The axilla, commonly known as the armpit, is the anatomical region located under the shoulder joint where the arm connects to the shoulder. It's a pyramidal space containing crucial neurovascular structures.
Components of the Axilla
The axilla is more than just a hollow area; it houses a complex network of vital structures:
- Axillary Artery: This major blood vessel supplies blood to the upper limb.
- Axillary Vein: This vein drains blood from the upper limb.
- Brachial Plexus: A network of nerves that provides sensory and motor function to the upper limb.
- Lymph Nodes: These nodes are crucial components of the immune system, filtering lymph fluid and playing a role in fighting infection.
Boundaries of the Axilla
To fully understand the axilla, it's important to define its borders:
- Apex (Superior): Cervicoaxillary canal, passage between neck and axilla.
- Base (Inferior): Formed by the skin and fascia of the armpit.
- Anterior Wall: Pectoralis major and minor muscles.
- Posterior Wall: Subscapularis, teres major, and latissimus dorsi muscles.
- Medial Wall: Serratus anterior muscle and the thoracic wall (ribs).
- Lateral Wall: Intertubercular groove of the humerus.
Clinical Significance
The axilla is a clinically significant area due to the presence of lymph nodes. It's a common site for lymph node swelling, which can indicate infection, inflammation, or even cancer. Regular self-exams and clinical examinations often involve checking for lumps or abnormalities in the axillary region. Surgical procedures, such as axillary lymph node dissection, may be performed to remove lymph nodes for staging or treatment of cancer.
