Muscle
Papillary muscles
Ventricular muscles that maintain chordal support
High-yield
Papillary contraction maintains chordal tension as ventricular pressure rises; pressure differences drive valve opening and closure.
Overview
Papillary muscles project from ventricular myocardium and anchor the chordae of the atrioventricular valves. Left-sided muscles are usually arranged in anterolateral and posteromedial groups; right-sided groups are commonly described as anterior, posterior and septal. Each group may have several heads.
Reference facts
- Origin
- Ventricular myocardium; usually two main left-sided groups and three conventionally named right-sided groups, with variable heads
- Insertion
- Chordae extending to atrioventricular leaflet edges and ventricular surfaces
- Innervation
- Cardiac autonomic networks influence the myocardium; activation reaches it through cardiac conducting muscle
- Action
- Maintain leaflet support and resist prolapse during ventricular systole
- Blood supply
- Left anterolateral group often receives anterior interventricular and circumflex branches; posteromedial supply commonly follows the posterior interventricular artery
Clinical correlation
Papillary-muscle rupture after myocardial injury can cause severe acute mitral regurgitation. The posteromedial group often has a more limited arterial source than the anterolateral group, although coronary patterns vary.
Frequently asked questions
What do the papillary muscles do?
Maintain leaflet support and resist prolapse during ventricular systole.
What nerve innervates the papillary muscles?
Cardiac autonomic networks influence the myocardium; activation reaches it through cardiac conducting muscle.
Where do the papillary muscles attach?
Origin: Ventricular myocardium; usually two main left-sided groups and three conventionally named right-sided groups, with variable heads. Insertion: Chordae extending to atrioventricular leaflet edges and ventricular surfaces.
What is the blood supply of the papillary muscles?
Left anterolateral group often receives anterior interventricular and circumflex branches; posteromedial supply commonly follows the posterior interventricular artery.