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Morphogenetic aspects of the septomarginal trabecula in the human heart.

Kosiński A, Kozłowski D, Nowiński J, Lewicka E, Dąbrowska-Kugacka A, Raczak G, Grzybiak M - Arch Med Sci (2010)

Bottom Line: In most cases the trabecula originated from the upper part of the interventricular septum, separating at an angle increasing proportionally to the number of branches of the crista supraventricularis as well as the number of secondary trabeculae.The most common was type III, the undivided trabecula, tightly connecting with the anterior papillary muscle.Based on the results of the following study we propose a hypothesis on the genesis of respective parts of the septomarginal trabecula and a plausible sequence of changes they undergo during human ontogenesis and phylogenesis of the primates.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Anatomy, Medical University of Gdansk, Poland.

ABSTRACT

Introduction: The septomarginal trabecula is a constant element of the anatomy of the human heart, which connects the interventricular septum and the anterior wall of the right ventricle. Considering the diversity of opinions about the structure and numerous studies suggesting its important role in haemodynamics and conduction of electrical impulses in the heart, we decided to study this element in detail.

Material and methods: The research was conducted on 220 human hearts. Attention was mainly paid to the structure and topography of the trabecula. Its relation to the anterior papillary muscle was also a part of the study.

Results: The presence of this morphologically diverse element was confirmed in each of the studied hearts. In most cases the trabecula originated from the upper part of the interventricular septum, separating at an angle increasing proportionally to the number of branches of the crista supraventricularis as well as the number of secondary trabeculae. The criteria established for the study, which included the course of the trabecula in the lumen of the right ventricle and its relation to the anterior papillary muscle, let us distinguish 4 types of septomarginal trabecula (I, II, III, IV). The most common was type III, the undivided trabecula, tightly connecting with the anterior papillary muscle.

Conclusions: Based on the results of the following study we propose a hypothesis on the genesis of respective parts of the septomarginal trabecula and a plausible sequence of changes they undergo during human ontogenesis and phylogenesis of the primates.

No MeSH data available.


A – Sub-type IVa of the septomarginal trabecula: a) horizontal cross-section through the lumen of the right ventricle; b) sagittal cross-section through the lumen of the right ventricle. B – Interior of the right ventricle; sub-type IVa of the septomarginal trabecula (♂, 40 yrs)IS – interventricular septum, AW – anterior wall of the right ventricle, APM – anterior papillary muscle, ST – septomarginal trabecula: a – septo-papillary segment, b – papillo-marginal segment, SC – lower part of the crista supraventricularis, Ia in black circle – septo-papillary segment of the septomarginal trabecula, Ib in black circle – papillo-marginal segment of the septomarginal trabecula
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Figure 9: A – Sub-type IVa of the septomarginal trabecula: a) horizontal cross-section through the lumen of the right ventricle; b) sagittal cross-section through the lumen of the right ventricle. B – Interior of the right ventricle; sub-type IVa of the septomarginal trabecula (♂, 40 yrs)IS – interventricular septum, AW – anterior wall of the right ventricle, APM – anterior papillary muscle, ST – septomarginal trabecula: a – septo-papillary segment, b – papillo-marginal segment, SC – lower part of the crista supraventricularis, Ia in black circle – septo-papillary segment of the septomarginal trabecula, Ib in black circle – papillo-marginal segment of the septomarginal trabecula

Mentions: In the final type (IV) a septo-papillary segment connecting the interventricular septum with the anterior papillary muscle, and a papillo-marginal segment between the muscle and the anterior wall of the right ventricle, were distinguished. This type was found in 2 hearts of fetuses (3.33%), 8 of children (13.22%), and 44 of adults (44%). The septo-papillary part was a solid, well developed segment of the septomarginal trabecula, while the other, papillo-marginal part was characterized by high variability with regard to its development and topography. Considering the facts presented above, three sub-types were distinguished within type IV. In sub-type IVa a centrally located anterior papillary muscle divided the septomarginal trabecula into two parts. The single, solid papillo-marginal part, in terms of length and size, was similar to the septo-papillary one. In most cases it ran horizontally in the ventricle, to some extent as an elongation of the septo-papillary segment (Figure 9). This configuration was not found in the hearts of fetuses, but was clearly visible in 2 cases of children and 12 of adults. In sub-type IVb a well-developed and horizontally running septo-papillary segment tightly connected at its distal end with the anterior papillary muscle located parietally (Figure 2B). The papillo-marginal segment began at the base of the muscle and ran steeply towards the anterior wall and the apex of the right ventricle. Similarly to the septo-papillary one, this segment was also well developed and clearly distinguished itself from other morphological elements in gross anatomy of the right ventricle. It is worth emphasizing that both segments met almost at a right angle. In the examined material, this form was found in 2 hearts of fetuses (3.33%), 3 of children (5.0%) and 19 of adults (19%). The last sub-type (IVc) was characterized by the presence of a well-developed, solid septo-papillary segment running crosswise through the lumen of the ventricle. On the other hand, the papillo-marginal part created a morphologically heterogeneous structure highly variable in its size, course and – above all – the number of trabeculae branching from the muscle. In most cases, a few short muscle branches ran radially and by different tracks, from the area of its base towards the anterior wall. The presence of such a configuration was not confirmed in the hearts of fetuses, but it was found in 3 cases of children (5%) and 13 hearts of adults (13%). Table IV presents a detailed analysis.


Morphogenetic aspects of the septomarginal trabecula in the human heart.

Kosiński A, Kozłowski D, Nowiński J, Lewicka E, Dąbrowska-Kugacka A, Raczak G, Grzybiak M - Arch Med Sci (2010)

A – Sub-type IVa of the septomarginal trabecula: a) horizontal cross-section through the lumen of the right ventricle; b) sagittal cross-section through the lumen of the right ventricle. B – Interior of the right ventricle; sub-type IVa of the septomarginal trabecula (♂, 40 yrs)IS – interventricular septum, AW – anterior wall of the right ventricle, APM – anterior papillary muscle, ST – septomarginal trabecula: a – septo-papillary segment, b – papillo-marginal segment, SC – lower part of the crista supraventricularis, Ia in black circle – septo-papillary segment of the septomarginal trabecula, Ib in black circle – papillo-marginal segment of the septomarginal trabecula
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3298343&req=5

Figure 9: A – Sub-type IVa of the septomarginal trabecula: a) horizontal cross-section through the lumen of the right ventricle; b) sagittal cross-section through the lumen of the right ventricle. B – Interior of the right ventricle; sub-type IVa of the septomarginal trabecula (♂, 40 yrs)IS – interventricular septum, AW – anterior wall of the right ventricle, APM – anterior papillary muscle, ST – septomarginal trabecula: a – septo-papillary segment, b – papillo-marginal segment, SC – lower part of the crista supraventricularis, Ia in black circle – septo-papillary segment of the septomarginal trabecula, Ib in black circle – papillo-marginal segment of the septomarginal trabecula
Mentions: In the final type (IV) a septo-papillary segment connecting the interventricular septum with the anterior papillary muscle, and a papillo-marginal segment between the muscle and the anterior wall of the right ventricle, were distinguished. This type was found in 2 hearts of fetuses (3.33%), 8 of children (13.22%), and 44 of adults (44%). The septo-papillary part was a solid, well developed segment of the septomarginal trabecula, while the other, papillo-marginal part was characterized by high variability with regard to its development and topography. Considering the facts presented above, three sub-types were distinguished within type IV. In sub-type IVa a centrally located anterior papillary muscle divided the septomarginal trabecula into two parts. The single, solid papillo-marginal part, in terms of length and size, was similar to the septo-papillary one. In most cases it ran horizontally in the ventricle, to some extent as an elongation of the septo-papillary segment (Figure 9). This configuration was not found in the hearts of fetuses, but was clearly visible in 2 cases of children and 12 of adults. In sub-type IVb a well-developed and horizontally running septo-papillary segment tightly connected at its distal end with the anterior papillary muscle located parietally (Figure 2B). The papillo-marginal segment began at the base of the muscle and ran steeply towards the anterior wall and the apex of the right ventricle. Similarly to the septo-papillary one, this segment was also well developed and clearly distinguished itself from other morphological elements in gross anatomy of the right ventricle. It is worth emphasizing that both segments met almost at a right angle. In the examined material, this form was found in 2 hearts of fetuses (3.33%), 3 of children (5.0%) and 19 of adults (19%). The last sub-type (IVc) was characterized by the presence of a well-developed, solid septo-papillary segment running crosswise through the lumen of the ventricle. On the other hand, the papillo-marginal part created a morphologically heterogeneous structure highly variable in its size, course and – above all – the number of trabeculae branching from the muscle. In most cases, a few short muscle branches ran radially and by different tracks, from the area of its base towards the anterior wall. The presence of such a configuration was not confirmed in the hearts of fetuses, but it was found in 3 cases of children (5%) and 13 hearts of adults (13%). Table IV presents a detailed analysis.

Bottom Line: In most cases the trabecula originated from the upper part of the interventricular septum, separating at an angle increasing proportionally to the number of branches of the crista supraventricularis as well as the number of secondary trabeculae.The most common was type III, the undivided trabecula, tightly connecting with the anterior papillary muscle.Based on the results of the following study we propose a hypothesis on the genesis of respective parts of the septomarginal trabecula and a plausible sequence of changes they undergo during human ontogenesis and phylogenesis of the primates.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Anatomy, Medical University of Gdansk, Poland.

ABSTRACT

Introduction: The septomarginal trabecula is a constant element of the anatomy of the human heart, which connects the interventricular septum and the anterior wall of the right ventricle. Considering the diversity of opinions about the structure and numerous studies suggesting its important role in haemodynamics and conduction of electrical impulses in the heart, we decided to study this element in detail.

Material and methods: The research was conducted on 220 human hearts. Attention was mainly paid to the structure and topography of the trabecula. Its relation to the anterior papillary muscle was also a part of the study.

Results: The presence of this morphologically diverse element was confirmed in each of the studied hearts. In most cases the trabecula originated from the upper part of the interventricular septum, separating at an angle increasing proportionally to the number of branches of the crista supraventricularis as well as the number of secondary trabeculae. The criteria established for the study, which included the course of the trabecula in the lumen of the right ventricle and its relation to the anterior papillary muscle, let us distinguish 4 types of septomarginal trabecula (I, II, III, IV). The most common was type III, the undivided trabecula, tightly connecting with the anterior papillary muscle.

Conclusions: Based on the results of the following study we propose a hypothesis on the genesis of respective parts of the septomarginal trabecula and a plausible sequence of changes they undergo during human ontogenesis and phylogenesis of the primates.

No MeSH data available.