Pectoral

1. PECTORAL REGION AND MAMMARY
GLAND
TABLE 3

3. PECTORAL REGION
SURFACE LANDMARKS
• Clavicle
• Jugular Notch
• Sternal Angle – Level of 2nd Rib
• Xiphoid process
• Epigastric fossa – 7th costal cartilage
• Nipple
• Deltopectoral triangle
(infraclavicular fossa)
• Tip of coracoid process
• Acromion

4. CLAVICLE
• Lateral end – Flattened, articulates
with acromion of scapula
• Medial end – quadrangular,
articulates with manubrium of
sternum and 1st costal cartilage
• Shaft – medial 2/3 convex
anteriorly, lateral 1/3 convex
posteriorly
• Inferior end – subclavian groove in
middle 1/3
 Superior surface smoother than
inferior

5. MUSCULAR ATTACHMENTS TO CLAVICLE
Lateral 1/3
• Deltoid - anterior
• Trapezius – posterior
• Conoid tubercle, trapezoid line –
attachment of coracoclavicular
ligament
Medial 2/3
• Pectoralis major – anterior
• Sternocleidomastoid – superior
• Sternohyoid – posterior
• Costoclavicular ligament – inferior
• Subclavius – subclavian groove

6. CLINICALANATOMY
 Fracture of Clavicle
 Cleidocranial Dysostosis

7. STERNUM

8. STERNOCLAVICULAR JOINT
• Synovial joint, saddle shaped
• Occurs between clavicle,
manubrium of sternum and 1st
costal cartilage
• Behaves like ball and socket joint
• Articular cavity separated into
two by articular disc
• Reinforced by 4 ligaments
 Anterior sternoclavicular
 Posterior sternoclavicular
 Interclavicular
 Costoclavicular

9. SUPERFICIAL FASCIA
Consists of:
 Mammary gland
 Moderate amount of fat
 Cutaneous nerves
 Cutaneous branches from internal thoracic and posterior
intercostal arteries
 Platysma

10. CUTANEOUS NERVES AND VESSELS
Nerves
• Medial, intermediate and lateral
supraclavicular nerves
• Anterior and lateral cutaneous
branches of 2nd to 6th intercostal
nerves
• Intercostobrachial nerve
Vessels
 Accompany nerves
• Perforating branches of internal
thoracic artery medially
• Lateral cutaneous branches of
posterior intercostal arteries laterally

11. PECTORAL FASCIA
• Deep fascia covering pectoralis major
• Attachments:
 Superiorly – clavicle
 Anteriorly – sternum
 Superolaterally – infraclavicular fossa
and deltopectoral groove to become
continuous with deltoid fascia
 Inferolaterally – inferolateral border of
pectoralis major to become continuous
with axillary fascia
 Inferiorly – continuous with fascia over
thorax and rectus sheath

12. MUSCLES OF PECTORAL REGION
PECTORALIS MAJOR

13. PECTORALIS MINOR

14. SUBCLAVIUS

15. SERRATUS ANTERIOR

16. CLAVIPECTORAL FASCIA

17. CLAVIPECTORAL FASCIA
• Located deep to clavicular portion of pectoralis major
• Extends from clavicle to axillary fascia
 Superiorly – encloses subclavius
 Inferiorly – encloses pectoralis minor
 Medially – attached to external intercostal muscle
 Laterally – attached to coracoid process
Pierced by:
 Lateral pectoral nerve
 Cephalic vein
 Thoracoacromial vessels
 Lymphatics passing from breast and pectoral region to apical
group of axillary nodes

18. BREAST
LOCATION
Superficial fascia of pectoral region
Base of mammary gland extends:
 Vertically from ribs II to VI
 Transversely from lateral border
of sternum to mid-axillary line

19. AXILLARY TAIL
Axillary tail arises from
superolateral quadrant,
pierces deep fascia and
passes into axilla up to
level of rib III

20. DEEP RELATIONS OF BREAST
The breast lies on:
• Pectoral fascia (deep fascia)
 Retromammary space
 Separates breast from pectoral fascia
 Provides some degree of movement over
underlying structures
• Pectoralis major
• Serratus anterior
• External oblique muscle of the abdomen

21. STRUCTURE OF THE BREAST
The breast is made of 3 parts:
1. Skin
• Nipple
• Areola
2. Parenchyma
• Mammary gland
3. Stroma
• Fibrous stroma
• Fatty stroma

22. SKIN
Consists of:
1. Nipple
 Approx. 4th intercostal space in nulliparous
woman
 Pierced by 15-20 lactiferous ducts
 Free of fat, hair
 Circular and longitudinal smooth muscles to
erect or flatten it
 Innervated by 4th intercostal nerve
2. Areola
 Circular pigmented area of skin around nipple
 Contains modified sebaceous glands
 No hair or fat
 Montgomery’s tubercles appear in pregnancy

23. PARENCHYMA
• The mammary gland consists of
15-20 lobes
• Each lobe is a cluster of alveoli
• Each lobe is drained by a
lactiferous duct
• Lactiferous ducts open
independently onto nipple
• At the base of nipple, each duct
is dilated to form lactiferous
sinus
• Milk gets assembled in
lactiferous sinuses
• The glandular tissue is more
abundant in lactating women,
while in non-lactating women fat
is the abundant component

24. STROMA
Forms the supporting framework of the
gland
Partly fibrous and partly fatty
 Fibrous stroma
Produces septa called suspensory ligaments
of Cooper which:
• Suspend the breast
• Anchor it to pectoral fascia
 Fatty stroma
Main bulk of mammary gland
Not found in areola and nipple

25. NEUROVASCULATURE OF BREAST
ARTERIAL SUPPLY
Lateral:
• Superior thoracic
• Thoraco-acromial
• Lateral thoracic
• Subscapular
Medial:
• Branches of internal
thoracic
 Perforating branches of 2nd to
4th intercostal arteries supply
entire breast

26. VENOUS DRAINAGE
• Form an anastomotic
venous circle around the
nipple, which divides into
superficial and deep sets
• Superficial veins drain into
internal thoracic vein
• Deep veins drain into
axillary and posterior
intercostal veins

27. NERVE SUPPLY

28. LYMPHATIC DRAINAGE
Axillary lymph nodes
 5 groups
 Drain into subclavian nodes
Internal mammary/parasternal nodes
 Lie along thoracic vessels
 Drain into bronchomediastinal trunks
 Drain medial quadrants
 Nipple and areola drain into subareolar
lymphatic plexus
 Skin drains to axillary, inferior deep cervical
and infraclavicular nodes
Other lymph nodes:
• Supraclavicular
• Cephalic (deltopectoral)
• Posterior intercostal
• Subdiaphragmatic and subperitoneal lymph

29. CHANGES IN BREAST
Puberty
Development of breasts is almost equal in both sexes until puberty
Estrogen and other hormones cause faster breast development in females
Pregnancy
In early pregnancy, breast size rapidly increases due to increased parenchymal growth and branching
of ducts
Secretory alveoli start developing at duct terminals and get surrounded by connective tissue
In late pregnancy, alveoli are filled with milk under influence of prolactin
Involution
After lactation ends, secretory alveoli start shrinking, decrease in number and eventually disappear
Post – menopause and aging
Breast size regresses severely due to atrophy of mammary gland caused by low levels of estrogen,
giving the breast a pendulous shape.

30. CLINICAL SIGNIFICANCE
Breast cancer
 Spreads via veins and lymphatics hence malignancy is
common
 Peau d’ orange
 Winged scapula – damage to long thoracic nerve
CONGENITAL ANOMALIES OF THE BREAST
 Ectopic breast
 Polymastia
 Polythelia
 Micromastia
 Macromastia
 Gynecomastia