Lateral thoracic artery !

The lateral thoracic artery runs down the side of the chest wall from the armpit; it supplies the outer part of the breast.

See in 3D →

Opens in the Durgical app, no sign-up needed.

What it is

A branch of the second part of the axillary artery that runs down the side of the chest along the lower edge of pectoralis minor.

What it does

Supplies serratus anterior, the pectoral muscles, the axillary nodes and the outer part of the breast.

Key facts

Origin: Second part of axillary artery (behind pectoralis minor)
Branches: Lateral mammary branches; branches to serratus anterior and pectoral muscles
Supplies: Lateral breast, serratus anterior, pectoral muscles; runs along the lower border of pectoralis minor

Relations

Course: Leaves the axillary artery behind the pectoralis minor and descends along its lower border onto the side of the chest wall
Deep: Serratus anterior, with the long thoracic nerve on its surface further back in the midaxillary line
Superficial: Axillary tail of the breast and the pectoral group of the axillary lymph nodes
Behind: Thoracodorsal nerve and vessels on the posterior axillary wall

How to find it

Not palpable. In axillary dissection it is seen running down the lateral border of the pectoralis minor onto the serratus anterior; handheld Doppler can map its skin branches before flap surgery.

On imaging

CT or MR angiography shows it running down the chest wall on the serratus anterior, along the lateral border of the pectoralis minor. It is not singled out on mammography, but on contrast breast MRI its branches appear as vessels entering the upper outer breast. Before flap surgery, CT angiography or handheld Doppler maps it.

Common problems

Enlarges to feed the breast; tied or sealed during axillary and breast surgery.

Clinical notes

Often divided in axillary dissection; the long thoracic nerve nearby must be kept, as its injury causes winging of the scapula
Breast reduction and lift operations plan their tissue pedicles to keep enough of its supply to the nipple and areola
Its perforators can carry a flap of lateral chest skin and fat to fill defects after partial mastectomy
In the male breast its lateral mammary branches are small, but it is met in surgery for gynaecomastia and male breast cancer

Anatomical variants

Arises from the thoracoacromial artery, the subscapular artery or a common trunk in a sizeable minority; it may be small and replaced by branches of the subscapular artery

Test yourself

Think of the answer, then tap the question to see it.

What does the lateral thoracic artery supply in the breast?

The lateral breast; it is the second main supply after the internal thoracic artery, and its branches enlarge in lactation.

Which nerve runs close to the lateral thoracic artery, and what does its injury cause?

The long thoracic nerve on serratus anterior; injury causes winging of the scapula.

From where does the lateral thoracic artery usually arise?

The second part of the axillary artery, behind pectoralis minor; it can also arise from the thoracoacromial or subscapular artery.

Add to my cards (3)

Educational information, not medical advice. For any symptom, see a health professional.

Its names

Official Latin (TA2): arteria thoracica lateralis TA2 4625
Official Spanish (DeCS): Arteria torácica lateral
English (TA2): Lateral thoracic artery
Also called: external mammary artery

Sources: Terminologia Anatomica (TA2); Anatomy, Thorax, Breast; Anatomy, Shoulder and Upper Limb, Axilla.

Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake

Representative model, for educational purposes only.