
aortic sinus
the three pouch-like dilatations of the aortic bulb which carry the cusps of the aortic valve. The coronary arteries arise from the left caudal and the cranial sinuses.
aortic subvalvular stenosis
in dogs and pigs is possibly an inherited defect. Characterized by stenosis of the aorta just below the semilunar valves. In pigs, it causes congestive heart failure in the newborn, but in affected dogs severity increases with age so that clinical effects may not be apparent until the patients are older.
aortic thromboembolism
thrombosis is the usual forerunner of embolism, pieces of the thrombus breaking off the main mass and lodging in more distal parts of the vascular system. See also aortic embolism (above), verminous mesenteric arteritis, iliac artery thrombosis.
Enlarge picture
Aortic thromboembolism in a cat. By permission from Nelson RW, Couto CG, Small Animal Internal Medicine, Mosby, 2003
aortic valve
the valve at the entrance to the aorta from the left ventricle made up of three semilunar leaflets or valvulae.
aortic valve rupture
rupture of the medial cusp is recorded as a cause of sudden death in horses usually as a sequel to endocarditis.
aortic valvular disease
stenosis is rarely an acquired disorder, but may be an inherited defect in several species. In cats and rarely dogs, restrictive cardiomyopathy may be a cause of subvalvular aortic obstruction. Valvular incompetence may be congenital or acquired and results in diastolic overloading of the left ventricle with a characteristic water-hammer pulse and diastolic murmur. See also aortic stenosis, aortic subvalvular stenosis (above).
aortic vestibule
the cranial part of the left ventricular cavity leading to the root of the aorta in the avian heart.


a space or cavity at the entrance to another structure.

aortic vestibule
a small space at the root of the aorta.
auricular vestibule
an oval cavity in the middle of the bony labyrinth.
ear vestibule
see vestibular apparatus.
laryngeal vestibule
the part of the larynx between the entrance (aditus laryngis) and the vocal folds (rima glottidis).
mouth vestibule
see oral vestibule (below).
nasal vestibule
the anterior part of the nasal cavity.
oral vestibule
the portion of the oral cavity bounded on the one side by teeth and gingivae, or the residual alveolar ridges, and on the other by the lips (labial vestibule) and cheeks (buccal vestibule).
pharyngeal vestibule
1. the fauces.
2. oropharynx.
vaginal vestibule
see vaginal vestibule.