Pectoral Region, Axillary Walls, and Vessels - VCU eCurriculum

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M1 - Anatomy

Pectoral Region, Axillary Walls, and Vessels

DG Simpson, Ph.D.

VCU Department of Anatomy

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Take Home Messages

• Explain the gross anatomy of the female breast.Lymphatic drainage of the anterior chest wall

• Draw and label the 3 parts of the axillaryartery its branches.

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“The anatomy of the female breast assumes special importance because its

distortion provides the clues for diagnosing neoplastic

disease.”

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Breast Cancer

• Most common cancer for women

• 188,587 new cases of invasive breast cancer/year or 516/day

• 55,700 new cases of in situ cancer of the breast or 152/day

• 40,954 deaths/year-112 per day or about 4.6/hour(40,592 are women 362 men)

CDC 2004

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Female Breast:

Mammary Gland

• Modified Sweat Gland

• Contours established by fat

•15-20 lobes of glandular tissue:Surrounding connective tissue allows the glandular tissue to

expand in pregnancy 6

Inactive Mammary

Active Mammary (Non-lactating)

Mammary has lots of connective tissue that functions to provide

potential space

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Ductograms

A) Postmenopausal. B). Young Women

Notes:

• Glands are functional units not anatomical units

• Piercings: risk of ductal damage, infection can travel to glandular tissue, scarring 8

Female Breast: Glandular tissue

•Lactiferous ducts

•One duct/lobe, each opens separately onto nipple surface

•Deep to Areola ducts become lactiferous sinus

Pectoral Region

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Connective Tissue Septa

•Retinacula cutis-separates adjacent lobes of glandular tissueconnections allow breast to move with skin

•Suspensory Ligaments of Cooper-superior aspect ofconnective tissue septa attach to the overlaying dermis 10

Normal tissue has an uneven, lumpy texture as a result of the

connective tissue septa.

This heterogeneous structure has consequences in imaging

modalities and self breast exam

http://sprojects.mmi.mcgill.ca/mammography/images/anatprofile2.jpg

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Lymphatic Drainage

•Axillary Lymph Nodes- 75% of drainage

•Parasternal Lymph Nodes-deep drainage

•Subcutaneous Lymphatic minor drainage but critical clinical feature

Cross mid-line, anastomose with lymphatics of opposite side, drain to costal margin and axilla of opposite side. Cancer often blocks ducts, contributing to spread 12

Obstruction of Subcutaneous Lymphatics“Orange Peel”

http://www-medlib.med.utah.edu/WebPath/jpeg3/BREST003.jpg

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Carcinoma may grow and retract the retinacula cutis

and/or Coopers ligaments and cause dimpling of the exterior

surface of the breast.

http://www.breast-clinic.co.uk/fig9_puckeringsm.jpg

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Male Breast

•Principally a (ornamental?) landmark

•Occasionally Subject to Neoplastic Disease362 fatal cases in men (CDC 2004)

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Male Breast

Gynecomastia-complication of teen years, hormonal (think steroids) or drug therapy (mass typically ranges from 1-5cm in diameter).

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•Origins from Medial 1/3 of clavicle, Sternum and upper abdominal region

•Insertion on crest of greater tubercle of humerus (lateral lip of bicipital groove)

•Innervation from Medial and Lateral Pectoral nerves

Pectoralis Major

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Pectoralis Major:Three actions

•Clavicular portion flexes arm

•Sternal portion is main adductor of arm

•Medial rotation of arm

During climbing pectoralis major also can draw chest upward and prevents upward displacement of humerus.

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•Lies between the deltoid and pectoralis major and contains the cephalic vein

Deltopectoral Triangle

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•Origins from ribs#3 and #5

•Coracoid process of the scapula, medial surface

• Innervation from medial pectoral nerve

Note: Cannot demonstrate action or

test function of Pectoralis Minor in the living

independent of Pectoralis Major

Pectoralis Minor

*

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•Actions: Depresses shoulder and downwardly

rotates the scapula

Pectoralis Minor

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Lateral Pectoral Nerve(Pectoralis Major)

Passes medial to Pectoralis Minor

Medial Pectoral Nerve(Pectoralis Major & Minor)

Passes throughPectoralis Minor

This naming convention has nothing to do with the course of these nerves and everything to do with where they

come from-stay tuned.

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Subclavius Muscle

•Actions: Depresses and rotates clavicle.

•Shunts clavicle anterior during throwing motions

•Protects the underlying subclavian artery & vein from sharp ends of fractured clavicle

•Innervation from the brachial plexus-subclavius nerve (in the neck-will not see now)

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Axilla:

•Roughly an inverted pyramidal shaped space

•Distinct anterior, posterior, medial and lateral boarders

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Axilla

Boundaries

•Anterior: Pectoralis Major formsthe anterior axillary fold

•Posterior

•Medial

•Lateral

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Axilla

Boundaries

•Anterior: Pectoralis Major

•Posterior: (more than you think) Latissimus dorsi (posterior axillary fold), Teres Major, and Subscapularis

•Medial

•Lateral

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Axilla•Boundaries


•Posterior: Latissimus dorsi (posterior axillary fold), Teres Major, and Subscapularis

•Lateral

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Axilla

Boundaries


•Posterior: Latissimus dorsi, Teres Major and, Subscapularis

•Medial: Serratus anterior and chest wall

•Lateral

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AxillaBoundaries


•Posterior:Subscapularis, Teres Major (posterior axillary fold) and Latissimus dorsi

•Medial:chest wall and Serratus anterior

•Lateral: intertuberculargroove of humerus

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Axillary Vessels

Axillary vein-From the brachial vein at teres major continues as subclavian vein

In today’s dissection, look at these vessels and remove to clarify the

underlying artery

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Axillary artery:

Begins at 1st rib and ends at the lateral border of scapula (TeresMajor), where it becomes the Brachial artery.

Three Main Parts, each with named branches:

•Proximal (1:1)

•Deep (2:2)

•Distal (3:3)This is the hard part of

today’s lecture 32

1:1 Supreme Thoracic1st intercostal space

2:2. Thoracoacromial

2:2. Lateral Thoracic

3:3 Subscapular

3:3 Anterior humeral circumflex

3:3 Posterior humeral circumflex

Axillary Artery

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AxillaAxillary artery

•Proximal

•Deep

•Distal

Proximal (1:1)

Deep (2:2)

Distal (3:3)

Supreme Thoracic

Thoracoacromial Lateral Thoracic

Anterior humeral circumflex

Posterior humeral circumflexSubscapular

•Pectoral

•Deltoid

•Clavicular

•Acromial

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Thoracoacromial trunk

•Pectoral branch

With lateral nerve on inferior surface of Pectoralis major

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•Pectoral branch

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•Pectoral branch

•Deltoid branch,Accompanies cephalicvein in deltopectoralgroove

•Clavicular branch

•Acromial branch

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•Pectoral branch

•Deltoid branch,Accompanies the cephalic vein in deltopectoral groove

•Clavicular branch Superomedially towardthe sternoclavicular joint

•Acromial branch

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•Pectoral branch

•Deltoid branch,Accompanies the cephalic vein in deltopectoral groove

•Clavicular branch

•Acromial branch; may arise from deltoid branch

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Axillary artery:•Proximal

•Deep

•Distal

Proximal

Deep

Distal

Supreme Thoracic




Pectoral

Deltoid

Clavicular

Acromial

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1. Supreme Thoracic

2. Thoracoacromial

2. Lateral Thoracic

3. Anterior humeral circumflex

3. Posterior humeral circumflex

3. Subscapular

Axillary Artery

Circumflex scapular

Thoracodorsal (latissimus dorsi)

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Subscapular

Dorsal Scapular

Circumflex scapular

Suprascapular

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•Proximal

•Deep

•Distal

Proximal

Deep

Distal

Supreme Thoracic




•Pectoral

•Deltoid

•Clavicular

•Acromial

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•Proximal

•Deep

•Distal

Proximal

Deep

Distal

Supreme Thoracic




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•Proximal

•Deep

•Distal

Proximal

Deep

Distal

Supreme Thoracic




•Circumflex scapular

•Thoracodorsal (usually travels with the nerve to latissimus dorsi)

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Break 10 Minutes

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Posterior

•Latissimus dorsi

•Teres Major

•Subscapularis

Pectoral Region, Axillary Walls, and Vessels - VCU eCurriculum

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