Chapter 3: The Thorax Flashcards
what is the superior thoracic aperature open to?
open to the neck
what is the inferior thoracic aperature closed by?
the diaphragm
what are the flexible walls of the thorax formed by?
the musculoskeletal system (ribs, verts, sternum, muscles)
L and R pleural cavities surrounding lungs and mediastinum
thoracic cavity
*one of the most important functions of the thorax
breathing
what parts of the thoracic region are involved in breathing?
diaphragm
thoracic walls
ribs
provides major change in thoracic volume
diaphragm
changes in lateral and anterior dimensions of thorax during breathing
thoracic walls
what does the thorax house?
houses not only lungs, heart, and great vessels but also much of the liver, stomach, and spleen
- acts as a conduit for structures that pass through the thoracic cavity or connect to structures in the thoracic cavity
- houses the heart
the mediastinum
consists of skeletal and muscle elements
thoracic wall
what does the thoracic wall consist of posteriorly?
12 thoracic vertebrae and intervertebral discs
what does the thoracic wall consist of laterally?
ribs and intercostal muscles
what does the thoracic wall consist of anteriorly?
sternum (manubrium, body of the sternum, xiphoid process)
composed of costal cartilage
Anterior (distal) end of ribs
what do ribs articulate with?
thoracic vertebrae
how many articulations do ribs have with vertebral column?
most have 3
are classified as true, false, and floating
ribs
Bordered by vertebrae T1, medial margin of 1st rib, and manubrium
superior thoracic aperature
what is the plane of the thoracic aperture?
oblique
how do the first ribs slope?
inferiorly
what lies on either side of the entrance to the mediastinum at the aperture?
superior aspects of the pleural cavities
what do structures that pass between the thorax and limb pass over?
the pleural cavity and 1st rib
how do structures that pass to the neck go?
pass more vertically
what is a central line put in?
subclavian vein?
how is the superior thoracic aperture sloped?
Sloped downward so posterior attachment is more superior than the anterior attachment
- Large and expandable, closed by the diaphragm
* hole going into the abdomen
inferior thoracic aperture
how do structures that pass to the abdomen go?
pierce or pass posteriorly to the diaphragm
arise radially from margins and converge into a large central tendon
fibers in the inferior thoracic aperture
what are the skeletal elements that form the boundaries of the inferior thoracic aperture?
- Body of vertebrae TXII posteriorly
- Rib XII and distal end of rib XI posteriorly (floating ribs)
- Distal cartilaginous ends of rib VII-X that unite and form anterolateral border
is inferior to the anterior margin of the inferior thoracic margin
the posterior margin
how is the inferior thoracic aperture tilted?
superiorly
*houses heart and big vessels
mediastinum
- extends from sternum to thoracic vertebrae, from super thoracic aperture to inferior aperture
- most important plane in the body
- A plane through the sternal angle and intervertebral disc of TIV and TV separates the superior and inferior mediastinum
midline partition
what is the inferior mediastinum divided by?
pericardial cavity (middle mediastinum) which surrounds the heart
lies between sternum and pericardium
Anterior mediastinum
lies between the pericardium and the thoracic vertebrae
Posterior mediastinum
Situated on either side of the mediastinum
pleural cavities
What does each lung grow out of during development?
mediastinum
covered by visceral pleura membrane
the lungs
is attached to mediastinum by root (airway, blood vessels, lymphatics, nerves
the lungs
lines the pleural cavities
parietal pleura
exists between lungs and thoracic cavity wall
a potential space
exist from spaces not filled with lung
recesses
extend 2-3 cm into neck
pleural cavities
opens into the root of the neck
superior thoracic aperture
separates the thoracic and abdominal cavities
diaphragm
pierces the central tendon and enters right side of mediastinum
inferior vena cava
exits mediastinum and enters muscular part of diaphragm left of midline
esophagus
passes posteriorly to the diaphragm at midline
aorta
where do structures that pass between the thorax and abdomen go?
pass either through or posterior to the diaphragm
- secretory glands, superficial fascia, and overlying skin
* Found in the pectoral region on each side of thoracic wall
breasts
supply anteromedial parts of breast
Branches from internal thoracic arteries and veins perforate thoracic wall
from medial side of breasts and accompany perforating vessels
lymphatics
vessels and lymphatics drain in axiallary region
from lateral side of breast
carry sensation to skin of breast
Lateral and anterior branches of 4th-6th intercostal nerves
what does the plane in the mediastinum mark?
- Boundary between superior and inferior mediastinum
- Beginning and end of aortic arch
- Site where vena cava pierces pericardium
- Bifurcation of trachea
- Superior limit of upper pulmonary trunk`
enters the right of the heart
deoxygenated blood
where does blood from the left side of the body go?
must be shunted across the midline
how is blood from left side of head, neck and left arm moved across the midline?
the left brachiocephalic vein
drained by the hemiazygous and accessory hemiazygous veins
Most of the left thoracic wall
arise from the aorta and internal thoracic arteries
intercostal branches
run with intercostal vessels
intercostal nerves
arise from anterior rami of thoracic spinal nerves
intercostal nerves
reflect the segmental arrangement of thoracic spinal nerves
Dermatomes of skin
innervates mostly the upper arm
first thoracic spinal nerve
innervated by the spinal nerve of C4
the superior part of trunk
follows contours of ribs
Dermatome of T7-T12
arise from spinal nerves T1-L2
All preganglionic nerve fibers of the sympathetic system
why is the thoracic wall explandable?
due to ribs true joints with other aspects of thoracic wall and shape and orientation of ribs
why does the sternum move forward in inspiration?
Because the posterior attachment of the rib is superior to the anterior attachment
why does the thorax expand laterally during inspiration?
Because the middle part of the rib is below both anterior and posterior attachments
expands the thorax inferiorly during inspiration
the diaphragm
innervated by the phrenic nerve
the diaphragm
arises from the brachial plexus (C3-C5)
phrenic nerve
where does the phrenic nerves pass through?
neck, superior thoracic aperture and into the mediastinum
- External to the anterior thoracic wall
* Anchors and supports the upper limb
pectoral region
found in the superficial compartment anterior to the pectoral muscles
mammary glands
what does the breast consist of?
- 15-20 lactiferous ducts
- Nipple
- Areola
- Well defined suspensory ligaments are continuous with the dermis and support the breast
what is the breast made of mostly in non-lactating women?
fat
what is the breast made of in lactating women?
glandular tissue
what is the lateral arterial supply of the breast?
- axillary
- superior thoracic
- thoraco-acromial
- lateral thoracic
- subscapular
parallels arterial supply in the breasts
venous drainage
what is the innervation of the breast?
branches from 2nd-6th intercostal nerves
what are the lymphatics involved in the breast?
- axillary nodes
* parasternal nodes
enclosed in the clavipectoral fascia
The subclavius and pectoralis minor
- origin is the:
- medial half of clavicle
- anterior surface of sternum
- first 7 costal cartilages
- aponeurosis of external oblique
origin of pectoralis major
insertion is the lateral lip of intertubercular sulcus of humerus
pectoralis major
innervated by medial and lateral pectoral nerves
pectoralis major
function is adduction, medial rotation and flexion of humerus at shoulder joint
pectoralis major
originates at rib 1 at junction between rib and costal cartilage
subclavius
inserts at the groove on inferior surface of middle third of clavicle
subclavius
innervated by nerve to subclavius
subclavius
- functions to:
- pull clavicle medially
- stabilize sternoclavicular joint
- depress tip of shoulder
subclavius
originates at the anterior surface of the 3rd-5th ribs, deep fascia overlying the related intercostal space
pectoralis minor
insertion at the caracoid process of scapula
pectoralis minor
innervated by medial pectoral nerves
pectoralis minor
- functions to:
- depress tip of shoulder
- protracts scapula
pectoralis minor
what is the skeletal framework of the thoracic wall like?
segmented in design
bordered by vertebrae TI, rib 1, manubrium
superior thoracic aperture
bordered by vertebrae TXII, rib XII, end of rib XI, costal margin (see fig 3.20) and xiphoid process of the sternum
inferior thoracic aperture
heart shaped vertebral body, and articulates with ribs
thoracic vertebrae
what facets do thoracic vertebrae have?
most have superior costal facet, inferior costal facet, and transverse costal facets
lack inferior demifacets on vertebral body (only articulate with their own rib)
Vertebrae TI and TX (and often TIX)
articulate only with the heads of their own ribs and lack transverse costal facets
Vertebrae TXI and TXII
- each terminates into a costal cartilage anteriorly
* All attach posteriorly to a thoracic vertebrae
ribs
articulate directly with sternum
first 7 ribs (true ribs)
articulate anteriorly with the costal cartilages of the ribs above
ribs VIII-X
floating ribs
ribs XI and XII
what does the typical rib consist of?
curved shaft with anterior and posterior ends
terminates into costal cartilage
anterior end of rib
- articulates with thoracic vertebrae
* characterized by head, neck, and tubercle
posterior end of rib
somewhat expanded and has 2 articular surfaces separated by a crest
the head of ribs
articulates with vertebrae above
smaller superior facet of head of ribs
articulates with its own vertebrae
larger inferior facet of head or ribs
bends forward at the angle
shaft of ribs
marked by a costal groove
inferior margin of rib
what are the atypical ribs?
- rib I
- rib II
- rib X
- rib XI and XII
flat in horizontal plane with broad inferior and superior surfaces
rib I
flat but tice as long, articulates to vertebrae in usual way
rib II
head has single facet for articulation to its own vertebra only
rib X
short, little curve, no tubercles or necks
ribs XI and XII
Slopes down to manubrium, only articulates with vertebrae TI and therefore only has 1 articular surface
rib I
separates 2 smooth grooves that house the subclavian vein and artery (in rib I)
scalene tubercle
shaft is roughened by muscle and ligament attachment (of rib I)
Anterior and posterior to groove
- forms part of bony framework of thorax and neck
* part of sternum
manubrium
what are the components of the manubrium?
- Jugular notch, articular sites for clavicle and rib 1
* Demifacet for articulation with upper half of anterior end of 2nd costal cartilage
- components:
- demifacet for lower half of 2nd costal cartilage
- articular facets for ribs III-VI
- demifacet for articulation of upper half of 7th costal cartilage
- transverse ridges
body of sternum
- variable in shape, demifacet for articulation with inferior end of 7th costal cartilage
- part of sternum
xiphoid process
what does a typical rib articulate with?
- Bodies of adjacent vertebrae, forming a joint with the head of the rib
- The transverse process of its related vertebrae, forming a costotransverse joint
formed when a rib articulates with the transverse process of its related vertebrae
costotransverse process
*2 synovial joints formed (1 between each other demifacets of adjacent vertebrae)
joint with head of rib
separates the 2 synovial joints at head of rib
intra-articular ligament
surrounded by a single joint capusle
synovial joints at head of rib
- synovial joint
* stabilized by costotransverse, lateral costotransverse, and costotransverse ligaments
costotransverse joint
Joints between upper 7 costal cartilages and sternum
sternal joints
- consists of a fibrocartilagenous connection
* not synovial joint
joint between rib 1 and manubrium
what are kind of joint are the joints of ribs II-VII?
synovial joints
divided into 2 compartments by an intra-articular ligament
joint of rib II
what kind of joints are interchondral joints?
synovial joints
what kind of joints are manubriosternal and xiphisternal joints?
symphyses
lie between adjacent ribs and are filled with muscle
intercostal spaces
lie in the costal groove of the superior rib and lie in the plane of the inner 2 layers of muscle
Intercostal nerves and associated major arteries and veins
often lie superior to the inferior rib
Small collateral branches of the intercostal nerves and vessels
separates parietal pleura from ribs and intercostal space
endothoracic fascia
what are the types of intercostals?
- externals
- internals
- innermost
- 11 pairs
- fibers run obliquely anterioinferiorly
- extend from tubercles of ribs to costal cartilages *extend to costal cartilages via external intercostal membrane
externals (intercostals)
- 11 pairs
- fibers run obliquely posteroinferiorly
- extend from parasternal region to angle of rib posteriorly, where it continues as internal intercostal membrane
internal intercostals
deepest layer of intercostals
innermost
- in the same plane as the innermost intercostals
- spans multiple ribs
- more numerous in the lower regions of the posterior wall
subcostales and transverse thoracis
- found on the deep surface of the anterior thoracic wall
- in the same plane as the innermost intercostals
- lies deep to thoracic vessels and secures them to thoracic wall
transverse thoracis
superior attachment is the inferior margin of the rib above
external intercostal
inferior attachment is the superior margin of the rib below
external intercostal
innervated by intercostal nerves T1-T11
external intercostal, internal intercostal, innermost intercostal
moves the ribs superiorly during inspiration
external intercostal
superior attachment is the lateral edge of costal groove of the rib above
internal intercostal
inferior attachment is the superior margin of the rib below, deep to the attachment of related external intercostal
internal intercostal
moves ribs inferiorly during expiration
internal intercostal
superior attachment is the medial edge of costal groove of rib above
innermost intercostal
inferior attachment is the internal aspect of superior margin of the rib below
innermost intercostal
acts with internal intercostal muscles to move ribs inferiorly during expiration
innermost intercostal
superior attachment is the internal surface of the lower rib
subcostales
inferior attachment is the internal surface of second or third rib below
subcostales
innervated by related intercostal nerves
subcostales and transverse thoracis
may depress the ribs
subcostales
superior attachment is the inferior margins and internal surfaces of costal cartilages of 2nd to 6th ribs
transverse thoracis
inferior attachment is the inferior aspect of deep surface of body of sternum, xiphoid process, costal cartilages of ribs IV-VII
transverse thoracis
depresses costal cartilages
transverse thoracis
arise from aorta and internal thoracic artery respectively, forming basket like blood supply
Posterior and anterior intercostal arteries
what are other important arterial branches?
- supreme intercostal artery
- costocervical trunk
- subclavian
- anterior perforating branches
- collateral branches
- superior epigastric
- musculophrenic
generally parallels arterial supply
venous drainage
what are the exceptions to normal venous drainage?
- azygous
- hemiazygous
- accessory hemiazygou
- left and right superior intercostal veins
drain mainly into lymph nodes associated with intercostal arteries (parasternal nodes), head and neck of ribs (intercostal nodes), and diaphragm (diaphragmatic nodes)
Lymphatics of the thoracic wall
drain into bronchomediastinal trunks
parasternal and upper thorax intercostal nodes
drain into thoracic duct
lower thorax intercostal nodes
interconnect with parasternal nodes
diaphragmatic nodes
what do intercostal nerves provide?
- Somatic motor innervation for intercostal muscles
- Somatic sensory innervation for skin and parietal pleura
- Postganglionic sympathetic fibers to periphery
what do intercostal nerves give rise to when they pass laterally in the intercostal space?
- The lateral cutaneous branch (branches into posterior and anterior branches that innervate the skin
- Anterior cutaneous branch
- Collateral branches run along border of lower rib
innervation mainly by intercostal nerves that arise from anterior rami of spinal nerves T1-T11
innervation of thoracic wall
supplied by cutaneous branches of the supraclavicular branch that descends from the cervical plexus
Sensory information of the skin overlying the upper thoracic wall
contributes to the brachial plexus
anterior ramus of T1
contributes to cutaneous innervation of medial surface of upper arm
Lateral cutaneous of 2nd intercostal nerve (interocostobrachial nerve)
supply muscles, skin, and peritoneum of abdominal wall
Lower intercostal nerves
A thin musculotendinous structure that fills the inferior thoracic aperture
diaphragm
what does the diaphragm attach to?
- xiphoid process
- costal margin
- ends of ribs XI an XII
- median acruate ligament on posterior abdominal wall
- lumbar vertebrae
passes through with esophagus
vagus nerve
passes through with the aorta
thoracic duct
innervated by the phrenic nerve (C3-C5)
diaphragm
- supplied by vessels that arise superiorly and inferiorly
- Pericardiaphrenic and musculophrenic
- superior phrenic arteries
- inferior phrenic artery
diaphragm arterial supply
branches of the internal thoracic artery
Pericardiaphrenic and musculophrenic
arise from lower parts of thoracic aorta
superior phrenic arteries
arise from the abdominal aorta
inferior phrenic artery
brachiocephalic azygous system, abdominal veins (suprarenal and inferior vena cava)
venous drainage of diaphragm
what is the volume of the thoracic cavity changes most by?
contraction (inspiration) and relaxation (expiration) of the diaphragm
why is there a superior anterior movement of the sternum during inspiration?
Because the posterior end of ribs is superior to the anterior end
why does the middle of the shaft of rib move laterally during inspiration?
Because the middle of the shaft is inferior to both anterior and posterior ends
- on either side of mediastinum (medial wall)
* extend superiorly above rib 1 and inferiorly just below the costal margin
pleural cavities
lined with visceral pleura
lungs
*contains a thin layer of serous fluid (lubrication)
potential space
named after the parts of the wall it covers
pleura
- parietal pleura
* Ribs and intercostal paces
costal part
- parietal pleura
* covers diaphragm
diaphragmatic part
- parietal pleura
* covers mediastinum
mediastinal part
- parietal pleura
* covers dome shaped extension into neck
cervical pleura/dome of pleura/pleural cupola
exits the mediastinum on left and right sides and enters each lung at the hilum
the root of the lung
reflects along the root and is continuous with the visceral pleura
mediastinal pleura
continuous with the parietal pleura at the hilum of the lung
visceral pleura
2 layers of parietal pleura become opposed here
at recesses
costal pleura is opposed to mediastinal pleura
Costomediastinal recess
largest, between costal and diaphragmatic pleura
Costodiaphragmatic recess
organs of respiration (gas exchange)
lungs
where Air enters and leaves the lungs
bronchi
enters through pulmonary arteries
deoxygenated blood
leaves through pulmonary veins
oxygenated blood
why are left and right lungs different shapes?
due to the heart protruding more to the left
what do both lungs have?
- base
- apex
- costal surface
- mediastinal surface
- inferior border
- anterior and posterior border
- root
- hilum
- pulmonary ligament
has 3 lobes and 2 fissures
right lung
what are the fissures of the right lung and what do they do?
- oblique and horizontal fissures
* separate the lobes
what are the lobes of the right lung?
inferior, superior and middle lobes
adjacent to the Heart, inferior and superior vena cava, azygous vein, esophagus
medial surface of right lung
project over the top of right lung
right subclavian artery and vein
is the left lung smaller or bigger than the right lung?
smaller
has 2 lobes (superior and inferior) that are separated by oblique fissure
left lung
why is the inferior portion of the medial border of the left lung notched?
because of the hearts projection
projects over the heart
lingula of the left lung
what is the medial surface of the left lung adjacent to?
- heart
- aortic arch
- thoracic aorta
- esophagus
project over the top of the left lung
left subclavian artery and vein
extends from CVI to TIV/V where it bifurcates into left and right main bronchus entering each lung
trachea
held open by C-shaped cartilage rings s
trachea
enters the root of the lungs and through the hilum
each main bronchus
divide into lobar bronchi, each of which supplies a lobe
main bronchi
divide into segmental bronchi which supply bronchopulmonary segments
lobar bronchi
the area of the lung supplied by a segmental bronchus and its accompanying pulmonary artery branch
A bronchopulmonary segment
how many bronchopulmonary segments are there in each lung?
10 in each lung
arise from the pulmonary trunk
right and left pulmonary arteries
carry blood back to the left atrium
inferior and superior pulmonary veins
provide nutritive support to lungs
Bronchial arteries and veins
arise from the thoracic aorta or intercostal arteries
bronchial arteries
drain into pulmonary veins, left atrium, azygous system
bronchial veins
innervated by visceral efferents and afferents distributed through anterior and posterior pulmonary plexus
structures of the lung and visceral pleura
where do the anterior and posterior pulmonary plexuses arise from?
the sympathetic trunks and the vagus nerve
constricts bronchioles
vagus nerve
dilates bronchioles
sympathetic system
drain into tracheobroncial nodes
Superficial, or subpleural, and deep lymphatics of lung
where do the superficial(subpleural) and deep lymphatics of the lung ultimately drain into?
drain into right and left bronchomediastinal trunks
where do the superficial and deep lymphatics of the lungs extend from?
extend from within the lungs through the root into the mediastinum
Broad central partition that separates the 2 pleural cavities
mediastinum
what does the mediastinum contain?
- thymus gland
- pericardial sac
- the heart
- the trachea
- major vessels
- acts as a conduit of:
- esophagus
- thoracic duct
- parts of nervous system as they transverse the thorax on the way to the abdomen
mediastinum
what is the mediastinum bordered by?
- superior thoracic aperture
- inferior thoracic aperture
- bodies of vertebrae
- sternum
- pleural cavities
what is the mediastinum divided into?
- superior mediastinum
- inferior mediastinum
what is the inferior mediastinum divided into?
- anterior mediastinum
- middle mediastinum
- posterior mediastinum
fibroserous sac surrounding heart and root of great vessels consists of 2 components
pericardium
what are the two components of the pericardium?
- fibrous pericardium
- serous pericardium
*tough connective tissue outer layer
fibrous pericardium
thin layer consisting of 2 parts: parietal layer- lines inner surface of fibrous pericardium, visceral layer( epicardium)- adheres to the heart
serous pericardium
contains serous fluid
pericardial cavity
attached to the central tendon of diaphragm and to the sternum via the sternopericardial ligaments
fibrous pericardium
supply the fibrous pericardium as they pas through the thorax
Pericardiophrenic vessels
innervates the diaphragm and passes through and innervates the fibrous pericardium
The phrenic nerve (C3-C5)
where do the reflections of the parietal and visceral layers of pericardium occur?
1 around the arteries and 1 around the veins
reflection formed around the veins
oblique pericardial sinus
reflection that forms posterior to the aorta
transverse pericardial sinus
supplied by branches from the internal thoracic, pericardiacophrenic, musculophrenic, inferior phrenic arteries, and the aorta
pericardium
enter the azygous system, internal thoracic, and superior phrenic veins
Veins that drain the pericardium
innervate the pericardium
- vagus nerve
- sympathetic trunk
- phrenic nerve
what are the 5 sides of the heart?
- base
- diaphragmatic
- anterior (sternocostal)
- right pulmonary
- left pulmonary
- projects forward and downward
- extends deep into the left fifth intercostal space
- part of the heart
apex
directed posteriorly and consists of: the left atrium, small portions of the right atrium, and proximal parts of the great vessels
the base
why is the heart fixed posteriorly to the pericardial wall?
because the great veins enter the posterior side of the heart
consists mostly of the right ventricle and some of the right atrium and left ventricle
anterior surface of the heart
- faces inferiorly and rests on the diaphragm
- consists of the left ventricle and a small portion of the right ventricle
diaphragmatic surface of the heart
faces the left lung and consists of the left ventricle and a portion of the left atrium
The left pulmonary surface
faces the right lung and consists of the right atrium
the right pulmonary surface
external grooves created by the internal separations of the heart chambers
sulci
circles the heart separating the atria from the ventricles and holds the right coronary artery, small cardiac vein, coronary sinus, and circumflex branch of left coronary artery
coronary sulcus
separate the ventricles and contain anterior interventricular artery and great cardiac vein, posterior interventricular artery and middle cardiac vein
Anterior and posterior interventricular sulci
consists of 2 pumps separated by a partition
chambers
pumps deoxygenated blood to the lungs
right pump
pumps oxygenated blood to the body
left pump
consists of an atrium and ventricle
each pump
bigger due to more force being required
left ventricle
enters the right atrium
blood returning to the heart
returns blood from head, neck, and arms
superior vena cava
returns blood from thorax, abdomen, and lower limbs
inferior vena cava
returns blood from the walls of the heart
coronary sinus
- opens into right ventricle
* part of right atrium
Right atrioventricular orifice
external vertical groove between superior and inferior vena cava
Sulcus terminalis cordis
internal division between superior and inferior vena cava
crista terminalis
posterior to the crista where venae cavae empty
sinus of venae cavae
ear like extension of atrium
right auricle
the space anterior to the crista, embryonic primitive atrium
atrium proper
ridges that fan out from crista like “teeth of a comb”
Musculi pectinati
vessels of the right atrium
- superior vena cava
- inferior vena cava
- coronary sinus
what are the structures of the right atrium?
- Right atrioventricular orifice
- Sulcus terminalis cordis
- crista terminalis
- sinus of venae cavae
- right auricle
- atrium proper
- musculi pectinati
receives blood from cardiac veins
Opening of the coronary sinus
associated with opening of coronary sinus
valve of coronary sinus
receives blood from inferior vena cava
Opening of inferior vena cava
associated with opening of inferior vena cava
valve of inferior vena cava
separates right and left atria
interatrial septum
marks location of embryonic foramen ovale
fossa ovalis
border of the fossa ovalis
limbus fossa ovalis
openings from numerous small cardiac veins that empty directly into the right atrium
Foramina of the venae cordis minimae
what happens when the tricuspid valve opens?
blood flows into right ventricle
what are the 3 papillary muscles?
- anterior (largest)
- posterior
- septal (smallest)
muscular ridges in right ventricle
trabeculae carnae
form tendon like attachments between the free edges of the cusps of the tricuspid valve and the muscular ventricular wall
chordae tendinae
out flow portion of the right ventricle
the conus arteriosus (infundibulum)
the sites where the cusps of the tricuspid valve are continuous with each other at their bases
commissures
what are the 3 cusps of the right ventricle?
- anterior
- posterior
- septal
- at the apex of the infundibulum
- consists of 3 semilunar cusps
pulmonary valve
has a thickened nodule
the free superior edge of the pulmonary valve
forms a pocket like sinus called pulmonary sinuses
each cusp of the pulmonary valve
what happens after ventricular contraction?
the recoil of blood fills the pulmonary sinus and closes the valve
receives the 4 pulmonary veins
Posterior half or in flow portion of left atrium
continuous with the left auricle and contains musculi pectinate
anterior half of left atrium
what does blood enter the left ventricle through?
the left atrioventricular orifice
prevents back flow into the left atrium
The mitral or left atrioventricular (bicuspid) valve
has trabeculae carneae and papillary muscles (anterior and posterior
the left ventricle
attach to the cusps of the mitral valve via chordae tendinae
papillary muscles
what are the 2 cusps of the mitral valve?
- anterior
- posterior
- separates right and left ventricles
- has a muscular part and a membranous part
interventricular septum
has 3 semilunar cusps with nodules that form aortic sinuses (right, left, and posterior)
aortic valve
originate from the right and left aortic sinuses respectively
Right and left coronary arteries
what happens as blood recoils and fills the aortic sinuses?
it is forced into the coronary arteries
- Dense fibrous connective tissue that forms 4 rings or annulus fibrosus
- inside the heart
cardiac skeleton
what are the 4 rings separated by?
the right and left fibrous trigon
what does the cardiac skeleton provide?
- integrity of openings it surrounds
- attachment for cusps
- separates atrial musculature from ventricular musculature
- electronically isolates the atria from the ventricles
what do coronary arteries arise from?
the aortic sinuses and circle the heart in opposite directions in the coronary sulcus
give off marginal and interventricular branches which converge towards the apex
coronary arteries
what does returning venous blood pass into?
passes into the coronary sinus which drain into the inferior vena cava
originates from the right aortic sinus
the right coronary artery
gives off the sinu-atrial branch
atrial branch
what does the right coronary artery give off?
- atrial branch
- marginal branch
- posterior interventricular branch
arises from the left aortic sinus and moves around the left side of the heart
left coronary artery
what does the left coronary artery give off?
- Anterior interventricular branch
- left marginal branch
- posterior interventricular sulcus
gives rise to the diagonal branch
Anterior interventricular branch
gives rise to the left marginal branch
circumflex
supplied by an enlarged circumflex
posterior interventricular branch
what are the 4 major tributaries that the coronary sinus receives?
- the great
- the middle
- small
- posterior
begins at the apex of the heart and ascends in the anterior interventricular sulcus
Great cardiac vein/anterior interventricular vein
begins at the apex of the heart and ascends in the posterior interventricular sulcus
Middle cardiac vein/posterior interventricular vein
begins in the lower anterior section of the coronary sulcus and may receive the marginal branch
small cardiac vein
lies on the posterior surface of the left ventricle just to the left of the middle cardiac vein
posterior cardiac vein
capable of contracting spontaneously
Musculature of the atria and ventricles
what does the cardiac conduction system consist of?
- sinu atrial node
- atrioventricular node
- atrioventricular bundle
- right/left bundle branch
- cardiac pacemaker
- where the impulse begins, located at the superior end of the crista terminalis
sinu-atrial node
beginning of an elaborate system of conduction, excitation from sinu-atrial node excites the AV node
atrioventricular node
direct continuation of AV node which follows along the lower border of the membranous interventricular septum
atrioventricular bundle
passes on the right of the septum
right bundle branch
passes on the left side of the septum
left bundle branch
passes to the left side of the muscular interventricular septum and descends to the apex
left bundle
what does the left bundle give off?
gives off branches that eventually become continuous with the subendocardial plexus (Purkinje fibers)
spreads impulses throughout the left ventricle
right bundle?
what does the autonomic division of PNS regulate?
- heart rate
- force of contraction
- cardiac output
contribute to the cardiac plexus (both superficial and deep plexuses)
Branches from sympathetic and parasympathetic systems
affect components of the conduction system
Small branches from the cardiac plexus containing both sympathetic and parasympathetic
stimulation of this system results in decreases in heart rate, reduces force contraction, and constricts the coronary arteries
parasympathetic innervation
reach the heart as cardiac branches of the vagus nerve
Preganglionic parasympathetic fibers
stimulation of this system results in increased heart rate and increased force of contraction
sympathetic innervation
reach the cardiac plexus through cardiac nerves from the sympathetic trunk
sympathetic fibers
- Contained within the pericardial sac and covered by the visceral layer of serous pericardium
- found in common sheath with the aorta
- arises from conus ateriosus of the right ventricle
pulmonary trunk
what does the pulmonary trunk split into?
- right pulmonary artery to enter right lung
- left pulmonary artery to enter left lung
contained in the pericardial sac and covered by visceral layer of serous pericardium
ascending aorta
between right and left pulmonary veins
oblique pericardial sinus
contained in the pericardial sac and is covered with serous portion of pericardial sac
Inferior half of superior vena cava
Moving superiorly it enters the mediastinum and becomes the aortic arch
vena cava?
contained in sheath with the pulmonary trunk
vena cava?
enters the fibrous pericardium and is covered with serous portion of pericardial sac, after passing through the diaphragm
inferior vena cava
- covered in serous pericardium except posterior surface
- within pericardial sac
short segment of the pulmonary veins
- found between:
- oblique plain passing through sternal angle
- oblique plane through jugular notch
- right and left lungs
superior mediastinum
continuous with neck above and inferior mediastinum
superior mediastinum
what are the structures found in the superior mediastinum?
- Thymus
- Right and left brachiocephalic veins
- Left superior intercostal vein
- Superior vena cava
- Aortic arch with 3 branches
- Trachea
- Esophagus
- Phrenic nerves
- Vagus nerves
- Left recurrent laryngeal branch of left vagus nerve
- Thoracic duct
- Other small nerves, blood vessels, and lymphatics
Lies immediately posterior to the manubrium
thymus
Can extend into the neck as high as the thyroid and down over the pericardial sac
thymus
- important in early development of the immune system
- found in thymus
bilobed gland
what is the blood supply of the thymus?
Blood supply from branches off internal thoracic artery
where does blood from the thymus drain?
Drains into brachiocephalic or internal thoracic veins
where does the lymphatics of the thymus drain into?
Lymphatics drain into parasternal, tracheobronchial and root of neck
From on both sides at the junction of subclavian and internal jugular veins
Right and Left Brachiocephalic
crosses the midline and joins the right brachiocephalic
Left brachiocephalic
forms at union of left and right brachiocephalic veins
Superior vena cava
where do the right and left brachiocephalic receive blood from?
- vertebral vein
- first posterior intercostal vein
- left superior intecostal vein
- internal thoracic
- thymic
- thyroid veins
Receives blood from 2nd, 3rd, and 4th posterior intercostal veins, bronchial and pericardiophrenic veins
Left Superior Intercostal
Passes over left side of aortic arch and joins left brachiocephalic
Left Superior Intercostal
Inferiorly may connect with accessory hemiazygous (superior hemiazygous
Left Superior Intercostal
found in the superior mediastinum
aortic arch
1st branch of aortic arch
brachiocephalic trunk
what does the brachiocephalic trunk give rise to?
Right subclavian and right common carotid, which supplies the arm and right side of neck/head respectively
2nd branch of aortic arch
left common carotid
supplies left side of neck/head
left common carotid
3rd branch of aortic arch
left subclavian
supplies left arm
left subclavian
vestige of embryonic ductus arteriosus
Ligamentum arteriosum
is in the midline of the superior mediastinum
trachea
posterior to the trachea and anterior to the vertebral column
esophagus
bifurcates at or just inferior to plane of sternal angle
trachea
continues inferiorly in the posterior mediastinum
esophagus
passes along the lateral side of the trachea and passes posteriorly to the root of the lung to reach the esophagus
right vagus nerve
where does the right vagus nerve give off branches to?
- esophagus
- cardiac and pulmonary plexuses
passes between the left common carotid and left subclavian
left vagus nerve
crosses the aortic arch on the way to the posterior side of root of the lung and on to the esophagus
left vagus nerve
where does the left vagus nerve give off branches to?
- esophagus
- cardiac and pulmonary plexuses
gives off left recurrent laryngeal nerve in the superior mediastinum
left vagus nerve
Rises superiorly in a groove between the trachea and esophagus and terminates in the larynx
left recurrent laryngeal nerve
enter the superior mediastinum lateral to the vagus nerve
Left and right phrenic nerves
enter the middle mediastinum and pass on each side of the heart in the pericardial sac
Left and right phrenic nerves
Posterior to the pericardial sac and diaphragm and anterior to vertebral bodies
posterior mediastinum
what structures are found in the posterior mediastinum?
- Esophagus and associated nerve plexuses
- Thoracic aorta and its branches
- Azygous system of veins
- Thoracic duct and associated lymph nodes
- Sympathetic trunks
- Thoracic splanchnic nerves
A muscular tube that passes from pharynx to the stomach
esophagus
Descends along the midline anterior to the vertebral bodies
esophagus
Passes through the esophageal hiatus of the diaphragm
esophagus
where can the esophagus be compressed?
- At the junction of the pharynx
- Where the aorta crosses it
- Where the left primary bronchus crosses it
- at the esophageal hiatus
arise from- thoracic aorta, bronchial arteries, and ascending branches
esophageal arteries
small vessels returning to azygous vein and hemiazygous, and branches of left gastric vein in abdomen
esophageal venous drainage
returns to posterior mediastinal and left gastric nodes
esophageal lymphatic drainage
where do esophageal branches arise from?
esophageal branches
form the esophageal plexus
vagus nerves
forms mainly from the left vagus nerve
anterior vagal trunk
forms mainly from the right vagus nerve
posterior vagal trunk
small vessel to posterior pericardial sac
pericardial branches
usually 2 left bronchial and 1 right bronchial from 3rd posterior intercostal
bronchial branches
4 or 5 vessels from anterior aorta form anastomotic chain
esophageal branches
several branches supply lymph nodes, vessels, nerves, and connective tissues in posterior mediastinum
mediastinal branches
9 pairs branching from posterior aorta that supply lower 9 intercostal spaces
posterior intercostal branches
small vessels from lower part of thoracic aorta that supply superior surface of diaphragm - anastomose with musculophrenic and pericardiophrenic arteries
superior phrenic branches
lowest pair of branches from thoracic aorta
subcostal branches
what does the azygous system consist of?
Azygous vein on the right and hemiazygous and accessory hemiazygous on the left
forms when right ascending lumbar and right subcostal meet
azygous
what does the azygous drain?
- Right superior intercostal vein
- 5th to 11th right intercostal veins
- Hemiazygous/accessory
- Esophageal veins
- Mediastinal veins
- Pericardial veins
- Right bronchial veins
arises at the junction between the left ascending lumbar and left subcostal veins
Hemiazygous (inferior hemiazygous
what does the hemiazygous drain?
- Lowest 4-5 left posterior intercostal veins
- Esophageal veins
- Mediastinal veins
descends on left side from superior portion of posterior mediastinum
Accessory Hemiazygous
The principle channel through which lymph from most of the body enters the venous system
thoracic duct
enlargement formed at the inferior end of the thoracic duct
Cisterna chyli
Joins left jugular and left subclavian veins superiorly
thoracic duct
what does the thoracic duct drain?
- Lymph trunks in abdomen
- Thoracic lymph trunk
- Intercostal lymph trunks
- Posterior mediastinal nodes
- Posterior diaphragmatic nodes
2 parallel cords punctuated with 11 or 12 ganglia
sympathetic trunks
connected to adjacent spinal nerves through white and gray communicantes
ganglia
associated with the splanchnic nerves
Lower 7 ganglia
arises from 5th to 9th ganglia and ends in the celiac ganglia
Greater splanchnic nerve
arises from 9th and 10th and ends in aorticorenal ganglia
Lesser splanchnic nerve
arises from 12th ganglia and ends in renal plexus
Least splanchnic nerve
