The Axilla

The Axilla

Definition Is the space between the upper arm and the side of the thorax Contents:- Neurovascular structures – axillary artery the trunks and cords of the brachial plexus Lymph nodes A large number of lymph glands Branches of the intercostal nerves Fat and loose areolar tissue.

The boundaries of axilla Anteriorly - pectoralis major, pectoralis minor, subclavius and clavi-pectoral fascia Posteriorly - subscapularis teres major and latissimus dorsi Medially - serratus anterior and the first 4 ribs intercostal muscles Laterally - the anterior and posterior walls converge, the space is narrow, and bounded by the humerus, the Coracobrachialis, and the Biceps brachii.

The apex of the axilla is directed upward toward the root of the neck The apex is the interval between the first rib, the superior border of the scapula, the clavicle The axillary vessels and nerves pass through the apex The base is at the bottom and is covered by skin and a thick layer of fascia, the axillary fascia The base is broad at the chest but narrow and pointed at the arm

Applied Anatomy The axillary tail of the breast is situated in the axilla and may be involved in a cancerous growth The Lymph Nodes in the axilla are the most frequently involved in ca breast Blockade of the axillary nodes will cause lymphoedema of the whole of the upper limb.

Brachial Plexus

The base is broad at the chest but narrow and pointed at the arm It is formed by the integument and a thick layer of fascia, the axillary fascia,

Rotator Cuff posterior

Muscles attached to the scapula

Posterior Muscles

Medial Muscles

Muscle of the posterior boundary