2. MUSCLES, MAMMARY GLANDS, CROSS-SECTION
THORACIC WALL
MUSCLES, MAMMARY GLANDS, CROSS-SECTION

3. THORACIC WALL MUSCLES

4. Surface Muscles (Anterior)
Platysma
Pectoralis major
Pectoralis minor
Subclavius
Serratus anterior
Refer in syllabus:
Table 1, pp 47-49
Figure 13, p 50

6. Surface Muscles (Posterior)
Latissimus dorsi
Trapezius
Rhomboideus major
Rhomboideus minor
Refer in syllabus:
Table I; pp 47-9

7. Deltopectoral Triangle
Boundaries:
Anterior border of the deltoid.
Superior border of the pectoralis major.
Middle third of the clavicle.

8. Deltopectoral Triangle
Contents:
Cephalic vein.
Deltopectoral lymph nodes.
Deltoid branch of the thoracoacromial artery.

9. Clavipectoral Fascia Invests subclavius and pectoralis minor.
Attached to clavicle and anterior thoracic wall.
Pierced by:
Cephalic vein
Thoracoacromial artery
Lateral pectoral nerve
Become suspensory ligament of the axilla.

10. THORACIC WALL STRUCTURE (x.s.)
Refer to Figure 15, p. 60 in syllabus as well as background material on pp

12. MAMMARY GLAND

13. Mammary Glands Modified sweat glands 15-20 lobes
Lobes separated by fibrous septa
Lactiferous duct (1 per lobe)
Lactiferous sinus (ampulla):
Dilation as duct enters nipple

14. Mammary Glands Fibrous tela subcutanea: Fatty tela subcutanea:
Connective tissue layer surrounding the entire gland.
Fatty tela subcutanea:
Adipose tissue deep to fibrous layer.
Suspensory ligament of Cooper:
Bundles of collagen fibers in dermis and hypodermis.

15. Mammary Glands
Breast extends from 2nd-3rd rib superiorly to 6th-7th costal cartilage inferiorly.
Extends from lateral border of sternum to beyond the anterior axillary fold.

16. Mammary Glands Retromammary space: Sinus mammarumis:
Space between the gland and the pectoralis major muscle.
Sinus mammarumis:
Space between the two glands.

17. Mammary Gland Arteries
Anterior perforating arteries:
From internal thoracic artery
To medial part of gland
Medial mammary rami:
From 2nd - 4th anterior perforating arteries
To deep medial part of gland

18. Mammary Gland Arteries
Lateral mammary artery:
From lateral thoracic artery.
To inferior part of gland.
Lateral mammary rami:
From lateral cutaneous branches of intercostal arteries.
To lateral part of the gland.

19. Mammary Gland Veins
Superficial and deep venous plexuses drain into internal thoracic, lateral thoracic, and intercostal veins.

20. Mammary Gland Nerves Lateral mammary nerve:
T2-T6
Anterior branch of lateral cutaneous branch of intercostal nerves.
Medial mammary nerve:
Lateral branch of anterior cutaneous branch of intercostal nerves.

21. Mammary Gland Lymphatics
Perilobular and interlobular lymphatic vessels:
Into:
Subareolar plexus:
Lateral lymphatic trunk:
From lateral and superior gland
Medial lymphatic trunk:
From medial and inferior gland

22. Mammary Gland Lymphatics
Lateral lymphatic trunk and Medial lymphatic trunk:
Into:
Pectoral group of axillary lymph nodes:
Subclavian lymphatic channels

23. Mammary Gland Lymphatics
Accessory lymphatic drainage:
Periphery of gland drains into apical group of axillary nodes and follows thoracoacromial trunk.
Circumareolar channels drain into sternal chain.

24. THORACIC WALL LYMPHATICS

25. Lymphatic Drainage Subareolar plexus of nodes Axillary lymph nodes:
Receive from:
Superficial tissues, skin, breast, extrinsic limb muscles.
Include:
Pectoral group
Lateral group
Apical group
Subscapular group

26. Lymphatic Drainage Infraclavicular nodes Parasternal nodes
Abdominal nodes

27. MECHANICS OF RESPIRATION

28. Inspiration: “Bucket Handle”
Involves contraction of intercostal muscles
Results in raising of ribs
Results in an increase in the lateral dimensions of the thoracic cage.

29. Inspiration: “Pump Handle”
Results from raising of sternum
Results in increase in anteroposterior dimensions of thoracic cage

30. Abdominal Breathing Results from lowering of diaphragm:
Phrenic nerve
Necessary when:
Infant
Costal cartilages are calcified

31. Expiration
Mostly passive