The Anatomical Description of the Mitroaortic Orifice [600851]

The Anatomical Description of the Mitroaortic Orifice
147Vol. XII – Nr. 2 – 2013 ORIGINAL PAPERSRevista Română de Anatomie funcțională ”i clinică, macro- ”i microscopică ”i de Antropologie
THE ANATOMICAL DESCRIPTION
OF THE MITROAORTIC ORIFICE
C.M. Pantu1, M. Enyedi1, R. Stanciulescu1, I.Gh. Popescu2, F .M. Filipoiu1
University of Medicine and Pharmacy “Carol Davila”, Bucharest
1. Department of Morphological Sciences
Anatomy Discipline
2. Emergency Clinical Hospital
Department of Orthopaedics
THE ANATOMICAL DESCRIPTION OF THE MITROAORTIC ORIFICE (Abstract) This study
aimed to describe the mitroaortic orifice and its important relation with the tricuspid orifice, themitroaortic continuity, the fibrous trigones and the aoric root, in order to identify the muscularfibers disposal at the base of the two ventricles. The subepi-subendocardic continuity, thesuperficial fibers situated in the vicinity of the cusp’s ventricular insertions and the subendocardicfibers were emphasized. The mechanisms in which the aortic diameter is kept constant and theimportant role of the mitroaortic orifice in the dynamic of the heart are important in order tounderstand the cardiac pathology involving the mitral and the aortic valves. The mitroaorticorifice presents not only an anatomical individuality but also a functional one in the cardiacdynamics due to its involvement in the retrotorsion movement of the ventricular base. Key
words : MITROAORTIC ORIFICE, MYOCARDIAL FIBERS, AORTIC ROOT
INTRODUCTION
This study aimed to describe the mitroaortic
orifice and its important relation with the tri-cuspid orifice, the mitroaortic continuity, thefibrous triangles and the aortic root, in order toidentify the muscular fibers disposal at the baseof the two ventricles.
MATERIAL AND METHODS
Dissection on adult hearts, harvested from
cadavers preserved in formaldehyde solution.The results were photographed using high-defi-nition digital cameras.
RESULS AND DISCUSSIONS
The myocardic wall presents at the base of
the ventricles two orifices: mitral and aorticaorifice. After the removal of the aorta and ofthe left atrium we may describe it as a singleorifice, the mitroaortic orifice. This orifice isdivided by the mitroaortic continuity (1). Themitroaortic orifice presents thick borders andat the ventricular roots of the cusps the direc-tion of the superficial fibers is continuous with
that of the subendocardic ones. Therefore, be-
tween the mitral orifice and the tricuspid ori-fice is a subendo-subepicardic transition which
corresponds to the middle part of the interven-
tricular crest. This continuity supports the baseof the left ventricle when traction towards theapex of the heart. The observation of the dis-posal and orientation of the subepicardic fibersof this orifice indicates that their contractionproduces the clockwise rotation of the mitro-aortic orifice and with this the retrotorsion ofthe ventricular base (2).
The middle myocardial layer is circular and
well represented towards the ventricular base.Its contraction during the systole should also
close the aortic orifice, but the fibrous skeleton
prevents that. The fibrous triangles situated atthe base of aorta are anchored by myocardialfibers (3,4). The triangle formed between thenon-coronary and right coronary leaflets of theaortic valve at its base is continuous with the

C.M. Pantu et al.
148membranous septum. The fibrous triangle in-
terposes between the left ventricular outflow
tract and the right side of the transverse sinus
of the pericardium (3).
Fibers inserting on the tendinous center and
on the membranous septum supports the supe-rior part of the septum and prevents the septalcrest to act as a sphincter-like structure.
The superficial fibers of the mitroaortic ori-
fice present a divergent, radial orientation,traction the root of the ventricular cusps, thusmaintaining the contour of the orifice. Themost mobile part of the mitroaortic orifice isthe mural part (5).
CONCLUSIONS
The mitroaortic orifice presents not only an
anatomical individuality but also a functionalone in the cardiac dynamics due to its involve-ment in the retrotorsion movement of the ven-tricular base. The mitroaortic orifice is gov-erned by a subepi-subendocardial transition whichacts together with the two fibrous triangles inmaintaining an open aortic orifice during theventricular systole.
Fig. 1. Transverse section through the mitral
valve. Superior view. We may observe that the
subvalvular infundibulum is not fusing with the
left ventricular wall. This is the anatomical base
of the Ross cardiac operation.
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