Organ
Bundle branches
Paired routes from the His bundle into the ventricles
High-yield
Anterior and posterior left fascicles are useful teaching divisions, but septal fibers and connections vary; the left branch is not always a simple two-cord split.
Overview
The branching His axis supplies a narrow right-sided pathway and a more extensive left-sided network. The right branch descends within and beneath the septal muscle before spreading toward the right ventricle, including the moderator band. The left branch fans across the left septal surface.
Reference facts
- Location
- Along the right and left aspects of the ventricular septum, continuing toward the ventricular conduction networks
- Parts
- A slender right branch and a broad left network with anterior, posterior and variable septal components
- Blood supply
- Septal coronary branches, especially from the anterior interventricular artery, with variable posterior and AV nodal contributions
- Innervation
- Autonomic cardiac signals can influence ventricular conducting tissue
- Relations
- The right branch relates to the septomarginal trabeculation; the left spreads beneath left septal endocardium
- Function
- Distributes excitation from the His axis to the two ventricular Purkinje networks
Clinical correlation
Bundle branch block changes the sequence of ventricular activation and the ECG's QRS pattern. An isolated finding and a block associated with myocardial disease do not have the same implications.
Frequently asked questions
Where are the bundle branches located?
Along the right and left aspects of the ventricular septum, continuing toward the ventricular conduction networks.
What do the bundle branches do?
Distributes excitation from the His axis to the two ventricular Purkinje networks.
What are the parts of the bundle branches?
A slender right branch and a broad left network with anterior, posterior and variable septal components.
What is the blood supply of the bundle branches?
Septal coronary branches, especially from the anterior interventricular artery, with variable posterior and AV nodal contributions.