Breast anatomy

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Breast anatomy
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Anatomy

• The mature breast lies cushioned in adipose
  tissue between the subcutaneous fat layer and the
  superficial pectoral fascia .
• Located deep to the pectoralis major muscle, the
  pectoralis minor muscle is enclosed in the
  clavipectoral fascia, which envelops it and
  extends laterally to fuse with the axillary
  fascia.
• Within the loose areolar fat of the axilla are a
  variable number of lymph nodes grouped ,divided
  into three levels
• Level I nodes are located lateral to the lateral
  border of the pectoralis minor muscle.
• Level II nodes are located under the pectoralis
  minor muscle.
• Level III nodes include the subclavicular nodes
  medial to the pectoralis minor muscle and .

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Major nervous structures in the axilla is
required to avoid their sacrifice during surgery

• Coursing close to the chest wall on the medial
  side of the axilla is the long thoracic nerve, or
  the external respiratory nerve of Bell, which
  innervates the serratus anterior muscle. Division
  may result in the winged scapula deformity.
• The second major nerve trunk encountered during
  axillary dissection is the thoracodorsal nerve to
  the latissimus dorsi muscle at the lateral border
  of the axilla. Enters the axillary space under
  the axillary vein, close to the entrance of the
  long thoracic nerve. Its sacrifice leads to loss
  of latissimus function and atrophy of the muscle.

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• A neurovascular bundle (lateral and medial
  wrapping around the lateral border of the
  pectoralis minor muscle innervates the pectoralis
  major muscle. Exposure of the pectoral
  neurovascular bundle is a good landmark,
  indicating the position of the axillary vein just
  above and deep to (superior and posterior) the
  bundle. This neurovascular bundle should be
  preserved during standard axillary dissection.
• The large sensory intercostal brachial or
  brachial cutaneous nerves span the axillary space
  and supply sensation to the undersurface of the
  upper arm and skin of the chest wall, along the
  posterior margin of the axilla. Cutting these
  nerves causes cutaneous anesthesia in these
  areas, which is helpful to emphasize to patients
  prior to axillary dissection. Denervation of the
  areas supplied by these sensory nerves can cause
  chronic and uncomfortable pain syndromes in a
  small percentage of patients.

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Cephalic vein
Lymphatics cross midline
Median cubital v.
Basilic v.
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Suspensory lig. of breast
Lobe of mammary gland
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Suspensory lig. of breast
Lobe of mammary gland
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Clavicular head of pectoralis major m.
Sternocostal head of Pectoralis major m.
Pectoralis major m. fascia
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Pectoralis major m.
Serratus anterior m.
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Clavipectoral fascia
Suspensory lig. of axilla
Pectoralis minor m. fascia
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Thoracoacromial v.
Cephalic v.
Lateral pectoral n.
Medial pectoral n.
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Thoracoacromial a.
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Subclavius m.
Pectoral node III
Pectoral node I
Pectoralis minor m.
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Pectoral node III
Pectoral node II
Pectoral node I
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Brachial plexus
Axillary v.
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Internal mammary a.
Superior thoracic a.
Axillary a.
Lateral thoracic a.
Thoracodorsal a.
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Nerve to serratus anterior
Serratus anterior
Axillary v.
Axillary a.