Superficial Lymphatic Vessels
These vessels (vasa lymphatica superficialia) are located in the subcutaneous adipose tissue. They originate from dense lymphatic plexuses on the palmar and dorsal surfaces of the hand. Converging, they form 8–10 large trunks that collect lymph from adjacent skin areas along their course.
Based on topography, two main groups are distinguished:
- Medial group: Vessels ascend along the basilic vein (v. basilica). Upon reaching the cubital fossa, 1–2 vessels penetrate into the cubital lymph nodes. From there, efferent pathways travel to the deep vessels of the arm. The remaining vessels of the medial group continue along the medial surface of the arm and drain directly into the axillary nodes.
- Lateral group: These pathways accompany the cephalic vein (v. cephalica). Ascending to the upper third of the arm, they penetrate deep into the tissues—into the axillary cavity—where they also terminate in the axillary lymph nodes (nodi lymphoidei axillares).
Deep Lymphatic Vessels
The main function of the deep network is the drainage of lymph from bones, joints, and muscles. In the digits, these vessels run along the lateral surfaces adjacent to the blood arteries. Passing onto the hand, they anastomose and form the palmar lymphatic plexus, the projection of which corresponds to the arterial arch.
In the forearm, lymph drains via vessels accompanying the major arteries:
- Along the ulnar artery (a. ulnaris): vessels are interrupted in the upper third of the forearm or the cubital fossa, draining into the cubital nodes (nodi lymphoidei cubitales). Lymph from the dorsum of the forearm also arrives here via pathways running with the posterior interosseous artery.
- Along the radial artery (a. radialis): pathways similarly reach the cubital fossa and terminate in the cubital nodes.
Efferent vessels of the cubital nodes merge into a single large trunk that ascends the arm along the brachial artery (a. brachialis). At the border of the middle and lower thirds of the arm, this trunk enters a brachial lymph node. From there, two vessels emerge and reach the lateral axillary nodes (nodi lymphoidei axillares laterales).
Formation of Lymphatic Trunks
The axillary nodes serve as a crucial transit station. Efferent vessels from all groups of axillary nodes unite to form the axillary lymphatic plexus (plexus lymphaticus axillaris), located along the course of the axillary and subclavian veins.
From the efferent pathways of this plexus, the major subclavian trunks—right and left (trunci subclavii dexter et sinister)—are formed, through which lymph leaves the upper limb.
Regional Lymph Drainage: Breast
The axillary nodes receive lymph not only from the upper limb but also from the mammary gland, which features a complex drainage system (superficial and deep networks with cross-anastomoses).
In addition to the main pathway to the axillary nodes, drainage is distributed by quadrants:
- From medial regions: vessels pierce the intercostal spaces and drain into the parasternal nodes (nodi lymphoidei parasternales).
- From superior and lateral regions: lymph travels to the pectoral (paramammarii, along the lateral thoracic artery) and interpectoral (interpectorales, 3–4 nodes subcutaneously or between the pectoral muscles) nodes.
- Supraclavicular pathway: vessels course anteriorly around the clavicle and head toward the supraclavicular and jugulodigastric/jugulo-omohyoid nodes.
Adjacent Lymph Nodes of the Head and Neck
Although these nodes belong to another region, border groups are often considered for completeness of the lymphatic system:
- Occipital nodes (nodi lymphoidei occipitales): 2 to 6 nodes located in the subcutaneous tissue near the superior nuchal line.
- Mastoid nodes (nodi lymphoidei mastoidei): 2–4 nodes posterior to the auricle, where the sternocleidomastoid muscle attaches.
- Parotid nodes (nodi lymphoidei parotidei): divided into deep and superficial (the latter usually 2–4, located anterior to the ear on the capsule of the gland).