Axillary lymph nodes
|Axillary lymph nodes|
|Function:||Receive lymph from breast, thoracic wall and upper limb|
|Lymphatic drainage:||From breast, thoracic wall and upper limb|
|Search for Axillary lymph nodes in Gray's.|
Normally impalpable, enlarged lymph nodes may be palpated on examination of the axilla.
The lymph nodes are divided into groups by their anatomical site. Various different classifications have been used; the 'stations' or 'levels' (of dissection) in breast cancer surgery are quite different from the anatomical and functional groupings.
The anatomical classification is based on groups of lymph nodes and may be functionally significant. The different nodes can be easily remembered by the acronym 'APICAL' - anterior, posterior, infraclavicular, central, apical and lateral.
The anterior nodes (pectoral nodes, medial nodes; sometimes inferior nodes) are four to five nodes lying along the inferolateral border of pectoralis major, related to the lateral thoracic artery. Afferents drain the skin and muscle of the anterolateral thoracic wall, as well as the central and lateral breast. Efferents pass to the central and apical nodes.
The posterior nodes (subscapular nodes, inferior nodes) are six or seven nodes on the lower margin of the posterior wall of the [[axilla], along the course of the subscapular artery. Its afferents drain the skin and muscle of the posterior thoracic wall as well as the lower posterior neck. Its efferents pass to the central nodes.
The infraclavicular nodes (subclavicular nodes) are two or three nodes situated superiorly and posteriorly to the axillary artery, inferior to the clavicle. They receive lymph from the superficial vessels around the cephalic vein. Their efferents drain directly into the apical nodes, to which they are closely associated.
The central nodes (intermediate nodes)are a group of three or four nodes in the adipose tissue at the base of the axilla. Its afferents are from the lateral, anterior and posterior nodes; its efferents drain into the apical nodes.
The apical nodes are a group of five to ten glands, partly posterior and partly superior to pectoralis minor. It has afferents from the superior breast and mammary tail, as well as receiving afferents from all other groups of the axilla. Its efferent vessels unite to form the subclavian trunk.
The lateral nodes are a group of four to six nodes, lying medial and posterior to the axillary vein along the lateral wall of the [[axilla]. Afferent vessels to these nodes drain the upper limb, excepting the superficial vessels around the cephalic vein. Its efferent vessels drain to the infraclavicular nodes, apical nodes and central nodes of the axilla as well as the inferior deep cervical lymph nodes.
The surgical classification is used in axillary dissection for breast cancer. It is entirely based on the relationship of the lymph nodes to pectoralis minor. The levels usually refer to a dissection, so a 'level 3 dissection' will have removed nodes from levels 1, 2 and 3.
Level 1 nodes
Level 1 includes all those nodes inferior to the inferolateral border of pectoralis minor. It is usually comprised of the lateral, anterior and posterior nodes.
Level 2 nodes
Level 2 consists of those nodes posterior to pectoralis minor. It includes the central nodes and some of the apical nodes.
Level 3 nodes
Level 3 consists of those nodes beyond the superior border of pectoralis minor. It includes the remaining apical nodes and infraclavicular nodes.
- Superior breast (to apical nodes)
- Central and lateral breast (to anterior nodes)
- Superficial vessels around the cephalic vein (to infraclavicular nodes)
- Remaining lymphatics of the upper limb (to lateral nodes)
- Lower posterior neck (to posterior nodes)
- Anteriolateral thoracic wall (to anterior nodes)
- Posterior thoracic wall (to posterior nodes)
Variants of the anatomical classification
The anatomical classification varies widely, and it is difficult to find two authors who agree on grouping of the axillary lymph nodes. Part of the problem is that the groups are often indistinct and blend with one another. Some exclude the infraclavicular nodes (e.g. Moore) whilst others blend these with apical group (e.g. the original Gray's Anatomy, which many other sources copy). Misnik studied 25 axillae at post-mortem and concluded that there were six groups: lateral, medial, posterior, inferior, central and apical; unfortunately the original text is in Russian, so the composition of the described inferior group remains unclear.
The reason for such variability of classification is the relatively arbitrary grouping of nodes. Sites of the individual nodes vary widely, and may even change with age or sex. Just because nodes are anatomically close does not automatically impart functional similarity; the opposite also holds true.
The classification used here is an amalgum of the various systems and appears the most functionally useful, each group having distinct afferents and anatomical location. It also has the benefit of a student-friendly acronym.
- Breast cancer:
- The first site of metastasis
- Vital in staging
- May be a site of metastasis or spread in malignant tumours or infections of the upper limb.
- ↑ Clinically Oriented Anatomy Fifth Edition. Keith L Moore, Arthur F Dalley ISBN 0781736390
- ↑ Gray's Anatomy - The Lymphatics of the Upper Extremity
- ↑ Misnik VP. The anatomy and topography of the human axillary lymph nodes. Arkhiv anatomii, gistologii i émbriologii. 1975 Jun; 69(7):40-5.
- ↑ Misnik WP. Sex and age changes of the axillary lymphatic nodes in adult people (author's transl). Anatomischer Anzeiger. 1980; 147(1):100-6.