The Axila Flashcards
Pectoral Region
Clavicles, strenum, ribs, and scapula
Parts of sternum
Manubrium, body, and xiphoid process (one of the last things to turn boney in your 20s)
Types of ribs
Atypical: 1,2 = short, don’t have regular features, shaped funny, and don’t attach at sternum. 11 and 12 = floating, no anterior bone attachments.
True: vertebrocostal. 1-7. Have their own costal cartilage that goes from rib to sternum.
False: 8-10, don’t have own costocartilage attachments, piggyback onto others.
Where are ribs located and where do they articulate
Location: thoracic region
Articulation: sternum and vertebrae
Notches on manubrium
Clavicular notch and jugular notch/suprasternal notch.
What is the manubrium sternal angle?
where the maubrium and the sternum meet. aka manubriosternal joint. Where second rib attaches.
Where do the ribs articulate?
1 - manubrium
2- manubrium sternal angle
3-6 - body of sternum
7 - xiphoid process. 8-10 piggy back here.
Head of rib at vertebrae. Costal cartilage at sternum.
What is the breast, what is it innervated by, where does it rest, where does it attach.
Cutaneous surface.
Modified sweat gland.
Rests on pectoral fascia above pectoralis major.
Retromammary space is potential space between breast and pectoral fascia.
Innervated by intercostal nerves 4-6. (Some supraclavicular nerve innervation.)
Attaches to dermis of overlying skin via suspensory ligaments (Cooper’s ligaments).
15-20 lactiferous ducts open at nipple.
Grow along mammary ridge.
Structure of Breast
Mammary gland lobules –> alveolus –> lactiferous ducts –> lactiferous sinus –> nipple –> areola.
Breast Arteries
Axillary and subclavian arteries = main supply of blood. Lateral thoracic and internal thoracic arteries. All go to mammary branches.
Breast Venous Drainage
To axillary vein via lateral thoracic veins, medial mammary veins. Over 75% goes to axillary lymph nodes.
Superficial Fascia
Consists of: platysma, supraclavicular nerves, anterior & lateral branches of intercostal nerves
Deltopectoral (clavipectoral) triangle
Muscles: deltoid, pectorals major, middle 1/3 of clavicle makes border
Drainage: Cephalic vein and deltopectoral lymph nodes
Blood Supply: deltoid branch of thoracoacromial artery (branch of axillary artery)
Clavipectoral fascia
Invests subclavius and pectoralis minor
Attaches to clavicle and anterior thoracic wall
Cephalic vein, thoracoacromial artery, and lateral pectoral nerves peirce it.
Becomes suspensory ligament of axilla.
Muscles of pectoral region
Pectorals major, subclavius, pectorals minor, serratus anterior
Attachments of pectoralis major
Proximal: anterior surface of medial 1/2 of clavicle and anterior surface of sternum and superior 6 costal cartilages.
Distal: Lateral lip of inter tubercular sulcus (bicipital groove)
Actions of pectoralis major
adducts and medially rotates humerus.
draws scapula anteriorly+inferiorly (via clavicle)
Clavicular portion flexes humerus.
Sternal portion can extend humerus while it is in this fixed position.
Blood supply and innervation for pectoralis major
Blood supply: pectoral branches of thoracoacromial arterial trunk.
Innervation: lateral and medial pectoral nerves. From lateral and medial cord of brachial plexus respectively, not named for anatomical position.
Attachments of pectoralis minor
Proximal: 3rd-5th rib, near costal cartilage
Distal: coracoid process of scapula
Actions of pectoralis minor
Stabilizes scapula by pulling it anteriorly & inferiorly against posterior thoracic wall
Blood supply and innervation for pectoralis minor
Blood supply: pectoral branches of thoracoacromial arteries trunk.
Innervation: usually pierced by medial pectoral nerve.
Attachments of subclavius
Proximal: junction of 1st rib and costal cartilage
Distal: inferior surface of middle 1/3 of clavicle
Actions of subclavius
Anchors and depresses clavicle
Blood supply and innervation for subclavius
Blood supply: clavicular branches of thoracoacromial arterial truck.
Innervation: nerve to subclavius
Attachments of serrates anterior
Proximal: external surfaces of lateral parts of ribs 1-9
Distal: anterior surface of medial border of scapula
Actions of serrates anterior
Protracts scapula, rotates scapula, holds scapula against thorax
Blood supply and innervation for serrates anterior
Blood supply: lateral thoracic artery
Innervation: long thoracic nerve
Arteries that contribute to pectoral, shoulder and axillary region
Subclavian and Axillary
Where doe the subclavian artery become the axillary artery
At the lateral border of first rib
Dorsal scapular artery can arise from ____ or _____
subclavian or transverse arteries
Where doe the dorsal scapular artery run?
Along the vertebral border of the scapula
Part 1 of axillary artery
superior thoracic artery
Part 2 of axillary artery
Thoracoacromial trunk. 4 branches: pectoral, deltoid, acromial, clavicular.
Part 3 of axillary artery
Subscapular artery: circumflex scapular and thoracodorsal. Anterior circumflex humeral
Posterior circumflex humeral
Lateral thoracic
Venous drainage of axillary and pectoral region
Axillary vein
Where does the axillary vein receive blood from?
Deep brachial veins
Superficial veins of the arm and forearm: basilic veins (continues as axillary vein) and cephalic vein (drains into axillary before becoming subclavian vein).
Boundaries of axilla
pyramid shaped space
apex: clavicle, scapula, and 1st rib
base (A&P axillary folds): skin & superficial fascia, anterior axillary fold (pec. major), posterior axillary fold (latissimus dorsi and teres major), and chest wall (serrates anterior)
anterior wall: pec. major and minor. (clavicle and subclavius)
posterior wall: scapula, subscapularis, latissimus dorsi, and teres major
medial wall
lateral wall: intertubercular sulcus (bicipital groove), tendon of long head of biceps, coracobrachialis tendon.
