gross anatomy thorax

what is the thorax

what is the thorax

the area between the neck and abdomen. includes the thoracic cavity and the structures within

what structures does the thorax contain

-the rib cage, thoracic vertebrae and its floor, and the diaphragm

-the primary organs of the respiratory and cardiovascular system

what is the thorax divided into

a central mediastinum, right and left pulmonary cavities

what makes up the thoracic wall

rib cage, skin, breasts, muscles, and fascia covering its anteriolateral aspect, sternum

what are the posterior structures of the thorax called

the back region

what does the rib cage provide

protection of vital organs, resisting of negative internal pressures generated by the recoil of lungs, attachment and support of upper limbs, and attachment for muscles

how many pairs of ribs and costal cartilage

12

how many pairs of thoracic vertabrae

12, and then intervertebral discs (IVD) between them

what are the three types of ribs

true (vertebrocostal)

false (vertebrochondral)

floating (vertebral)

what ribs are true ribs

1-7

what ribs are false ribs

8-10

but also 11 and 12 technically

what ribs are floating ribs

11-12

no anterior attachment

what two classifications of ribs are there

typical and atypical

typical ribs

3-9, includes head, neck, tubercle, and body

atypical ribs

1, 2, 10, 11, 12

why do ribs attach to costal cartilage anteriorly

provide elasticity

what are ribs separated by

intercostal spaces

how are intercostal spaces named

for the rib forming the superior border

what do intercostal spaces contain

muscles, blood vessels, and nerves

what are characteristics of thoracic vertebrae

-bilateral costal facets on bodies, usually superiorly and inferiorly. used for articulation with rib head

-costal facets on transverse process (TVP) for articulation with rib tubercle

-long inferiorly slanting spinous process

-body, attached to pedicles, bilateral TVP, and laminas attached to spinous process

what direction to superior articular facets face

posteriolaterally

what direction to inferior articular facets face

anteriomedially

what are thoracic apertures

the superior and inferior openings of the rib cage

what do thoracic apertures allow communication between

with the neck and arm structures superiorly, and abdominal structures inferiorly

what is the superior thoracic aperture called

thoracic inlet

what is the inferior thoracic aperture

thoracic outlet

what are the accessory muscles of respiration attaching to the rib cage

pectoralis major, pectoralis minor, serratus anterior, and scalenes

what are scalenes

in the neck, attach to manubrium and clavicle to tighten and pull up rib cage during inspiration

what are the true thoracic wall muscles

serratus posterior, levator costarum, intercostals, subcostals, and transverse thoracics

what is the levator costarum

the inner wall of the thoracic cage, used for expiration

what is the diaphragm

primary muscle of inspiration, forms floor of the thoracic cage. separates the thoracic and abdominal viscera

what adjacent structures does fascia invest or attach to

pectoral fascia (bed of breast), clavipectoral fascia (over pectoralis minor), and endothoracic fascia (lines rib cage internally)

what are the nerves of the thoracic wall

intercostal nerves and subcostal nerves

what are intercostal nerves

the anterior primary of the 1st 11 thoracic spinal nerves

where do intercostal nerves run

run between the internal and innermost intercostal muscles. they are lodged in the costal groove on the inferior surface of ribs

what are the intercostal nerves included in

the neurovascular bundle, and the VAN of the intercostal space

what are the subcostal nerves

the anterior primary rami of the 12th thoracic spinal nerve

what is the arterial supply of the vasculature of the thoracic wall

-thoracic aorta through posterior intercostal and subcostal arteries

-subclavian artery through internal thoracic artery and supreme intercostal artery

-axillary artery through superior and lateral thoracic artery

what does the vasculature of the thoracic wall supply

the muscles, skin, and parietal pleura of the thoracic wall, give off branches supplying pectoral muscles and breasts

what do the branches of the posterior intercostal artery supply

spinal cord, vertebral column, and back

what is the venous supply of the vasculature of the thoracic wall

-11 posterior intercostal veins- drain to azygous venous system to the superior vena cava

-anterior intercostal veins- tributaries of internal thoracic veins

-internal thoracic veins

-subcostal veins

what do veins do in relation to their arteries

-generally accompany the same named arteries

-drain the same areas that their corresponding arteries supply

what are breasts

the most prominent superficial structure in the anterior thoracic wall

breast location in relation to pectoral fascia

breasts are anterior to pectoral fascia

what are the breast structures

mammary glands (and their structures), nipple, areola

what are the mammary glands

accessory to reproduction in females, rudimentary in males. they are surrounded by fat. they have an axillary process (tail), lobules, and modified sweat glands

what do lobules produce

parenchyma (functional substance)

where does the parenchyma drain

into the lactiferous ducts leading to a lactiferous sinus where milk accumulates prior to exiting the nipple

what type of control are the modified sweat glands under in the breast

hormonal control

what does the areola surround

the nipple

where is the arterial supply from of the breast

-medial mammary branches and intercostal branches of internal thoracic artery from the subclavian artery

-lateral thoracic and thoracoacromial arteries from the axillary artery

-posterior intercostal arteries from the thoracic aorta

what is the venous drainage of the breast

into the axillary vein by tributaries that accompany the supplying arteries

why is lymphatic drainage of the breast important

due to the metastasis of cancer

how does lymphatic drainage of the breast work

by subareolar lymphatic plexus. 75% drains to pectoral and axillary lymph nodes and the rest drains into parasternal lymph nodes. the lymph eventually enters the right lymphatic duct of the thoracic duct on the left, then enters the R&L venous angles

how many compartments are in the thoracic cavity

3

what are the three compartments of the thoracic cavity? what do they contain?

-R&L pulmonary cavities- contain the lungs and pleurae

-Central Mediastinum- contains the heart, great vessels, thymus, part of the trachea, esophagus, and the lymph nodes

what are the two types of pleurae in the thoracic cavity

visceral (pulmonary) pleura and parietal pleura

what is visceral (pulmonary) pleura

pleura that lines the lung surface

what is the parietal pleura

plerua that lines the pulmonary cavities

what is the parietal pleura specifically named for

named for the parts it touches. ie- ribs, diaphragm, mediastinum

what is pleural cavity

the potential space between the visceral and parietal pleuras

what is the pleural sac

combination of the pleurae, pleural cavity, and pleural sac

what is the essential function of the lungs

respiration and to oxygenate blood

what do the base of the lungs rest on

the diaphragm

when do the lungs descend and ascend

descend- inspiration, ascend- expiration

where is the apex of the lungs

the superior end at the root of the neck

where is the base of the lungs

inferior surface

what are the three surfaces of the lungs

costal, mediastinal, diaphragmatic

what does the anterior border of the left lung have

a deep cardiac notch that shapes the lowest anteroinferior part of the superior lobe into the lingula

how many lobes does the right lung have

3- superior, middle, and inferior

how many lobes does the left lung have

2-superior and inferior

what are the fissures on the right lungs

-right oblique fissure (between the superior and inferior lobes and the middle and inferior lobe)

-horizontal (between middle and superior lobes)

what are the fissures on the left lung

the left oblique fissure

what do the roots of the lung do

attach the lung to the mediastinum

what do the roots of the lung contain

pulmonary artery, superior and inferior pulmonary vein, main bronchus, nerves, and vessels

what is the hilum

area on the mediastinal surface where root structures enter and exit

what is the tracheobronchial tree

the sub-laryngeal airway to the lungs

what is the cartilagenous trunk that splits at the sternal angle

the trachea

what does the trachea split into

the right and left main bronchus, which enter the hilus of each lung respectively

what do the main bronchus (primary) divide into

Lobar Bronchi (3 on right, 2 on left) to supply each lobe

what to lobar bronchi (secondary) divide into

several segmental bronchi (tertiary)

what do segmental bronchi (tertiary) divide into

bronchopulmonary segments

what is the largest subdivision of a lobe

bronchopulmonary segments

what are bronchopulmonary segments separated by

connective tissue. are surgically resectable

what do bronchopulmonary segments further split into

conducting, terminal, and respiratory bronchioles, and and as alveolus (functional gas exchange unit)

pulmonary arteries and the vasculature of the lungs and pleurae

from the heart, carry unoxygenated blood to the lungs. they divide to lobular arteries, to segmental arteries, to alveolar capillary plexus

superior and inferior pulmonary veins and the vasculature of the lungs and pleurae

carry oxygenated blood (via its tributaries, lobar, and segmantal veins) back to the heart

bronchial arteries and the vasculature of the lungs and pleurae

from the thoracic aorta, supply blood to the non respiratory structures of the lungs and visceral pleura

bronchial veins and the vasculature of the lungs and pleurae

drain bronchial arteries and empty into the azygos and hemiazygos veins, that then empty into the SVC

what are the pulmonary lymphatic plexuses

-superficial (subpleural) lymphatic plexuses

-deep lymphatic plexus

what are superficial lymphatic plexuses

deep to visceral pleura. drain the lung tissue and visceral pleura into the bronchopulmonary lymph nodes (near hilum)

what are the deep lymphatic plexus

drain the structures forming the root of the lung (ie the bronchi), into the pulmonary lymph nodes (along the bronchi)

where do bronchopulmonary and pulmonary lymph nodes drain into

the tracheobronchial lymph nodes located superior and inferior to the trachea bifurcation

where do bronchomediastinal lymph trunks end

the right and left venous angles

where do the lungs and pleurae receive nerve innervation from

the anterior and posterior pulmonary plexuses

where are the anterior and posterior pulmonary plexuses located

anterior and posterior to the root of lungs

where to the afferent and efferent parasympathetic fibers of the lungs come from

vagus nerves, joined by branches from upper thoracic sympathetic trunk and cardiac plexus

what do the parasympathetics of the lungs and pleurae cause

bronchoconstriction, vasodilation, and secretomotor to glands

what do the sympathetic fibers of the lungs and pleurae cause

bronchodilation, vasoconstriction, and inhibitory to glands