Breast and muscles of the anterior thoracic wall Flashcards
(22 cards)
Explain the breast
-Accessory organs to reproduction in females but rudimentary in
males
-Occur in the subcutaneous tissue overlying the pectoral muscles
-Prominent region is the nipple with the surrounding pigmented
areola
Where does the roughly circular base lie
Between rib 2 to rib 3 vertically
and the Lateral border of the sternum to
the midaxillary line transversely
Describe the internal structure of the breast
-Mammary gland: contain secretory lobules and ducts (lactation)
-Fibrous connective tissue (suspensory ligament): attach breast to skin and pectoral fascia
also to separate secretory lobules.
How do the secretions of the glands drain?
They drain via a single duct from each gland that converges at the nipple.
What are the mammary glands surrounded by?
They are surrounded by fat and fibrous connective tissue.
What makes up the arterial supply
- Branches of the axillary artery( lateral thoracic artery and Thoracoacromial artery) supply the lateral part of the breast.
- Branches of the internal thoracic artery, supply the medial part of the breast as the medial mammary arteries.
What is the venous drainage of the breast?
- Blood drains mainly to the axillary vein which drains to the subclavian vein.
- Some blood drains to the internal thoracic vein which drains to the brachiocephalic vein which merge to form the superior vena cava.
Explain the lymphatic drainage of the breast.
RIGHT SIDE OF BREAST
-75% Drains to axillary nodes mainly pectoral but may go to interpectoral, deltopectoral, supraclavicular, or inferior deep cervical nodes.
LEFT SIDE OF BREAST
- Drains to parasternal nodes or to the opposite breast
BOTTOM OF BREAST
-Drains to inferior phrenic (abdominal) nodes
What happens when someone gets cancer.
There is a blockage of lymphatic drainage
resulting in excess lymph builds up in
the subcutaneous tissue.
What are the clinical features of lymph build up
-nipple deviation and retraction
-prominent skin between small
dimpled pores (peau d’orange)
i.e orange peel effect)
What are large dimples on the breast caused by.
caused by cancerous invasions
and fibrosis which causes
the suspensory ligaments to
shorten.
How can nipple retraction also occur
Nipple retraction can also occur when
the tumor invades the ducts behind
the nipple, pulling it in
GYNAECOMASTIA
-Development of abnormally large mammary glands in males resulting in
breast enlargement.
-Causes remain uncertain. Generally attributed to hormonal imbalance,
and use of certain drugs.
Name the 2 forms of gynaecomastia
- Adolescent gynaecomastia
- Severe gynaecomastia
Explain the development of the breast
-During the 7th week of IU, a milk line is
evident in the embryo
- The milk line extends from the axilla
(armpit) to the groin.
-The milk line usually disappears
except in the midthoracic segment -
forming the breast tissue.
-In 2-6% of women the milk line persists
and accessory nipples (polythelia) and
fully developed and functioning breasts
(polymastia) may occur along this line.
-Accessory breast tissue is susceptible
to disease processes of the breast.
Describe the pectoralis major
-the anterior surface of
medial half of
clavicle
-the anterior surface of
sternum
-superior six costal cartilages \+ aponeurosis of external oblique muscle
Describe the pectoralis minor
-Medial border and superior
surface of the coracoid process of
scapula
-3rd-5th ribs near their costal
cartilages
SERRATUS ANTERIOR
-External
surfaces of
lateral parts of 1st to 8th/9th ribs
-Anterior surface of
medial border of
scapula
What does the intercostal muscle contain
- External intercostal muscle
- Internal intercostal muscle
- Innermost intercostal muscle
What lies within the costal groove
- intercostal vein
- intercostal artery
- intercostal nerve
all of these are called collateral branches
Explain the transverse thoracic muscle
- Internal surface of costal cartilages 2 to 6
-
POSTERIOR MUSCLES
- Contain the serratus posterior superior
- Contains the serratus posterior inferior
