The axilla, commonly known as the armpit, is a naturally occurring space located directly beneath the shoulder joint. This area serves as an anatomical passageway connecting the upper limb to the main body. This article explores its precise location, the networks of vessels and nerves it contains, and various aspects related to its function and care.
Locating the Axilla
The axilla forms a pyramid-shaped space situated at the junction where the arm meets the chest wall. Its external appearance is the concave depression known as the armpit, visible when the arm is slightly abducted. Internally, this space is defined by several surrounding structures, acting as a protected pathway for crucial elements traveling to and from the arm.
Muscles and bone form the axilla’s boundaries. The anterior wall includes the pectoralis major and minor muscles, creating the anterior axillary fold. The posterior wall is composed of muscles like the latissimus dorsi and teres major, forming the posterior axillary fold.
The medial wall consists of the upper ribs and serratus anterior muscle. The lateral wall is formed by the upper humerus bone. Superiorly, the axilla narrows into an apex, bounded by the clavicle, first rib, and scapula, connecting to the neck. The base is the skin of the armpit.
Key Structures Within the Axilla
The axilla houses several important structures, making it a significant anatomical region for the upper body. These include major blood vessels like the axillary artery and vein, responsible for circulation to and from the upper limb. The axillary artery, a continuation of the subclavian artery, delivers oxygenated blood to the arm. The axillary vein collects deoxygenated blood to return it toward the heart.
A network of nerves, the brachial plexus, also passes through the axilla. This plexus originates from spinal nerves in the neck (C5-T1) and branches out to supply motor and sensory innervation to the upper extremity. These nerves enable movement and sensation, highlighting its role in neural communication.
The axilla contains numerous lymph nodes. These small, bean-shaped organs are components of the immune system. They filter lymph fluid from the upper limb, breast, and parts of the torso, trapping foreign particles and helping to fight infections.
Common Concerns and Care
The axilla is a unique area prone to specific concerns, largely due to sweat glands and hair. Apocrine sweat glands, concentrated in this region, produce a thicker, oily sweat that, when mixed with bacteria on the skin, can lead to body odor. These glands become active during puberty.
Proper hygiene is important for managing axillary odor and maintaining skin health. Regular cleansing with mild soap helps remove bacteria and sweat buildup. Some individuals remove axillary hair, which can reduce moisture trapping and potentially lessen odor.
Swollen lymph nodes in the axilla are a common observation, indicating immune system activity. This swelling, axillary lymphadenopathy, can result from local infections in the arm, hand, or breast, or systemic conditions like viral illnesses. Vaccinations can also temporarily cause lymph node enlargement.
Most swollen lymph nodes are temporary and benign. However, they warrant attention if they persist without a clear cause, grow significantly, or are accompanied by other concerning symptoms. General care practices for the axilla include wearing breathable fabrics to promote air circulation and using deodorants or antiperspirants to manage sweat and odor.