Axillary node

Axillary lymph nodes or axillary nodes are a group of lymph nodes located in the axilla (underarm area), playing a crucial role in the lymphatic system of the human body. These nodes are key components in the immune response and in filtering lymph fluid of harmful substances before it returns to the bloodstream. The axillary lymph nodes are often a focal point in the diagnosis and treatment of breast cancer, as they can be the first site of cancer spread outside the breast.

Anatomy

The axillary lymph nodes are divided into several groups based on their location in the axilla:

• Pectoral (anterior) nodes: Located along the lateral edge of the pectoralis major muscle, these nodes receive lymph from the anterior thoracic wall and the breast.
• Subscapular (posterior) nodes: Situated along the lateral edge of the scapula, these nodes drain lymph from the posterior thoracic wall and a portion of the arm.
• Lateral nodes: Found along the humerus, these nodes receive lymph from the arm.
• Central nodes: Positioned in the center of the axilla, these nodes receive lymph from the three groups mentioned above.
• Apical nodes: Located at the apex of the axilla, near the clavicle, these nodes receive lymph from all the other axillary nodes.

Function

The primary function of the axillary lymph nodes is to filter lymph — a clear or white fluid made up of white blood cells and chyle — removing and destroying harmful substances such as bacteria, viruses, and cancer cells. This process is vital for the body's immune defense and helps maintain fluid balance within the body.

Clinical Significance

1. 1. 1. Breast Cancer###

In the context of breast cancer, the axillary lymph nodes are often examined to determine whether cancer cells have spread outside the breast. The presence of cancer cells in these nodes is a key factor in staging the cancer, which in turn influences treatment decisions. Procedures such as a sentinel lymph node biopsy or an axillary lymph node dissection can be performed to assess or remove these nodes.

1. 1. 1. Infections and Other Conditions###

Infections or other conditions can also affect the axillary lymph nodes, causing them to become enlarged or tender. This can be a sign of a local infection, systemic infection, or other immune responses.

Diagnosis and Treatment

The evaluation of axillary lymph nodes often involves physical examination, imaging tests such as ultrasound or MRI, and possibly a biopsy. Treatment for issues related to the axillary lymph nodes depends on the underlying cause. Infections may require antibiotics, while cancer involvement might necessitate surgery, radiation, or chemotherapy.