Axillary lymph nodes

From Ganfyd

Jump to: navigation, search
Axillary lymph nodes
Axillary lymph nodes.JPG
System: Muscle
Function: Receive lymph from breast, thoracic wall and upper limb
Origin:
Branches:
Insertion:
Arterial supply:
Venous drainage:
Lymphatic drainage: From breast, thoracic wall and upper limb
Innervation:
Vertebral levels:
Search for Axillary lymph nodes in Gray's.


The axillary lymph nodes are a large collection of lymph nodes situated in the axilla.

Contents

Surface anatomy

Normally impalpable, enlarged lymph nodes may be palpated on examination of the axilla.

Shape

There are around 20 lymph nodes located in the axilla (between 15 and 40). They receive lymph from the breast, chest wall, lateral neck and upper limb.

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.

Anatomical classification

Glands of axilla.png

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.

Anterior nodes

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.

Posterior 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.

Infraclavicular 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.

Central nodes

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.

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.

Lateral nodes

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.

Surgical classification

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.

Sentinel node

A sentinel node is the first node to drain from a particular area. In breast cancer, it refers to the first node to drain from that portion of the breast. This is usually an anterior node.

Afferent vessels

Efferent vessels

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[1]) whilst others blend these with apical group (e.g. the original Gray's Anatomy[2], which many other sources copy). Misnik[3] 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[4]. 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.

Clinical Relevance

  • 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.

See Also

References

Personal tools