The Axilla – Anatomy and Lymphatics (Video Notes)

A set of vocabulary-style flashcards covering the major anatomical features, walls, vessels, and lymph nodes of the axilla as described in the video notes.

Axilla

A pyramid-shaped space (armpit) between the upper arm and chest that serves as a passage for nerves, blood vessels, and lymph from the root of the neck to the upper limb.

Apex of the axilla

Upper end of the axilla; continues into the root of the neck via the cervicoaxillary canal; bounded anteriorly by the clavicle, posteriorly by the upper border of the scapula, and medially by the first rib.

Cervico-axillary canal

Passage between the neck and the upper limb through which structures pass; bounded anteriorly by the clavicle, posteriorly by the upper border of the scapula, and medially by the first rib.

Base of the axilla

Inferior boundary of the axilla, formed by skin and fascia.

Anterior wall (axilla)

Formed by the pectoralis major, pectoralis minor, and subclavius muscles.

Posterior wall (axilla)

Formed by the subscapularis, latissimus dorsi, and teres major muscles.

Medial wall (axilla)

Formed by the upper four or five ribs with intercostal spaces covered by serratus anterior.

Lateral wall (axilla)

Formed by the coracobrachialis and biceps brachii in the bicipital groove of the humerus.

Axillary artery

Major artery of the axilla; begins at the lateral border of the first rib as a continuation of the subclavian, ends at the lower border of teres major where it becomes the brachial; enclosed in the axillary sheath.

First part of the axillary artery

Portion above the pectoralis minor muscle.

Second part of the axillary artery

Portion behind the pectoralis minor muscle.

Third part of the axillary artery

Portion below the pectoralis minor muscle.

Pectoralis minor relation to the axillary artery

The pectoralis minor crosses in front of the axillary artery and divides it into three parts.

Axillary vein

Formed by the union of the basilic and brachial veins at the inferior border of the teres major; courses on the medial side of the axillary artery; ends at the lateral border of the first rib as the subclavian vein; receives tributaries including those corresponding to axillary artery branches and cephalic vein.

Cephalic vein (lymphatic note)

A superficial vein; its lymphatic drainage travels to apical and infraclavicular axillary nodes; venous drainage contributes to the axillary system.

Pectoral (anterior) lymph nodes

Nodes along the medial wall of the axilla around the inferior border of the pectoralis minor; receive lymph from the anterior thoracic wall and most of the breast.

Subscapular (posterior) lymph nodes

Nodes along the posterior axillary fold; receive lymph from the posterior thoracic wall and scapular region.

Humeral (lateral) lymph nodes

Nodes along the lateral wall of the axilla; receive lymph from the upper limb, except lymph from the cephalic vein pathway which drains to apical or infraclavicular nodes.

Central lymph nodes

Deep nodes near the base of the axilla, deep to the pectoralis minor; receive efferents from the pectoral, subscapular, and humeral groups and drain to the apical nodes.

Apical lymph nodes

Nodes at the apex of the axilla along the medial side of the axillary vein and first part of the axillary artery; receive lymph from all other axillary groups and proximal cephalic vein; efferents pass through the cervicoaxillary canal to form the subclavian lymphatic trunk.

Subclavian lymphatic trunk

Formed by efferent vessels from the apical nodes; may join the right lymphatic duct on the right or the thoracic duct on the left.

Interpectoral (between pectoral muscles) nodes

Nodes located between the pectoralis major and minor; part of the axillary lymphatic drainage network.

Brachial plexus in the axilla

A network of nerves supplying the upper limb, located within the axillary region.

Axillary contents (general)

The axilla contains the axillary artery, axillary vein, brachial plexus, and axillary lymph nodes.

Cervicoaxillary canal (revisited)

Pathway for vessels and nerves from the neck to the upper limb; crucial for communications between neck and arm.

Axillary lymph node groups (overall)

Five principal groups arranged to reflect the pyramid shape: pectoral (anterior), subscapular (posterior), humeral (lateral), central, and apical.