THORACIC WALL MUSCLES, MAMMARY GLANDS, CROSS-SECTION.

THORACIC WALLTHORACIC WALL

MUSCLES, MAMMARY GLANDS, MUSCLES, MAMMARY GLANDS, CROSS-SECTIONCROSS-SECTION

THORACIC WALL THORACIC WALL MUSCLESMUSCLES

Surface Muscles (Anterior)Surface Muscles (Anterior)

PlatysmaPlatysmaPectoralis majorPectoralis majorPectoralis minorPectoralis minorSubclaviusSubclaviusSerratus anteriorSerratus anteriorRefer in syllabus:Refer in syllabus:

Table 1, pp 47-49Table 1, pp 47-49Figure 13, p 50Figure 13, p 50

Surface Muscles (Posterior)Surface Muscles (Posterior)

Latissimus dorsiLatissimus dorsiTrapezius Trapezius Rhomboideus majorRhomboideus majorRhomboideus minorRhomboideus minorRefer in syllabus:Refer in syllabus:

Table I; pp 47-9Table I; pp 47-9

Deltopectoral TriangleDeltopectoral Triangle

Boundaries:Boundaries:Anterior border of the deltoid.Anterior border of the deltoid.

Superior border of the pectoralis major.Superior border of the pectoralis major.

Middle third of the clavicle.Middle third of the clavicle.

Deltopectoral TriangleDeltopectoral Triangle

Contents:Contents:Cephalic vein.Cephalic vein.

Deltopectoral lymph nodes.Deltopectoral lymph nodes.

Deltoid branch of the thoracoacromial Deltoid branch of the thoracoacromial artery.artery.

Clavipectoral FasciaClavipectoral Fascia

Invests subclavius and pectoralis minor.Invests subclavius and pectoralis minor.Attached to clavicle and anterior thoracic Attached to clavicle and anterior thoracic

wall.wall.Pierced by:Pierced by:

Cephalic veinCephalic vein

Thoracoacromial arteryThoracoacromial artery

Lateral pectoral nerveLateral pectoral nerveBecome suspensory ligament of the axilla.Become suspensory ligament of the axilla.

THORACIC WALL THORACIC WALL STRUCTURESTRUCTURE

(x.s.) (x.s.)

Refer to Figure 15, p. 60 in Refer to Figure 15, p. 60 in syllabus as well as background syllabus as well as background

material on pp 58-59.material on pp 58-59.

MAMMARY GLANDMAMMARY GLAND

Mammary GlandsMammary Glands

Modified sweat glandsModified sweat glands15-20 lobes15-20 lobesLobes separated by fibrous septaLobes separated by fibrous septaLactiferous duct (1 per lobe)Lactiferous duct (1 per lobe)Lactiferous sinus (ampulla):Lactiferous sinus (ampulla):

Dilation as duct enters nippleDilation as duct enters nipple

Mammary GlandsMammary Glands

Fibrous tela subcutanea:Fibrous tela subcutanea:Connective tissue layer surrounding the Connective tissue layer surrounding the

entire gland.entire gland.Fatty tela subcutanea:Fatty tela subcutanea:

Adipose tissue deep to fibrous layer.Adipose tissue deep to fibrous layer.Suspensory ligament of Cooper:Suspensory ligament of Cooper:

Bundles of collagen fibers in dermis and Bundles of collagen fibers in dermis and hypodermis.hypodermis.

Mammary GlandsMammary Glands

Breast extends from 2Breast extends from 2ndnd-3-3rdrd rib superiorly to rib superiorly to 66thth-7-7thth costal cartilage inferiorly. costal cartilage inferiorly.

Extends from lateral border of sternum to Extends from lateral border of sternum to beyond the anterior axillary fold.beyond the anterior axillary fold.

Mammary GlandsMammary Glands

Retromammary space:Retromammary space:Space between the gland and the Space between the gland and the

pectoralis pectoralis major muscle.major muscle.Sinus mammarumis:Sinus mammarumis:

Space between the two glands.Space between the two glands.

Mammary Gland ArteriesMammary Gland Arteries

Anterior perforating arteries:Anterior perforating arteries:From internal thoracic arteryFrom internal thoracic artery

To medial part of glandTo medial part of glandMedial mammary rami:Medial mammary rami:

From 2From 2nd nd - 4- 4thth anterior perforating arteries anterior perforating arteries

To deep medial part of glandTo deep medial part of gland

Mammary Gland ArteriesMammary Gland Arteries

Lateral mammary artery:Lateral mammary artery:From lateral thoracic artery.From lateral thoracic artery.

To inferior part of gland.To inferior part of gland.Lateral mammary rami:Lateral mammary rami:

From lateral cutaneous branches of From lateral cutaneous branches of intercostal arteries.intercostal arteries.

To lateral part of the gland.To lateral part of the gland.

Mammary Gland VeinsMammary Gland Veins

Superficial and deep venous plexuses Superficial and deep venous plexuses drain into internal thoracic, lateral thoracic, drain into internal thoracic, lateral thoracic, and intercostal veins.and intercostal veins.

Mammary Gland NervesMammary Gland Nerves

Lateral mammary nerve:Lateral mammary nerve:T2-T6T2-T6

Anterior branch of lateral cutaneous Anterior branch of lateral cutaneous branch of intercostal nerves.branch of intercostal nerves.

Medial mammary nerve:Medial mammary nerve:T2-T6T2-T6

Lateral branch of anterior cutaneous Lateral branch of anterior cutaneous branch of intercostal nerves.branch of intercostal nerves.

Mammary Gland LymphaticsMammary Gland Lymphatics

Perilobular and interlobular lymphatic Perilobular and interlobular lymphatic vessels:vessels:

Into:Into:Subareolar plexus:Subareolar plexus:

Into:Into:Lateral lymphatic trunk:Lateral lymphatic trunk:

From lateral and superior glandFrom lateral and superior glandMedial lymphatic trunk:Medial lymphatic trunk:

From medial and inferior glandFrom medial and inferior gland

Mammary Gland LymphaticsMammary Gland Lymphatics

Lateral lymphatic trunk and Medial Lateral lymphatic trunk and Medial lymphatic trunk:lymphatic trunk:

Into:Into:Pectoral group of axillary lymph nodes:Pectoral group of axillary lymph nodes:

Into:Into:Subclavian lymphatic channelsSubclavian lymphatic channels

Mammary Gland LymphaticsMammary Gland Lymphatics

Accessory lymphatic drainage:Accessory lymphatic drainage:Periphery of gland drains into apical group Periphery of gland drains into apical group

of of axillary nodes and follows thoracoacromial axillary nodes and follows thoracoacromial trunk.trunk.

Circumareolar channels drain into sternal Circumareolar channels drain into sternal chain.chain.

THORACIC WALL THORACIC WALL LYMPHATICSLYMPHATICS

Lymphatic DrainageLymphatic Drainage

Subareolar plexus of nodesSubareolar plexus of nodesAxillary lymph nodes:Axillary lymph nodes:

Receive from:Receive from:Superficial tissues, skin, breast, extrinsic limb Superficial tissues, skin, breast, extrinsic limb

muscles.muscles.

Include:Include:Pectoral groupPectoral group

Lateral groupLateral group

Apical groupApical group

Subscapular groupSubscapular group

Lymphatic DrainageLymphatic Drainage

Infraclavicular nodesInfraclavicular nodesParasternal nodesParasternal nodesAbdominal nodesAbdominal nodes

MECHANICS OF MECHANICS OF RESPIRATIONRESPIRATION

Inspiration: “Bucket Handle”Inspiration: “Bucket Handle”

Involves contraction of intercostal musclesInvolves contraction of intercostal musclesResults in raising of ribsResults in raising of ribsResults in an increase in the lateral Results in an increase in the lateral

dimensions of the thoracic cage.dimensions of the thoracic cage.

Inspiration: “Pump Handle”Inspiration: “Pump Handle”

Results from raising of sternumResults from raising of sternumResults in increase in anteroposterior Results in increase in anteroposterior

dimensions of thoracic cagedimensions of thoracic cage

Abdominal BreathingAbdominal Breathing

Results from lowering of diaphragm:Results from lowering of diaphragm:Phrenic nervePhrenic nerve

Necessary when:Necessary when:InfantInfant

Costal cartilages are calcifiedCostal cartilages are calcified

ExpirationExpiration

Mostly passiveMostly passive