Muscle fascicle

In anatomy, a muscle fascicle is a bundle of skeletal muscle fibers surrounded by perimysium, a type of connective tissue. (There is also a nerve fascicle of axons.)

Specialized muscle fibers in the heart that transmit electrical impulses from the atrioventricular node (AV Node) to the Purkinje fibers are fascicles, also referred to as bundle branches. These start as a single fascicle of fibers at the AV node called the bundle of His that then splits into three bundle branches: the right fascicular branch, left anterior fascicular branch, and left posterior fascicular branch.