Collaterals, too, are not limited to those which connect the regular meridians (channels), but also include "grandson" collaterals which branch off of the regular meridians and disappear into the surface structure of the body. Needham says that it is this that creates the impression of abstractness and makes the system difficult to understand.
『絡』也不限於為正經提供聯接的絡，因為還有『孫絡』，從正經分出去，消失在人體的表面組織裡」，李約瑟說，這就造成了經絡的抽象印象，而讓人難以理解。