Breast and muscles of the anterior thoracic wall

Question 1

Explain the breast

Answer 1

-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

Question 2

Where does the roughly circular base lie

Answer 2

Between rib 2 to rib 3 vertically
and the Lateral border of the sternum to
the midaxillary line transversely

Question 3

Describe the internal structure of the breast

Answer 3

-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.

Question 4

How do the secretions of the glands drain?

Answer 4

They drain via a single duct from each gland that converges at the nipple.

Question 5

What are the mammary glands surrounded by?

Answer 5

They are surrounded by fat and fibrous connective tissue.

Question 6

What makes up the arterial supply

Answer 6

• 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.

Question 7

What is the venous drainage of the breast?

Answer 7

• 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.

Question 8

Explain the lymphatic drainage of the breast.

Answer 8

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

Question 9

What happens when someone gets cancer.

Answer 9

There is a blockage of lymphatic drainage
resulting in excess lymph builds up in
the subcutaneous tissue.

Question 10

What are the clinical features of lymph build up

Answer 10

-nipple deviation and retraction
-prominent skin between small
dimpled pores (peau d’orange)
i.e orange peel effect)

Question 11

What are large dimples on the breast caused by.

Answer 11

caused by cancerous invasions
and fibrosis which causes
the suspensory ligaments to
shorten.

Question 12

How can nipple retraction also occur

Answer 12

Nipple retraction can also occur when
the tumor invades the ducts behind
the nipple, pulling it in

Question 13

GYNAECOMASTIA

Answer 13

-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.

Question 14

Name the 2 forms of gynaecomastia

Answer 14

• Adolescent gynaecomastia

- Severe gynaecomastia

Question 15

Explain the development of the breast

Answer 15

-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.

Question 16

Describe the pectoralis major

Answer 16

-the anterior surface of
medial half of
clavicle

-the anterior surface of
sternum

-superior six costal
cartilages
\+ aponeurosis of
external oblique
muscle

Question 17

Describe the pectoralis minor

Answer 17

-Medial border and superior
surface of the coracoid process of
scapula

-3rd-5th ribs near their costal
cartilages

Question 18

SERRATUS ANTERIOR

Answer 18

-External
surfaces of
lateral parts of 1st to 8th/9th ribs

-Anterior surface of
medial border of
scapula

Question 19

What does the intercostal muscle contain

Answer 19

• External intercostal muscle
• Internal intercostal muscle
• Innermost intercostal muscle

Question 20

What lies within the costal groove

Answer 20

• intercostal vein
• intercostal artery
• intercostal nerve

all of these are called collateral branches

Question 21

Explain the transverse thoracic muscle

Answer 21

• Internal surface of costal cartilages 2 to 6

-

Question 22

POSTERIOR MUSCLES

Answer 22

• Contain the serratus posterior superior

- Contains the serratus posterior inferior