trabeculations

Trabeculations are irregular beams or ridges that form a network within a tissue or organ. They can be composed of muscle fibers or connective tissue and serve to increase surface area, provide structural support, or help with functional processes such as conduction in the heart.

In the heart, ventricular trabeculations line the endocardial surface as trabeculae carneae and are more prominent in the fetal heart and in certain physiological states. The atrial wall contains pectinate muscles, a form of trabeculation, that subdivide the atrial chamber. During development, the trabecular myocardium forms the initial muscular framework of the ventricles before the compact layer fully develops. The arrangement of trabeculations influences wall stiffness, blood flow patterns, and electrical conduction in the issuing myocardium.

Clinical relevance arises when trabeculation patterns become markedly abnormal. Excessive trabeculation in the left ventricle can be seen in left ventricular noncompaction cardiomyopathy, a condition characterized by a thick, noncompacted myocardial layer and deep intertrabecular recesses. Diagnosis typically relies on imaging criteria obtained by echocardiography or cardiac magnetic resonance imaging.

Beyond the heart, trabeculations contribute to the internal architecture of several organs. In the spleen, trabeculae extend from the capsule into the parenchyma; in bone, trabeculae form the lattice-like structure of cancellous (spongy) bone. Across tissues, trabeculations are a common structural feature with diverse developmental roles and clinical implications.