Organ
Left atrium
Posterior chamber receiving pulmonary venous return
High-yield
The left atrium forms most of the cardiac base. Its relation to the esophagus is useful for transesophageal imaging and important during specialist left atrial procedures.
Overview
Blood from the lungs enters the left atrium, usually through four pulmonary-vein openings. Most of its cavity is smooth, while pectinate ridges are concentrated in the appendage. Its posterior position brings it close to the esophagus.
Reference facts
- Location
- Posterior cardiac chamber, anterior to the oblique pericardial recess and esophagus
- Parts
- Main pulmonary venous chamber, appendage and septal surface bearing the foramen-ovale flap remnant
- Blood supply
- Atrial branches, mainly from the circumflex artery with variable right-coronary contributions
- Innervation
- Cardiac autonomic plexuses, including intrinsic ganglionated networks around the atrium
- Relations
- Esophagus behind; aortic root in front of its septal region; pulmonary veins enter posteriorly
- Venous/Lymphatic drainage
- Atrial veins include the oblique vein leading toward the coronary sinus; smallest veins may drain directly into the chamber
- Function
- Receives pulmonary venous blood and assists left ventricular filling
Clinical correlation
Atrial fibrillation can promote stasis and clot formation in the left atrial appendage. A clot that leaves the left heart may reach systemic arteries, including those supplying the brain.
Frequently asked questions
Where is the left atrium located?
Posterior cardiac chamber, anterior to the oblique pericardial recess and esophagus.
What does the left atrium do?
Receives pulmonary venous blood and assists left ventricular filling.
What are the parts of the left atrium?
The parts of the left atrium are the main pulmonary venous chamber, appendage and septal surface bearing the foramen-ovale flap remnant.
What is the blood supply of the left atrium?
The left atrium is supplied by the atrial branches, mainly from the circumflex artery with variable right-coronary contributions.