Anatomy Flashcards
suspensory ligaments of Cooper ?
> > Multiple fibrous bands termed the suspensory ligaments of Cooper provide structural support and run from the chest wall to the dermis.
clavipectoral fascia ?
> > Located deep to the pectoralis major muscle, the pectoralis minor muscle is enclosed in the clavipectoral fascia, which extends laterally to fuse with the axillary fascia
Levels of Axillary LNs ?
- Level I nodes :
» located lateral to the lateral border of the pectoralis minor muscle. - Level II nodes :
» located posterior to the pectoralis minor muscle
» as well as anterior to the pectoralis minor and posterior to the pectoralis major (Rotter or interpectoral nodes). - Level III nodes :
» located medial to the pectoralis minor muscle and include the subclavicular nodes.
The apex of the axilla is defined by
> > the costoclavicular ligament (Halsted ligament)
> > at which point the axillary vein passes into the thorax and becomes the subclavian vein.
Sappey plexus
> > Specialized lymphatic channels collect under the nipple and areola
> > Lymph flows from the skin to the subareolar plexus and then into the interlobular lymphatics
LNS Drainage
> > 75% is directed into the axillary lymph nodes.
> > A minor amount of the lymphatic flow from the breast goes through the pectoralis muscle and into more medial lymph node groups.
> > Lymphatic drainage also occurs through the internal mammary lymph nodes as the predominant drainage in 5% of patients
> > and as a secondary route in combination with axillary drainage in approximately 20% of patients
the long thoracic nerve
> > Coursing deep and close to the chest wall on the medial side of the axilla
> > also known as the external respiratory nerve of Bell, which innervates the serratus anterior muscle.
> > important for fixing the scapula to the chest wall during adduction of the shoulder and extension of the arm.
> > Division of this nerve may result in the winged scapula
the thoracodorsal nerve
> > innervates the latissimus dorsi muscle.
> > This nerve arises from the posterior cord of the brachial plexus and enters the axillary space under the axillary vein, close to the entrance of the long thoracic nerve.
> > The thoracodorsal nerve crosses the axilla to the medial surface of the latissimus dorsi muscle.
> > Function Loss: Impaired shoulder extension, adduction, and internal rotation
> > Clinical Impairment: Difficulty with movements such as climbing, using crutches, or swimming
The medial pectoral nerve
> > derivation from the medial cord of the brachial plexus, innervates the pectoralis major muscle and lies within a neurovascular bundle that wraps around the lateral border of the pectoralis minor muscle
The pectoral neurovascular bundle is a useful landmark because
> > it indicates the position of the axillary vein
> > which is just cephalad and deep (superior and posterior) to the bundle
Nerves cross the axilla horizontally
- three to five sensory intercostal brachial or brachial cutaneous nerves that cross the axilla horizontally
- supply sensation to the undersurface of the upper inner surface of the arm and skin of the chest wall along the posterior margin of the axilla
> > Preservation of the most superior nerve maintains sensation to the posterior aspect of the upper part of the arm without compromising the axillary dissection in most patients.
> > Taking these nerves with their associated lymphatics may lead to lymphedema of the chest wall
breast is composed of three principal tissue types
(1) glandular epithelium
(2) fibrous stroma and supporting structures
(3) adipose tissue
> > predominant tissues are epithelium and stroma
what causes tethering, which can cause dimpling or subtle deformities on the otherwise smooth surface of the breast.
> > infiltration of Cooper ligaments by carcinoma
The milk-forming glands of the lactating breast ?
> > The acini are the milk-forming glands of the lactating breast and, together with their small efferent ducts or ductules, are known as lobular units or lobules
How ductogram works ?
> > injection of contrast material to duct orifice
> > opacifies the entire ductal tree, from the retroareolar duct to the lobules at the end of the tree.
Role of myoepithelial cells
> > The entire ductal system is lined by epithelial cells, which are surrounded by specialized myoepithelial cells that have contractile properties and serve to propel milk formed in the lobules toward the nipple.
the ducts of the breast are surrounded by a continuous basement membrane containing
laminin
type IV collagen
proteoglycans
