Pectoral And Axillary Region

Front 1

Osteology of Pectoral Region: what bones?

Back 1

Clavicles, sternum (manubrium, body, xiphoid), ribs, scapula

Front 2

Pectoral Ribs/region

Back 2

Do not need to identify
They articulate with sternum and vertebrae
Ribs 1, 2, 11, 12 are atypical
Ribs 1-7 are true vertebrocostal ribs
Ribs 8-10 are false ribs (attach to cartilage of other ribs)
Ribs 11-12 are floating

Front 3

Sternum: components

Back 3

Made of manubrium, body, and xiphod

Xiphoid process is the last to fuse and sometimes is absent from individuals

Front 4

Mammary glands: what are they

Back 4

Modified sweat glands

Front 5

Pectoral Fascia

Back 5

The fascial layer that the breast rests on the posterior side of the breast

Front 6

Structure of breast

Back 6

Cutaneous structure, rests on pectoral fascia, retromammary space is potential space between the breast and pectoral fascia
Attaches to the dermis of overlying skin via Cooper's ligaments (suspensory ligaments)
Mammary gland lobules converge on the nipple where there are about 15-20 lactiferous ducts opening surrounded by a pigmented areola

Innervated by intercostal nerves 4-6, could be lateral or anterior from sternal aspect

Front 7

Breast Vasculature

Back 7

BS: mammary branches from anterior intercostal, lateral thoracic, and internal thoracic arteries

The Lateral thoracic artery which is a branch of the axillary artery goes to the lateral portion of the breast

Front 8

Venous Drainage of Breast

Back 8

Mainly Drains to axillary vein via lateral thoracic veins and medial mammary veins

Some drainage goes to the internal thoracic vein via anterior intercostal veins

Front 9

Lymphatic Drainage of Breast Tissue

Back 9

More than 75% of lymph from breast drains through the axillary lymph nodes (pectoral, central, and apical)

Nipple, Areola, lactiferous lobules all drain though the subareolar lymph nodes

The rest goes through the parasternal and abdominal lymph nodes

Front 10

Innervation of Breast Tissue

Back 10

Mainly from anterior and lateral branches of T4-6 of intercostal spinal nerves

Can also get innervation from supraclavicular nerve branches and branches of other intercostal nerves

Front 11

Polymastia, Polythelia, and Mammary Ridge

Back 11

Polymastia-supernumerary breasts
Polythelia-supernumerary nipples
Growth of breast/supernumerary breasts, or supernumerary nipples will occur on the mammary ridge

Front 12

Superficial Fascia of the Pectoral region

Back 12

Within this fascia: there is a msucle called platysma

Along thing, you have the supraclavicular nerves

There are also anterior and lateral branches intercostal nerves on the inferior portion: see picture

Front 13

Pectoral Region: Deltopectoral (clavipectoral triangle)

Back 13

Borders: Deltoid, pectoralis major, middle 1/3 of clavicle

Contains: cephalic vein, deltopectoral lymph nodes, and deltoid branch of thoracoacromial artery (from the axillary artery)

Front 14

Clavipectoral Fascia

Back 14

This fascia invests the subclavius and the pectoralis minor
It attaches to the clavicle and the anterior thoracic wall

The Cephalic vein, thoracoacromial a, and lateral pectgoral nerves pierce it

Becomes suspensory ligament of axilla

Front 15

Muscles of the Pectoral region

Back 15

Pectoralis Major
Pectoralis Minor
Serratus Anterior
Subclavius
All innervated by the ventral rami of spinal nerves via branches of brachial plexus

Front 16

Pectoralis Major

Back 16

PA: medial half/third of clavicle along the anterior surface of sternum and anterior surface of six costal cartilages
DA: Lateral lip of the intertubercular sulcus

Action: Adducts and medially rotates humerus, draws scapula anteriorly and inferiorly via clavicle, clavicular portion flexes humerus, sternal portion can extend humerus while it is in this fixed position

BS: pectoral branches of the thorarcoacromial trunk
Innervation; lateral and medial pectoral nerves (C5, C6 clavicular portion, C7, C8, T1 sternocostal portions)

Front 17

Pecotralis Minor

Back 17

PA: 3-5th ribs, near coastal cartilages
DA: coracoid process of scapula

Action: stabilize the scapula by pulling it anteriorly and inferiorly against the posterior thoracic wall

BS: pectoral branches of thoracoacromial trunk
Innervation: medial pectoral nerve C8 and T1

Front 18

Subclavius

Back 18

PA: junction of 1st rib and it's coastal cartilage
DA: inferior surface of middle 1/3 of clavicle

ACTION: anchor and depresses clavicle

BS: clavicular branches of the thoracoacromial arterial trunk
Innervation: Nerve to Subclavius C5 and C8

Front 19

Serratus Anterior

Back 19

PA: external surfaces of lateral parts of ribs 1-9
DA: anterior surface of medial border of scapula

Action: protract scapula and hold it against the thorax, also some superior rotation of glenoid fossa

BS: Lateral thoracic artery
Innervation: Long Thoracic Nerve (C5, C6, C7)

Front 20

Divisions of Axillary artery

Back 20

Part 1: superior thoracic artery will come off: provide blood to upper structures in thorax

Part 2: thoracoacromial trunk: pectoral, deltoid, acromial, clavicular (usually a branch off of something else like the acromial branch)

Part 3: subscapular artery is typically the largest one off of axillary: cirumflex scapular posteriorly and the thoracodorsal

Front 21

Pectoral Region: venous drainage

Back 21

Drained into the axillary vein (generally follows the course of axilllary artery)
Vein will receive blood from superficial and deep veins of the arm and forearm
There are may deep brachial veins
Superficial veins of arm and forearm: basilic (continues as axillary vein) and cephalic (drains into the axillary before it becomes subclavian vein)

Front 22

Diagrams of basilic and cephalic veins

Back 22

Check diagram

Front 23

Boundaries of Axilla

Back 23

Apex-all the way at the top
Base (a and p folds)
anterior wall
posterior wall
medial wall
lateral wall

Front 24

Apex of axilla: where and what?

Back 24

Apex is made up of clavicle, scapula, and first rib
Look at the picture

Front 25

Base of axilla

Back 25

Skin and superficial fascia
Anterior axillary fold via pec major
Posterior axillary fold via latissimus dorsi and teres major
Chest wall-serratus anterior

Front 26

Anterior wall of axilla

Back 26

Clavicle:
Subclavius
Pect Major
Pect Minor

Front 27

Posterior Wall of Axilla

Back 27

Scapula
Subscapularis
Latissimus Dorsi
Teres Major

Front 28

Lateral Structures of Axilla

Back 28

Intertubercular groove, tendon of long head of biceps, coracobrachialis tendon

Front 29

Contents of Axilla

Back 29

Lots of fat and fascia, Axillary Artery and veins associated with it, Brachial Plexus, lymph nodes, axillary sheath

Front 30

superior view of axillary sheath

Back 30

View image

Front 31

Vasculature of Axilla

Back 31

Axillary artery, cephalic vein, basicilic vein, axillary vein