The Left Internal Mammary Artery (LIMA) is a crucial blood vessel, recognized for its significant role in advanced medical procedures. This article clarifies its location and medical importance.
Understanding the LIMA: Full Name and Origin
The LIMA, also known as the Left Internal Thoracic Artery (LITA), originates from the subclavian artery in the upper chest and neck. It typically arises about 2.5 centimeters above the collarbone, then descends into the chest cavity alongside the internal thoracic vein.
Its Anatomical Journey
The LIMA follows a precise path down the front of the chest. It descends vertically along the inner surface of the anterior chest wall, positioned 1 to 2 centimeters to the side of the sternum. This course places it behind the upper six costal cartilages, which connect the ribs to the sternum. The artery runs within a space between muscle layers, between the internal intercostal muscles and the transversus thoracis muscle. Along its journey, the LIMA provides blood supply to structures including the anterior chest wall, the breast, and parts of the superior abdominal wall through its branches.
The LIMA’s Medical Significance
The LIMA is highly valued in medicine, especially as the preferred conduit in coronary artery bypass grafting (CABG). CABG is a surgical procedure designed to restore blood flow to areas of the heart that are not receiving enough oxygen-rich blood due to blocked or narrowed coronary arteries. During this surgery, a healthy blood vessel, like the LIMA, is used to create a new pathway around the blocked section, allowing blood to bypass the obstruction.
The LIMA is considered the “gold standard” for bypassing blockages, particularly for the left anterior descending (LAD) artery, which is a major vessel supplying the heart. Its superior long-term patency rates mean it remains open and functional for many years after surgery, often exceeding 90% at 10 years, compared to other graft types like saphenous veins. The LIMA’s natural proximity to the heart, especially the LAD, facilitates its use in bypass procedures. Additionally, its size often closely matches that of the coronary arteries, contributing to successful grafting.
A significant advantage of the LIMA is its inherent resistance to atherosclerosis, the hardening and narrowing of arteries due to plaque buildup. This resistance is attributed to unique biological qualities within its vessel wall, which help it maintain its integrity and function over time. These combined characteristics make the LIMA an exceptional choice for improving blood flow to the heart muscle.