3. BREAST (MAMMARY GLAND)
GENERAL INTRODUCTION
-it is a modified apocrine sweat gland present in the
superficial fascia of the pectoral region .
-the breast is found in both the sexes, but is
rudimentary in males and is well devloped in
females after puberty .
-on rare occasions,breast of males may get enlarged,
this condition is called as gynecomastia ( probably due to some
hormonal imbalance )
4. -LOCATION
• the breast lies in the superficial fascia of pectoral region .
• it is divided into 4 quadrants :
(1) upper medial
(2) upper lateral
(3) lower medial
(4) lower lateral
do you know that
about 60% of the breast
carcinomas occur in the
upper lateral quandrant .
5. a small extension of the upper lateral quadrant called the axillary tail of spence
( at the level of the 3rd rib ) ,passes through an opening in the deep fascia (axillary
fascia) at the lower border of the pectoralis major muscle and enters the axilla
where it is in the direct contact with the main lymph nodes of the breast i.e. anterior
axillary lymph nodes. this opening is called as the foramen of langer .
• the axillary tail is the site of high percentage of breast tumour .
do you know that carcinoma can also occur in male breast ?
male breast carcinoma accounts about 1% of all carcinomas of the breast.
this fact tends to be overlooked when examining the male patient besides the fact that
carcinoma cells can rapidly metastasize into the thorax through the small amount of
interveining tissue .
SHAPE : the shape may be hemispherical ,conical ,pyriform ,
pendalous or flat .
6. EXTENT OF THE BASE:
-vertically,it extends from the 2nd to the 6th ribs.
-horizontally, it extends from lateral border of
sternum to the mid-axillary line.
- about 2/3 of the breast rests upon the
pectoralis major ,1/3 on the serratus
anterior. at its lower medial quadrant
the gland rests on the aponeurosis
of the external oblique, which separates
it from the rectus abdominis.
7. DEEP RELATIONS:
{following structures are from superficial to deep}
-the breast lies on the deep
fascia(pectoral fascia)
covering anterior aspect of the
pectoralis major.
-MUSCLES:- (1) PECTORALIS MAJOR
(2)SERATUS ANTERIOR
(3)EXTERNAL OBLIQUE ABDOMINUS.
8. pectoral fascia by loose
areolar tissue called the
retromammary space .
- because of the presence of this
loose tissue,the normal breast
can be moved freely over the
pectoralis major muscle.
9. STRUCTURE:
• (1) skin
• (2) stroma
• (3) parenchyma / glandular tisssue / mammary gland proper
• skin – it is supplied by the anterior and lateral branches of 4th,5thand 6th intercostal nerves.
• it covers the mammary gland and presents the following features :
• (a) nipple- it is a conical projection below the center of the
breast at the level of the 4th intercostal space 10 cm
from the midline .
- the nipple is peirced by 15-20 lactiferous ducts.
- it contains circular and longitudnal smooth muscle
fibres which can make the nipple stiff or flatten respectively.
- tiny tubercles on the areola are produced by the underlying areolar glands.
- being richly innervated by sensory nerve endings , the
nipple is most sensitive part of the breast.
10.
11. (B) AREOLA - it is a circular area of pigmented skin
surrounding the base of the nipple .
- it is rich in modified sebaceous glands
particularly at its outer margin .
- these become enlarged during
pregnancy and lactation to form
raised tubercles of montgomery .
- oily secreation of these glands
lubricate the nipple and areola and
prevent them from cracking and drying
during lactation .
12. - apart from sebaceous , the areola also contains
some sweatglands and accessory mammary glands .
- the skin of areola and nipple is devoid of hair and
there is no fat subjacent to it .
- during pregnancy ,the nipple enlarges and the
areola becomesn darker and more extensive as a
result of increased deposits of melanin pigment in
the epidermis.
- below the areola lies the lactiferous sinus where
stored milk is seen
13. DEVELOPMENT
-the epithelial lining of the ducts and acini of the breast is devloped from ectoderm
and the supporting tissue is derived from the mesenchyme.
- the underlying mesenchye proliferates , and the depressed ectodermal thickening
becomes raised to form the nipple .
- at the 5th month , the areola is recognised as a circular pigmented area of skin
around the future nipple.
BREAST ABSCESS
an acute infection of the mammary gland may occur during lactation.
in it , the pathogenic bacteria gain entrance to the breast through a crack in the nipple.
