Lateral thoracic artery
The lateral thoracic artery (long thoracic artery) originates from the second segment of the axillary artery. It runs along the lateral border of the pectoralis minor and under the pectoralis major muscle. It often anastomoses with branches of the internal thoracic artery.
The lateral thoracic artery supplies the axillary lymph nodes, serratus anterior, pectoralis major, pectoralis minor and subscapularis muscles. Additionally, it can provide blood supply to the breast in females.
This article will discuss the anatomy and function of the lateral thoracic artery.
|Branches||Lateral mammary branches, lateral cutaneous branches|
|Supply||Axillary lymph nodes, breasts, skin of the anterior thoracic wall, serratus anterior, pectoralis major, pectoralis minor and subscapularis muscles|
Origin and course
The standard anatomy textbooks most commonly consider the lateral thoracic artery to be a branch of the axillary artery. However, several more recent studies have shown that the most common origin is from the thoracoacromial artery (up to 60% of cases).
When it originates from the axillary artery, it usually arises as a second branch of the second part of the axillary artery, distal to the origin of the thoracoacromial artery.
The artery runs almost vertically downwards, along the lateral margin of the pectoralis minor muscle. It is usually covered by the pectoralis major muscle. The artery terminates around the fifth intercostal space.
Branches and supply
Along its course, the lateral thoracic artery provides several small branches that supply the structures of the anterior thoracic wall and axilla. These structures usually include:
- Axillary lymph nodes
- Skin of the lateral portion of the thoracic wall
- Serratus anterior muscle
- Pectoralis major muscle
- Pectoralis minor muscle
- Subscapularis muscle
It commonly forms anastomoses with the internal thoracic artery, particularly in females.
The lateral thoracic artery is a highly variable vessel in terms of origin and distribution.
- Occasionally, the lateral thoracic artery can be absent. When that occurs, this artery is replaced by branches of the intercostal arteries.
- The lateral thoracic artery can originate from the thoracoacromial artery or subscapular artery.
- It can also arise from the first and third part of the axillary artery.
- This artery can arise as a single vessel or it can share a common trunk with other branches of the axillary artery, most commonly with the superior thoracic artery.
- It can provide cutaneous branches that supply the skin adjacent to the lateral border of pectoralis major muscle. These branches are referred to as the superficial thoracic arteries.