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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 Ia 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 Ia of the septomarginal trabecula (♂, 3 yrs)IS – interventricular septum, AW – anterior wall of the right ventricle, ST – septomarginal trabecula, APM – anterior papillary muscle, SC – lower part of the crista supraventricularis, I in black circle – septomarginal trabecula
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Figure 6: A – Sub-type Ia 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 Ia of the septomarginal trabecula (♂, 3 yrs)IS – interventricular septum, AW – anterior wall of the right ventricle, ST – septomarginal trabecula, APM – anterior papillary muscle, SC – lower part of the crista supraventricularis, I in black circle – septomarginal trabecula

Mentions: As mentioned before, the anterior papillary muscle, formerly known as the great one, is more or less firmly connected to the septomarginal trabecula. The trabecula deriving from the crista supraventricularis can remain in various topographical relations to that structure. Depending on the course of the septomarginal trabecula within the interior of the right ventricle and, above all, its connection and location in relation to the anterior papillary muscle, 4 morphological types were distinguished. In type I, the septomarginal trabecula of variable thickness was a solid structure, not segmented into septo-papillary and papillo-marginal parts. The anterior papillary muscle was characterized by its heterogeneity and variability of its location. It was residing on a “scaffold” of vertical trabeculae deriving from either the region of the interventricular septum or the apex or the interior surface of the anterior wall of the right ventricle. A case where the anterior papillary muscle was located up the anterior wall and firmly attached to it with the septomarginal trabecula reaching the wall a bit lower was also included in that type. Thus, type I included a solid trabecula which remained undivided by the anterior papillary muscle. In the studied material such a variant was observed in 5 fetal hearts (8.32%), 3 children’s (4.99%), and 3 adults’ (3%). Considering the varied location of the anterior papillary muscle in the right ventricle, two sub-types were distinguished within type I. Sub-type Ia was a configuration where a soaring papillary muscle was located at the wall, high on the vertical trabeculae and not firmly connected with the septomarginal trabecula. Its fibres derived from the anterior wall as well as the region of the right ventricular apex (Figure 6). In sub-type Ib the anterior papillary muscle was firmly connected to the anterior wall of the right ventricle, while the septomarginal trabecula reached the muscle independently, below the attachment of the muscle. Four out of 5 type I fetal hearts were classified as sub-type Ia, 1 as sub-type Ib, while 2 out of 3 children’s hearts were included in sub-type Ia and 1 in Ib. All 3 hearts of adults were classified as sub-type Ib.


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 Ia 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 Ia of the septomarginal trabecula (♂, 3 yrs)IS – interventricular septum, AW – anterior wall of the right ventricle, ST – septomarginal trabecula, APM – anterior papillary muscle, SC – lower part of the crista supraventricularis, I in black circle – septomarginal trabecula
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 6: A – Sub-type Ia 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 Ia of the septomarginal trabecula (♂, 3 yrs)IS – interventricular septum, AW – anterior wall of the right ventricle, ST – septomarginal trabecula, APM – anterior papillary muscle, SC – lower part of the crista supraventricularis, I in black circle – septomarginal trabecula
Mentions: As mentioned before, the anterior papillary muscle, formerly known as the great one, is more or less firmly connected to the septomarginal trabecula. The trabecula deriving from the crista supraventricularis can remain in various topographical relations to that structure. Depending on the course of the septomarginal trabecula within the interior of the right ventricle and, above all, its connection and location in relation to the anterior papillary muscle, 4 morphological types were distinguished. In type I, the septomarginal trabecula of variable thickness was a solid structure, not segmented into septo-papillary and papillo-marginal parts. The anterior papillary muscle was characterized by its heterogeneity and variability of its location. It was residing on a “scaffold” of vertical trabeculae deriving from either the region of the interventricular septum or the apex or the interior surface of the anterior wall of the right ventricle. A case where the anterior papillary muscle was located up the anterior wall and firmly attached to it with the septomarginal trabecula reaching the wall a bit lower was also included in that type. Thus, type I included a solid trabecula which remained undivided by the anterior papillary muscle. In the studied material such a variant was observed in 5 fetal hearts (8.32%), 3 children’s (4.99%), and 3 adults’ (3%). Considering the varied location of the anterior papillary muscle in the right ventricle, two sub-types were distinguished within type I. Sub-type Ia was a configuration where a soaring papillary muscle was located at the wall, high on the vertical trabeculae and not firmly connected with the septomarginal trabecula. Its fibres derived from the anterior wall as well as the region of the right ventricular apex (Figure 6). In sub-type Ib the anterior papillary muscle was firmly connected to the anterior wall of the right ventricle, while the septomarginal trabecula reached the muscle independently, below the attachment of the muscle. Four out of 5 type I fetal hearts were classified as sub-type Ia, 1 as sub-type Ib, while 2 out of 3 children’s hearts were included in sub-type Ia and 1 in Ib. All 3 hearts of adults were classified as sub-type Ib.

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.