Lateral thoracic artery

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
• Breasts
• 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.

Anatomical variations

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.