ABSTRACT
The shape and position of the central fibrous body (CFB) and the relation between the CFB and the conduction system were observed in 30 human hearts (children: 25 cases, adult: 5 cases) in serial sections.The shape of the CFB was wedge-shaped. The CFB of each child was horizontal in position, but the CFB of each adult was nearly sagittal in position.A-V node was a long sagittal flat structure. Its left surface contacted with the CFB and the left surface of A-V node often extended processes into the CFB in the children. The processes were called archipelagos. About 80 percent of the children with superficial archipelagos, and 16 percent with deep archipelagos. The superficial archipelagos in the adults was only found in one case, but the deep archipelagos were not seen.His bundle more permanently penetrated into the right inferior part of the CFB.