Morphological classification of the septomarginal trabecula in humans.

Although the septomarginal trabecula is a well-known anatomical structure, there continue to be different ways of studying it. In this study, we dissected the muscle bundles that form it, and this has enabled us to present a new classification based on the origin, path, and termination of these bundles. This study was conducted on 99 hearts removed from the cadavers of adult humans aged 18 to 82 years, of which 72 were male and 27 were female. The septomarginal trabecula presents two components in its composition: one septal and the other septal- papillary, i.e. extending from the septum to the anterior papillary muscle. The septal component may be visible macroscopically, forming a fleshy third-order column, or may only be visible by means of dissection. The septal-papillary component is always visible and is a fleshy column of either second-order or third- -order type. Another parameter takes into consideration the papillary-parietal connection, i.e. the junction of the septomarginal trabecula with the anterior papillary muscle, which may be single or present ramifications to the anterior wall and/or apex. Taking these criteria as references, we have classified the septomarginal trabecula into eight types.