Breast, Pec, and Axillary Flashcards Preview

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Flashcards in Breast, Pec, and Axillary Deck (29):
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Sternal Angle (Angle of Louis)

Junction of the second rib with sternum at the levels of T4 & T5, and the second d costal cartilages

1

Sections of the sternum

Manubrium, body, Xiphoid process

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Deltoid Fascia

Descends from clavicle, acromion, and scapular spine

Continuous with pectoral fascia anteriorly, infraspinous fascia posteriorly

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Pectoral Fascia

Descends from clavicle and sternum, investing pectoralis major

Becomes axillary fascia laterally

4

Clavicopectoral Fascia

Descends from clavicle. Encloses subclavius and pectoralis minor.

Continuous with axillary fascia

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Axillary Fascia

Continuation of pectoral fascia.

Forms the floor of the axilla.

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Muscles of the pectoral region

- Pectoralis major
- Pectoralis minor
- Subclavius
- Serratus Anterior

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Pectoralis major: Origin, insertion, Innervation, action

Origin: Clavicular head- anterior surface of medial clavicle. Sternocostal end- anterior surface of sternum and superior six costal cartilages.

Insertion: lateral lip of inter tubercular sulcus

Innervation: lateral and medial pectoral nerve.

Action: both adduct and medially rotate humerus. Clavicular head- flexes humerus. Sternocostal head- extends humerus from a flexed position

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Pectoralis minor: origin, insertion, Innervation, action

Origin:Ribs 3-5 near costal cartilages.

Insertion: Coracoid process

Innervation: medial pectoral nerve

Action: stabilizes scapula by drawing it inferiorly against thoracic wall

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Subclavius: Origin, insertion, Innervation, action

Origin: junction of the 1st rib and costal cartilage

Insertion: inferior, middle clavicle

Innervation: nerve to subclavius

Action: anchors and depressed clavicle

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Serratus anterior: Origin, insertion, Innervation, action

Origin: lateral parts of the 1st-8th ribs

Insertion: anterior surface of medial border of scapula

Innervation: log thoracic nerve

Action:
1. Protracts scapula
2. Holds scapula against thoracic wall
3. Superior rotation of scapula.

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Nerves of pectoral region

Median and lateral nerves are named for where they come off of brachial plexus. Not their anatomical position.

- Long Thoracic nerve (C5-C7)(laterally)
- Lateral pectoral nerve (C5-C7)(anteriorly)
-Medial pectoral nerve (C8-T1)(anteriorly)(pierces pec minor to reach pec major)

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Fracture of clavicle

Medial fragment will be elevated due to sternocleidomastoid.

Lateral fragment will be depressed (weight of arm) and addicted and pulled medially (pec major)

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Contents of the axilla: within &outside awry sheath

Within: axillary artery and branches, axillary veins and tributaries, brachial plexus (cords and branches)

Outside: axillary lymph nodes and lymphatic vessels, axillary fat

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Subclavian artery

Arises from brachiocephalic trunk on right side and directly from aorta on left.

Becomes axillary artery at lateral border of first rib

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Axillary artery: Boundaries and parts

Boundaries: superior- lateral border of 1st rib. Inferior- inferior border of teres major (becomes brachial artery)

Divided into 3 parts:
-1st rib and medial border of pec minor
-medial border to lateral border of pec minor
-lateral border of pec minor to inferior border of teres major

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1st part of axillary artery

Between 1st rib and pec minor.
Enclosed within axillary sheath.

Has only 1 branch: superior thoracic artery

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2nd part of Axillary artery

Posterior to pec minor (medial border to lateral border)

2 branches:
- Thoracoacromial artery (divides into 4 branches: Clavicular, Acromial, Deltoid, and Pectoral)
- Lateral thoracic artery

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3rd part of axillary artery

Lateral border of pec minor to inferior border of teres major.

3 branches:
- Posterior circumflex humeral
- Anterior circumflex humeral
- Subscapular (2branches: Circumflex scapular and Thoracodorsal)

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Cephalic vein

Superficial, subcutaneous vein of lateral aspect of upper limb.

Travels through deltopectoral groove, pierces clavipectoral fascia at deltopectoral triangle, feeds into axillary vein.

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Axillary vein

Formed by union of brachial and basilic veins. Becomes subclavian vein at lateral border of 1st rib

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External female breast

Tissue typically extends transversely from lateral border of sternum to midaxillary line and vertically from 2nd to 6th ribs

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Polymastia, polythelia, amastia, gynecomastia

Polymastia: accessory breast
Polythelia: accessory nipples
Amastia: no breast development
Gynecomastia: breast in males

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Vasculature of breast (arteries)

(Veins follow arteries)

Lateral thoracic - gives mammary branches.

Posterior intercostal- gives art branches from lateral cutaneous branches.

Internal thoracic-gives medial mammary branches from anterior intercostal arteries

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Nerves of breast

Anterior and lateral cutaneous branches of 4th to 6th intercostal nerves.

Nipple sits at T4 dermatome

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Lymphatic drainage of breast

From nipple, areola and lobules to subareolar plexus. >75% goes to axillary lymph. Parasternal lymph collects medially. Subdiaphragmatic lymph collects inferiorly.

Important in metastasis of cancer

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Axillary lymph nodes

3 sets of lymphs form base (humeral- lateral, Subscapular- posterior, pectoral- anterior, closest to breast). All drain into central lymph --> drain into apical lymph.

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Presentation of breast cancer

-Invades glandular tissue: large dimples, shortening of suspensory ligaments.

- interference with lymph drainage: lymphadema (excess fluid in subcutaneous space), Peau d'orange (orange peel appearance).

-invades lactiferous ducts (retraction of nipple, shortened ducts)

- invades retro mammary space (breast elevates when muscle contracts)

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Breast cancer surgery

Lumpectomy- usually followed by radiation.

Mastectomy- breast excision if tumor larger than 5cm (simple, modified radical, radical)