The layers to the thoracic wall

• epidermis
• dermis
• superficial fascia (where the breast is located)
• deep fascia 
• muscle and bone
• parietal pleura

Special Features of the Breast

•  the breast is a modified sweat gland lying in superficial fascia and overlying pectoralis major, seperated from pectoralis by deep fascia
• extends to the axilla with axilla tails 
• lobules are drained by lactiferous ducts that open on the nipple
• attached to the skin by Cooper's ligaments (suspensory ligaments)
• receives blood supply from internal thoracic, lateral thoracic, thoracoacromial and intercostal arteries
• lymphatic drainage to axillary, parasternal, abdominal, and opposite breast-associated lymph nodes

Pectorial girdle 

attachment for the upper limb; attachment to axial skeleton at the sternoclavicular joint (scapula & clavicle)

Scapula

acromion, coracoid process, and vertebral border

Clavicle

acromial extremity, sternal extremity, origins for pectoralis major, deltoid, & subclavius

The bony features of the humerus

• head
• greater tubercle
• lesser tubercle
• anatomical neck
• surgical neck
• intertubercular sulcus (bicipital groove)
• deltoid tuberosity

Sternum 

Anterior attachment for the ribs (costal cartilages) at sternocostal joints- 3 parts

• Manubrium (handle)
• body or gladiolus (sword)
• xipoid process (dagger-like)

Manubrium (part 1 of sternum)

•  jugular (suprasternal notch)
• clavicular notch 
• sternoclavicular joint
• articulates with rib 1-synchondrosis type joint
• sternal angle (angle of Louis): junction of manubrium and body, rib 2 also articulates here

Body or gladiolus (part 2 of sternum)

articulates with manubrium (manubriumsternal joint), xiphoid process (xiphisternal joint) and ribs 3-6

Xiphoid process (part 3 of sternum)

danger of liver laceration articulates with body. Also articulates with rib 7

Features of the Ribs

• 12 pairs and costal cartilages
• 7 pairs vertebrosternal
• 3 pairs vertebrochondral (8,9,10 they don't go all the way to sternum)
• 2 pairs vertebral (Ribs 11 & 12 little tip of cartilage attached to muscle)
• features of a typical rib (3-10): head articulates with vertebral bodies (costovertebral joints), tubercle with transverse process (costotransverse), shaft features angle (point of greatest curvature) and costal groove
• atypical ribs: rib 1 (shortest) grooves for subclavian artery and vein and anterior scalene tubercle, rib 2 has tuberosity for serratus anterior, ribs 11 and 12 no tubercle, reduced costal cartilage, single facet on head

Intrinsic muscles of the thoracic cage

• levatores costarum
• serratus posterior superior
• serratus posterior inferior
• external intercostal
• internal intercostal
• innermost intercostal
• transverse thoracid

Blood vessels: 

• intercostal arteries
• intercostal veings

• branches of internal thoracic (mammary) from subclavian, and aorta 
• drain to internal thoracic veins or azygos vein

Nerves:

• anterior pirmary rami of thoracic spinal nerves (T12=subcostal) that also communicate with the sympathetic gangliz by way of white and gray rami
• dermatomes T4-nipple, T10-umbilicus

Deltoid

• Attachment
• innervated by axillary nerve, C5-C6
• Actions

Pectoralis Major

•  Attachments:clavicle (clavicular head), sternum and sixth costal cartilage (sternocostal head) to lateral edge of intertubercular sulcus of humerus
• Innervation: lateral pectoral nerve (C5-C7 innervates both heads; medial pectoral nerve (C8-T1) innervates only the sternocostal head. These nerves branch from the laeral and medial cords of brachial plexus.
• Action: adduction and medial rotation of humerus

Pectoralis minor

• Attachments: ribs 3, 4, and 5 to coracoid process of scapula
• Innervation: medial pectoral nerve C8-T1 from medial cord of brachial plexus (also carries fibers of lateral pectoral n.)
• Actions: depression of scapula

Subclavius

• Attachments: from frist rib and muanubrium of stenum to clavicle
• Innervation: never to subclavius C5-C6
• Actions: stabilization of clavicle and sternoclavicular joint; protection for subclavian vessels and brachial plexus in event of fractured clavicle

Serratus anterior

• Attachments: first 8 or 9 ribs to anterior side of medial border of scapula
• Innervation: long thoracic nerve C5-C7 (roots of brachial plexus)
• Actions: protraction of scapula, secures scapula to thoracic cage; (inability to contract produces "scapular winging")