Exam 3 Flashcards
Curvatures of the vertebral column
Primary- concave anteriorly toracic and sacral
Secondary- convex anteriorly cervical and lumbar
Potential abnormal curvatures
Kyphosis
Lordosis
Scoliosis
Scoliosis
Lateral bend
Kyphosis
Exaggerated thoracic curvature (convex)
Lordosis
Exaggerated lumbar curvature (concave)
Movements of the vertebral column
Flexion, extension, lateral bending, rotation
Extrinsic muscles of the thorax and their innervation
Innervation: ventral rami
Superficial layer: trapezius, latissimus dorsi
Intermediate: serratus posterior
Intrinsic muscles of the thorax and innervation
Innervated by dorsal rami
Superficial: splenius capitus
Middle: erector spinae
Deep: transversospinalis
Function of the intrinsic muscles of the thorax
Mostly extension bilaterally, and lateral flexion/rotation unilaterally
Movements of the spine
Bilateral extension and rotation
Longitudinal ligaments anterior and posterior
Allow flexion and extension while keeping vertebrae aligned
Ant- limits extension
post-prevents hyperflexion
Herniated intervertebral disc
Nucleus pulposus is displaced from intervertebral space
Nucleus pulposus
A gel like structure at center. Accounts for much of the strength and flexibility
Annulus fibrosus
Ring shaped disc of fibrous connective tissue that surrounds NP
What direction does the NP move when a disc gets herniated
Posterolaterally
Thorax wall
Jugular notch, manubrium, angle of sternum, body of sternum, xyphoid process of sternum, true ribs 1-7, costal cartilages, false ribs 8-12
Intercostal muscles layers (cross section)
External intercostal muscles
Internal intercostal nerve
Innermost intercostal muscles
Intercostal membranes
External IC membrane (posterior side)
Internal IC membrane (anterior side)
3rd layer of the thorax (internal)
Internal thoracic artery and vein, anterior intercostal arteries and veins and intercostal nerve, internal intercostal muscles, innermost intercostal muscles, transversus thoracis, musculophrenic artery and vein, superior epigastric artery and vein
Intercostal veins
Drain each space and has an anterior and posterior pattern similar to the arteries.
Intercostal arteries
Anterior- upper spaces off internal thoracic artery which comes off subclavian artery
Posterior- off descending aorta, upper two ICS from supreme intercostal artery from Costocervical trunk off subcalvian artery
*Ant ICA branch at about the 6th ICS into superior epigastric and musculophrenic artery *
Where does the internal thoracic artery divide
At the 6th ICS into superior epigastric and musculophrenic artery.
Intercostal nerve
Comes from ventral rami of thoracic spinal nerve (T1-12)
What nerve is T12
Subcostal nerve
Cervical nerves
C1-8
Thoracic nerves
T1-12
Lumbar nerves
L1-5
Sacral nerves
S1-5
Coccygeal nerve
Co1
Intercostal space contents posteriorly
Vein
Aretery
Nerve
What happens if you lacerate an artery off an area close to the aorta
You bleed out
Inspiration
Increases volume and diameter of thoracic cavity, draws air into lungs
Muscle contractions during inspiration
Contraction of the diaphragm increases vertical dimension and contraction of the intercostal muscles increases transverse and ant-post dimension
Muscles movements during expiration
Relaxation of intercostal muscles and thoracic diaphragm, intraabdominal pressure decreases, allows for the elastic recoil of the lungs
Pulmonary cavities
2 individual compartments containing lungs and pleurae
Mediastinum
1 central compartment containing all other thoracic structures. Separates pulmonary cavities from each other
Parietal pleura
Lines the inner surface of each pulmonary cavity. Can be dissected away form peripheral structures.
Visceral pleura
Completely invests lungs. Cannot be dissected away and gives lungs a shiny look
Pleural cavity
Potential space between parietal and visceral pleurae. Pleurae are continuous with each other at the root of the lung. It contained serous fluid that lubricates pleural linings and provides surface tension.
What keeps lungs in contact with the thoracic walls as they expand
The surface tension created by the serous fluid in the pleural cavity
Subdivisions of the parietal pleura
Cervical- covers area of apex of lung
Costal-lines internal surface of ribs and intercostal spaces
Diaphragmatic-cover the superior surface of the diaphragm on either side of the mediastinum
Mediastinal- covers both sides of the mediastinum
Subpleural membrane
Strengthens cervical pleura
Pulmonary ligament
Double layer of mediastinal pleura that extends inferiorly form root of lung
Innervation of the parietal pleura
Costal and peripheral diaphragmatic pleurae is innervated by intercostal nerves. Medisatinal and central diaphragmatic pleurae are innervated by the phrenic nerve.
Visceral pleura innervation
Visceral afferents that run with sympathetics
Location of the Costodiaphragmatic recess
Potential space (recess) inferior in each pleural cavity—accommodate lung during deep inspiration
What forms the costodiaphragmatic recess
Formed by the costal and peripheral diaphragmatic parietal pleurae
Clinical significance of costodiaphragmatic recess
Low point where fluid/blood may accumulate
Location of the Costomediastinal recess
Potential spaces anteriorly in each pleural cavity. Larger on the left due to the heart
What forms the costomediastinal recess
Formed by costal and mediastinal pleurae
Pneumothorax
Entry way of air into the pleural cavity
Open pneumothorax
Wounds open space to lungs, penetrating injury to parietal pleura
Closed pneumothorax
Air leakage form damage to respiratory system itself
Hemothorax
Accumulation of blood in the pleural cavity
Hydrothorax
Accumulation of fluid in pleural cavity
What could a pneumo, hemo, and hydro thorax all result in?
A collapsed lung
Hilum location
Depression on medial surface of the lung
Hilum function
Entrance and exit for root structures
Root formation
Bronchi, pulmonary a and v, bronchial a and v, anterior and posterior pulmonary plexuses, lymphatics
Where does the pulmonary ligament extend form the root
Inferiorly
Apex of the lung
Extends above 1st rib, and is adjacent to the trachea and esophagus and Left common carotid and subclavian artery.
Base of the lung
Sits on diaphragm, opposite of apex.
Costal surface of the lung
Large surface and adjacent to costal pleura
Mediastinal surface of the lung
Concave medial surface and the pulmonary root and ligament are located here
Diaphragmatic surface
Deeper on right to accommodate liver
Right lung shape, lobes, fissures
Larger but shorter and wider
3 lobes; superior, middle, inferior
2 fissures; oblique and horizontal
Pulmonary artery of the right lung location
Anterior to bronchus
Location of pulmonary vein in the right lung
Most anteriorly and inferiorly located structures
Bronchus of the right lung location
Primary/lobar posterior in location
Left lung lobes and fissures
2 lobes; superior and inferior
Fissures; oblique
Cardiac notch
Located in the anterior margin of superior lobe of the left lung
Lingula
Tongue like tail on superior lobe
Impression of the left lung
Cardiac, aortic arch, and thoracic aorta
Pulmonary artery of the left lung
Superior to bronchus in Hilum
Pulmonary vein of left lung
Most anterior in location
Bronchus of left lung
Primary/lobar most posterior in location
RALS
Right pulmonary artery is Anterior to the bronchus Left pulmonary artery is Superior to the bronchus.
Origin of the tracheobronchial tree
Begins at inferior border of cricoid cartilage
Cartilage rings
16-20 C shaped rings, incomplete posteriorly, smooth muscle spans the gap and it abuts the esophagus
Bronchi
pass form trachea to root of lung
Carina
Internal ridge demarcating tracheal bifurcation into right and left bronchi. At the level of sternal angle and sensitive to cough reflex
Right primary bronchus
Wider, shorter, and more vertical. Has 3 lobar branches and is about 2.5 cm long.
Where is an aspirated body most likely to end up
In the right primary bronchus
Left primary bronchus
Narrower, longer, more horizontal. 5 cm long, 2 lobar branches.
How many segmental branches does each bronchi have
8-10
Bronchopulmonary segments
Largest subdivisions of a lobe and there are 8-10 per lung.
Contents of each bronchopulmonary segment
Tertiary (segmental) bronchus, tertiary pulmonary artery, autonomic nerve
If there was a tumor in a bronchopulmonary segment could the lung still function
Yes, the areas not taken out would compensate for the loss of lung tissue where the tumor was
Origin of the pulmonary arteries. What do they carry
Pulmonary trunk. Carry low O2 blood to lungs
Origin of pulmonary veins. What do they carry
Two from each lung. Right and left superior and inferior. Carry high O2 blood to left atrium
Bronchial artery origin and what does is supply
Originates in thoracic aorta. And supply lung itself.
What is contained in the pulmonary cavities
Lungs and pleura
Where is parietal pleura found
Lines pulmonary cavity entirely
Where is the pleural cavity
Between visceral and parietal pleura
What are the different regions of parietal pleura
Cervical, mediastinal, costal, diaphragmatic
What forms the pulmonary ligament
Mediastinal parietal
Where is the costodiaphragmatic recess
Inferior
What innervates costal and peripheral diaphragmatic parietal pleurae
Intercostal nerves
What are the two types of pneumothorax
Open- puncture wound that allows air into pleural cavity
Closed-injury to respiratory organs
Where is the Hilum of the lung
Mediastinal surface
What structures form the root of the lungs
Pulmonary arteries and veins, bronchus, lymphatics
Where is the lingula located
Left lung on the superior lobe
What is found in a bronchopulmonary segment
Tertiary bronchus, tertiary artery
Which arteries carry blood to the lungs for oxygenation
Pulmonary arteries
How many pulmonary veins are there coming back to the heart
- Right and left superior and inferior on each side
Which arteries supply the lung substance
Bronchial arteries
Where is the pericardium
Surrounds heart and proximal part of great vessels
Function of pericardium
Protects and stabilizes heart. Secretes serous fluid (paracardial fluid) to create friction free movement of the heart
Types of pericardium
parietal and visceral
Parietal pericardium
Fibrous and serous
Fibrous parietal pericardium
Outermost layer of pericardium and tough.
Attachments of the parietal fibrous pericardium
Continuous with central tendon of diaphragm and tunica adventitia of IVC. Continuous superiorly with tunica adventitia of great vessels; ascending aorta, pulmonary trunk, SVC, Pulmonary vein.
Serous parietal pericardium
Located in the mesothelial lining on inner surface of
fibrous parietal layer and it Secretes serous fluid
Visceral pericardium
Located Covering on external surface of heart – fatty layer. AKA epicardium. Also serous in nature and can vary in thickness.
What tends to increase the thickness of the visceral pericardium
Obesity
Visceral pericardium point of reflection
Continuous with serous layer
of parietal pericardium at root of great vessels
Where is the pericardial cavity
potential space between parietal and visceral layers of serous pericardium
Contents of pericardial cavity
serous (pericardial) fluid
Functions of the pericardial cavity
facilitates frictionless movement of heart
Pericardial sinuses
Located inside the pericardial cavity
Oblique pericardial sinus
Recess on posterior surface of heart, inferior to pulmonary veins.
Transverse pericardial sinus
Passage posterior to ascending aorta and pulmonary trunk, but anterior to SVC
Significance of transverse pericardial sinus
Used to access great vessels for heart bypass
Where are the pericardial neurovascular structures
Plane between fibrous pericardium and mediastinal pleura
What is the relationship of the pericardial neurovascular structures to the root of the lung
Pass anterior to root of lung
Pericardiacophrenic a
Originates from the internal thoracic artery and runs with the phrenic nerve
Phrenic nerve
Originates from VR C3-5. Runs with pericardiacophrenic artery and vein. Innervates thoracic diaphragm.
Great vessels of the heart
SVC, IVC, Ascending aorta, pulmonary trunk, pulmonary veins,
Formation and draining of the SVC
Union of right and left brachiocephalic veins. Drains all structures superior to thoracic diaphragm except for the heart and lungs.
Where is the SVC
It sits to the right of the aorta in vertical line with IVC as they enter right atrium. Terminates in the right atrium
Formation and drainage of inferior vena cava
Union of right and left common iliac vein and drains lower limbs, abdomen, and abdominal viscera
Where is the IVC
Sits to the right of the aorta and empties into the right atrium
Ascending aorta
Originates from the left ventricle and extends to the beginning of aortic arch. Branches into the right and left coronary artery
Pulmonary trunk
Originate from the right ventricle and is located anterior and to the left of the ascending aorta. Branches into right and left pulmonary artery
Ligamentum ateriosum
Circulatory modification between pulmonary trunk and aorta.
What is the Landmark where left recurrent laryngeal nerve loops around aortic arch
Ligamentum arteriosum
Pulmonary veins
Originate in the lungs and terminate/drain into the left atrium. 4 veins total, two right and two left superior and inferior.
What is the cardiac skeleton composed of
Four fibrous connective tissue rings that surround four heart valves.
Functions of the cardiac skeleton
Keep valves patent and from being overly distended, Attachment point for cusps, Separates atrial and ventricular muscles, Forms electrical insulator, Allows them to contract
independently
Sternocostal surface of the heart
Anterior, formed primarily by right ventricle.
Diaphragmatic (inferior) surface of the heart
Formed primarily by the left ventricle, small part by the right ventricle.
Right pulmonary surface of the heart
Formed primarily by right atrium
Left pulmonary surface of the heart
Formed primarily by left ventricle and creates cardiac impression on the left lung.
Base of the heart
AKA posterior surface—sits opposite of apex and primarily formed by the left atrium. Located where SVC, IVC, adn pulmonary veins enter heart.
Apex of the heart
Formed by the left ventricle. 9-10 cm left of midline at the 5th intercostal space.
Anterior interventricular groove
Located between the right and left ventricles on sternocostal surface. Contents are the anterior interventricular artery and great cardiac vein.
Atrioventricular groove
Located junction between atria and ventricles. Contents are the right and left coronary artery and coronary sinus.
Posterior interventricular groove
Furrow between right adn left ventricles on diaphragmatic surface. Posterior interventricular artery and middle cardiac vein run in this groove.
What vessels enter the right atrium
SVC, IVC and coronary sinus
Right auricle
Extends anteriorly over base of ascending aorta
Pectinate msucles
Found in the anterior wall of the right atrium and auricle.
Sinus venarum
Smooth posterior wall of right atrium. Has openings for SVC, IVC, and coronary sinus.
Crista terminalis—internal
Ridge separating pectinate muscles from sinus venarum (in right atrium)
Sulcus terminalis—external
Shallow external groove that corresponds to crista terminalis
SA node
Deep to epithelium located at junction of SVC and crista terminalis.
AV node
In interatrial septum near opening of coronary sinus.
Coronary sinus
Located in the right atrium posteromedial to IVC
Fossa Ovalis
Oval shaped depression in the interatrial septum of right atrium. Fetal remnant of foramen ovale
Right AV orifice
Entrance of the tricuspid valve. Inferior in right atrium.
Trabeculae carneae
Irregular muscle that lines right and left ventricles.
Conus arteriosus (infindibulum)
Funnel-shaped smooth area leading to the pulmonary trunk.
Tricuspid valve
Prevents back flow of blood from right ventricle back intro right atrium.
Chordae tendineae function to
Pass from papillary muscles to cusps. Prevent prolapse of cusps during ventricular contraction.
Papillary muscles
Function to tense the chordae tendineae
Septomarginal trabecula
Interventricular septum to anterior papillary muscle. Gets papillary muscles contracting before ventricular contraction.
Contents of the septomarginal trabecula
Right bundle branch of AV bundle
Pulmonary Semilunar valve
Between right ventricle and pulmonary trunk
Cusps of the pulmonary semilunar valve
Lunule, nodule, sinus. They are the ‘pockets’
Function of pulmonary semilunar valve
Splay towards arterial wall during systole. Valve closes as pulmonary trunk recoils during diastole forcing blood back to heart.
Left atrium
Located posteriorly with four pulmonary veins entering.
Where are pectinate muscle found in the left atrium
Only in the auricle. Left atrium is primarily smooth.
Can you see the fossa ovalis in the left atrium
You may be able to an indentation on the interatrial septum
Left atrioventricular orifice
Bicuspid valve into left ventricle
Muscles of the left ventricle
2-3X thicker than right ventricle and has more trabeculae carneae. Also has papillary muscles.
Bicuspid valve
Left atrioventricular valve and only has 2 cusps
Aortic vestibule
Smooth outflow region leading to aortic semilunar valve
Aortic semilunar valve
Between left ventricle and ascending aorta. 3 cusps—same as pulmonary semilunar valve
Right and left coronary artery
Open an aortic side of valve, in right and left sinuses of cusps respectively.
Interventricular septum
Strong, oblique partition between the ventricles. It has a muscular part and a membranous part. Membranous part sits superiorly and posteriorly to muscular part
Where is a common site of ventricular septal defects
Membranous part of the interventricular septum
Coronary artery
Can be variable. Is under autonomic control and are considered functional end arteries. They do not have anastomoses because they only supply the heart.
Origin of the coronary artery
Ascending aorta superior to aortic semilunar valve. In the left and right sinuses.
When do the coronary arteries fill
Fill during diastole, when backflow of blood fills aortic semilunar valve.
Right coronary artery
Supplies right atrium, right ventricle, posterior left ventricle, part of the IV septum, SA and AV nodes. It is located posterior to the pulmonary trunk in the atrioventricular groove.
Branches of right coronary artery
SA nodal artery, right marginal artery, posterior interventricular artery (this artery can come from circumflex)
Left coronary artery
Supplies left atrium, most of left ventricle, and most of interventricular septum (including AV bundle). It is typically short
Where is the left coronary artery
Lies between left auricle and pulmonary trunk
Branches of the left coronary artery
Circumflex artery, anterior interventricular artery, posterior interventricular artery (less seen branching off LCA).
What artery is the widowmaker
Anterior interventricular artery/ left anterior descending.
Coronary sinus
Receives majority of venous drainage from heart, in atrioventricular groove, drains into right atrium with low O2 blood.
Anterior cardiac vein
Drain directly into the right atrium. Crosses over right coronary artery.
Great cardiac vein
Runs with anterior interventricular artery
Middle cardiac vein
Runs with posterior interventricular artery
Small cardiac vein
Runs with right marginal artery.
Which layers of the pericardium are serous
Serous parietal and visceral pericardium
Where are parietal and visceral pericardium continuous with each other
The great veins
Where is the pericardial cavity found
Between parietal and visceral pericardium
The phrenic nerve and pericardiacophrenic vessels pass posterior to root of the lung. T/F
False. It passes anterior
What forms the superior vena cava
Right and left brachiocephallic veins
Where does the ascending aorta end
Sternoangle/transverse thoracic plane
Where is the Ligamentum arteriosum located
Between PT and aorta.
Where do the pulmonary veins drain? What are they rich in
Left atrium. O2
What are functions of the fibrous skeleton
Electrical insulations, keeps valves open/patent, attachment for myocardium of arteries and ventricles.
Which chamber primarily forms the base of the heart
Left atrium
Where is the coronary sinus located
Atrioventricular groove
Where is pectinate muscle found
Right atrium and left atria in the auricle
What openings are found in the sinus venarum
Coronary sinus, SVC and IVC
Where is the crista terminalis found? What landmark corresponds externally ?
Right atrium between pectinate (anterior) and sinus venarum (posterior). Sulcus venalis
How many papillary muscles are found in the right ventricle
Three
What are the attachment points for the chordae tendineae
Papillary muscles and valve cusps.
How would you identify the septomarginal trabeculae/moderator band
Interventricular septum and anterior papillary muscle in right ventricle
How many cusps does the pulmonary semilunar valve have
3
When do cusps of valve close
During diastole/ventricular filling
The muscular interventricular septum as thick as the wall of the right ventricle. T/F
False. In the left ventricle.
Where is the aortic vestibule
Just before aortic SL valve
How many cusps does the aortic semilunar valve have
3
Where do the right and left coronary arteries run
Atrioventricular groove
Where do the anterior cardiac vein drain
Into right atrium
Which vein runs with the right marginal artery
Small cardiac
Which artery does the great cardiac vein run with
Anterior interventricular
Placenta
Site of O2 and nutrient exchange
Umbilical cord contents
Umbilical vein and umbilical arteries
Umbilical vein
Carries O2 rich blood to IVC via ductus venosus.
What does the blood in the umbilical vein bypass and how
Bypasses the liver via ductus venosus
Foramen ovale
Opening between the right and left atria where blood is shunted from right to left atrium and it bypasses the lungs. Blood then goes to left ventricle into aorta
Ductus arteriosus
Connects pulmonary trunk to arch of aorta and it bypasses the lungs
Umbilical artery
Branches of internal iliac artery and it returns low O2 blood to placenta for reoxygenation
Patent ductus arteriosus
A ductus arteriosus that doesn’t close
Ductus arteriosus in fetus
Allows blood to pass form pulmonary artery to aorta through this structure and largely bypasses the lungs.
After birth what happens to ductus arteriosus
Normally constricts, and then closes to become ligamentum arteriosum.
Causes of a patent ductus arteriosus
Preterm birth and congenital heart issue
Results of a patent ductus arteriosus
Results in high pressure aortic blood passing through pulmonary artery. Raises BP in pulmonary circulation. Pulmonary hypertension could lead to right sided heart failure.
Foramen ovale in fetus
Passes blood from right atrium to left atrium bypassing the lungs because the mother is oxygenating blood for the fetus.
What happens to the foramen ovalis after birth
Normally closes with pressure changes and becomes fossa ovalis.
What percentage of adults have a small patency of the foramen ovalis
15-25%
What happens with a large patency of the foramen ovale
May overload pulmonary circulation. Hypertrophy of right atrium and ventricle.
Pathway of blood through the heart in the pulmonary circuit
Right atrium—>tricuspid valve—>right ventricle—>pulmonary SL valve—>pulmonary trunk—>pulmonary arteries—>capillary beds of lungs—>pulmonary veins
Pathway of blood through the systemic circuit
Left atrium—>bicuspid valve—>left ventricle—>aortic SL valve—>aorta—>systemic arteries—>capillary beds of body tissues—>systemic veins/vena cava
Blood qualities in the right side of the heart (pulmonary circuit)
O2 poor blood form the body and heart enter the right atrium through the IVC, SVC, anterior cardiac vein and coronary sinus
Blood qualities of blood in the left side of the heart (systemic circulation)
O2 rich blood enters the left side of the heart via the right and left pulmonary veins.
Gas and nutrient exchange of the heart
Coronary artery
Gas and nutrient exchange of body
Systemic artery
Systole
Ventricular shortening and contraction
Diastole
Ventricular elongation and filling
“Lub” sound
First heart sound due to the AV valves closing during systole
“Dub” sound
Second heart sound heard as the semilunar valves close during diastole
Where is the tricuspid valve auscultated
In the 5th intercostal space just left of the sternum
Auscultation of the mitral/bicuspid valve
Auscultated in the 5th intercostal space 9-10cm left of midline
Auscultation of pulmonary semilunar valve
Auscultated in 2nd intercostal space adjacent to left sternum
Where is the aortic semilunar valve auscultated
In the 2nd intercostal space to right of sternum
Valvular heart disease
Increased workload for heart and may be acquired or congenital
Valvular stenosis
Failure of valve to open fully, almost always a chronic process, slows blood flow from the chamber
What can valvular stenosis result in
Turbulence or “heart murmur”
Valvular insufficiency
Failure of valve to close completely, scarring and contraction of cusps or rupture of cords causing them to be overly large or floppy. Can also result in a heart murmur
AV node
Located on interatrial wall near coronary sinus opening. Conveys impulses to AV bundle.
AV bundle
Carries signal through membranous interventricular septum. Passes through cardiac skeleton, electrical link between contraction in atria and ventricles.
Right and left bundle branches
Located in muscular interventricular septum and conveys impulses to purkinje fibers
Cardiac plexus
Conduction system modified by autonomic nervous system. It contains sympathetic, parasympathetic, and visceral afferent nerves also present.
Function of cardiac plexus
Regulates rate and strength of contraction but not required to initiate beat.
Where is the ductus arteriosus and what does it do
Between pulmonary trunk and arch of aorta and it shunts blood from PT to aorta
The umbilical artery carry high O2 content blood black to the fetus. T/F
False. In the umbilical vein
Which chambers of the heart function in the pulmonary circuit? Which valves?
Right atria and right ventricle. Right AV/tricuspid valve and pulmonary semilunar valve
The ventricles shorten and contract during systole. T/F
True
Which heart sound is heard with contraction of the AV valves
“Lub”
What is also known as the “pacemaker of the heart”?
SA node
What carries the impulse from the AV node to the right and left bundle branches
Bundle of hiss
What serves as an electrical insulator between the atria and the ventricles
Cardiac skeleton
Borders of the mediastinum division
Superior thoracic aperature, thoracic diaphragm inferiorly
Divisions of the mediastinum
Superior mediastinum, inferior mediastinum
Superior mediastinum
Above transverse plane between sternal angle and T4-5 IVD.
Inferior mediastinum
Below transverse place between sternal angle and T4-5 IVD. Further divided into 3 regions.
Contents of the superior mediastinum
Mediastinal lymph nodes, thymus, brachiocephallic vein, SVC, arch of aorta, vagus, phrenic, and recurrent laryngeal nerve. Trachea, esophagus, thoracic duct.
Where is the thymus located
Immediately posterior to manubrium, anterosuperior to pericardium.
Function of the thymus
Primary lymphoid organ and the site of T-lymphocyte development.
What happens to the thymus after it undergoes involution after puberty
It becomes fatty tissue
What forms the brachiocephallic vein
The union of the internal jugular and subclavian vein
Which brachiocephallic vein is longer
The left is twice as long as the right
Where does the brachiocephallic vein drain blood from
From the head, neck, and upper extremities
Where do the brachiocephalic veins end
Unite to form the SVC inferiorly
What forms the superior vena cava
Union of the right and left brachiocephalic veins
Azygos vein
SVC receives azygos just superior to entry into pericardial sac. Arch of azygos passes superior to root of right lung.
Where does the SVC terminate
Drains into the right atrium
Aortic arch
Begins at the sternal angle anteriorly and ends at the sternal angle posteriorly.
Branches of the aortic arch
Brachiocephalic trunk, left common carotid, left subclavian artery.
Continuation of aortic arch
Becomes descending thoracic aorta
Origin of trachea
Begins at inferior border of cricoid cartilage.
Location of trachea
Sits anterior to the esophagus and to the right of midline
Trachealis muscle
Smooth muscle that spans the gap posterior. Abuts esophagus.
Where does the trachea terminate
At sternal angle (T4-T5). Not found in posterior mediastinum.
Esophagus
Fibromuscular tube from pharynx to stomach
Where does the esophagus enter the superior mediastinum
Between the trachea and vertebrae
Where does the esophagus enter the posterior mediastinum
Inferior to aortic arch
Right vagus nerve
Is anterior or right subclavian artery and gives rise to right recurrent laryngeal nerve. Passes through superior mediastinum to the right of the trachea.
Left vagus nerve
Located between the left common carotid artery and left subclavian artery. Passes anterolaterally over aortic arch.
Left recurrent laryngeal nerve
Loops posteriorly around aortic arch, behind ligamentum arteriosum.
Both vagus nerves pass..
Posterior to root of lung
Esophageal plexuses
Left vagus nerve-contributes to anterior esophageal plexus
Right vagus nerve- contributes to posterior esophageal plexus
Origin and classification of phrenic nerve
VPR C3-5. Motor and sensory to thoracic diaphragm.
On the right the phrenic nerve
Sits to the right of the right brachiocephallic vein and the SVC
On the left the phrenic nerve
Crosses the arch of the aorta; passes over the L vagus nerve, and the superior intercostal vein
Path of the phrenic nerve
Both pass anterior to root of lung, between mediastinal pleura and parietal pericardium, runs with pericardiacophrenic artery and vein
Boarders of the Inferior mediastinum
Transverse plane between sternal angle and T4-5 IVD. Thoracic diaphragm inferiorly
Three regions of the inferior mediastinum
Anterior, middle, and posterior.
Contents of the anterior inferior mediastinum
Lower part of thymus remnant, internal thoracic vessels, paraphernalia lymph nodes, adipose tissue.
Middle mediastinum contents
Heart, pericardium, root of great vessels, phrenic nerve and pericardiacophrenic artery and vein on fibrous pericardium.
Posterior mediastinum borders
T5-12, posterior to pericardium between pulmonary cavities.
Contents of posterior mediastinum
Descending thoracic aorta, esophagus and esophageal plexus, anterior and posterior fatal trunks, thoracic duct and lymph nodes, azygos system of veins, thoracic sympathetic trunk and splanchnic nerve
Descending thoracic aorta
Descends through thorax on left side of T5-T12 and it displaces esophagus to the right.
Aortic hiatus
T12, behind thoracic diaphragm, descending aorta passes through and becomes abdominal aorta.
Paired visceral branches of descending thoracic aorta
Bronchial artery
Blood supply of esophagus
Esophageal artery from descending thoracic aorta
Location of esophagus
Between trachea and T1-4 vertebrae in superior mediastinum. Posterior to pericardium adjacent to T5-10 in posterior mediastinum.
Esophageal hiatus
At level of T10 opening for esophagus to pass through to go to stomach
What forms the esophageal plexus
Formed by left and right vagal nerve
Anterior vagal trunks
Neurons from left vagus nerve emerging from anterior esophageal plexus. On the anterior surface of esophagus.
Posterior vagal trunk
Neurons from right vagus nerve emerging from posterior esophageal plexus. On posterior surface of esophagus.
What does the thoracic duct look like
Small, thin walled and often beaded die to numerous valves
Location of thoracic duct
Posterior to esophagus, anterior to thoracic vertebrae, between thoracic aorta and azygos veins.
Function of thoracic duct
Drains lymph from entire body except upper right quadrant and inferior lobe of left lung
Cisterna chyle
Origin of thoracic duct in abdomen at L1, enters thorax via aortic hiatus. Around T4 it passes to the left.
Termination of thoracic duct
Typically drains into left venous angle. Junction of left subclavian and left internal jugular vein.
What does azygos mean
Unpaired
Azygos system of veins
Are highly variable and valveless. Drains back, thoracoabdominal walls and mediastinal viscera.
Azygos vein
In posterior mediastinum on right side. Arch of azygos veins superior to root of right lung. Receives blood from right side.
Hemi-azygos veins
In posterior mediastinum on left side inferiorly. Usually crosses over around T9 to drain into azygos vein. Receives blood from lower left side
Accessory hemi-azygos veins
In posterior mediastinum on left side superiorly. Usually crosses over around T8 to drain into azygos veins. May join up with hemiazygos vein and form one vein to drain into azygos. Receives blood from upper left side.
What does the azygos system of veins connect to
Lumbar vein and IVC
Thoracic sympathetic trunk
Series of paravertebral ganglia linked by interganglionic remi
Location of the thoracic sympathetic trunk
Parallel vertebral column bilaterally and are continuous with cervical and lumbar sympathetic trunks.
Thoracic splanchnic nerve
AKA abdominopelvic splanchnic nerve that arises from sympathetic trunk ganglia. Preganglionic sympathetic fibers and they supply viscera inferior to the thoracic diaphragm.
Lesser thoracic splanchnic nerve
T10-T11
Greater thoracic splanchnic nerve
T5-T9
Least thoracic splanchnic nerve
T12
Attachments of the thoracic diaphragm
Xiphoid process, lower 6 ribs and costal cartilages, posterior body wall via arcuate ligaments, vertebrae via crura (left crus-bodies L1-2/3. Right crus-bodies of L1-3/4)
Blood supply of thoracic diaphragm
Musculophrenic artery, superior phrenic artery, inferior phrenic artery.
Thoracic diaphragm posterior abdominal wall attachments
Median arcuate ligaments, medial arcuate ligaments, lateral arcuate ligaments
Caval hiatus
Located in the thoracic diaphragm. Most anterior through central tendon. IVC at T8
Esophageal hiatus
Created by R crus of diaphragm, esophagus at T10, vagal trunks as well.
Aortic hiatus
Most posterior and surrounded by R/L crura. Thoracic aorta at T12. Thoracic duct and azygos vein here as well.
I 8 10 eggs at 12
IVC at T8
T10 esophagus
Aortic at T12
What are the landmarks for the recurrent laryngeal nerve
Behind ligamentum arteriosum
Where are the vagus nerves in relationship to the root of hte lung
Posterior to it
What does the phrenic nerve supply and what are its roots
Diaphragm and C3-5
Which vagus nerve forms the anterior vagal trunk
Left vagus
Where is the thoracic duct located
Posterior to esophagus
Anterior to vertebral column
Sits between aorta and azygos vein
Where does the azygos vein drain
SVC
The sympathetic trunk runs the entire length of the vertebral column bilaterally. T/F
True
Where do the thoracic splanchnic nerve arise
Thoracic sympathetic trunk
Which spinal levels contribute to the greatest thoracic splanchnic nerve
T5-9
What are the attachment points for the diaphragmatic crura
Vertebral bodies
Which arcuate ligament arches over the psoas major muscle
Medials (2)
Three groups cell bodies exist in
Nuclei, ganglia, intramural ganglia or cluster
Cell body #1
In CNS and is Preganglionic, axon is myelinated and synapses with cell body #2
Cell body #2
Postganglionic. In PNS and axon is unmyelinated and travels to the target visceral organ
Dual innervation
Each organ is innervated with sympathetics and parasympathetics. Usually antagonistic (I.e, symp increases heart rate and para decreaes heart rate).
Parasympathetic actions on organs
Can act on each organ separately
Sympathetic actions
Discharges as a complete system
Sympathectomy
Cuts off sympathetic chain. Not ideal but can be done
PS v S effects on coronary vessels
PS constricts, S dilates
PS vs S actions on pupil
PS constricts, S dilates
Preganglionic parasympathetic NT and receptor
ACh and nicotinic receptor
Preganglionic sympathetic NT and receptor
ACh and nicotinic
Postganglionic parasympathetic NT and receptor
ACh and muscarinic
Most post ganglionic sympathetic NT and receptors
Norepi and adrenergic
Some postganglionic sympathetic NT and receptors
ACh and muscarinic. Only in sweat glands and arrector pili muscles
What is the main contributor of the ANS
Hypothalamus
Other contributions to ANS
Lambic system, brain, and spinal cord
Another name of sympathetic nervous system
Thoracolumbar
Where are the first cell bodies in the sympathetic nervous system found
In the Intermediolater nucleus (IML) of T1-L2
Intermediolateral nucleus
A group of cell bodies in the lateral horn of the spinal cord
Paravertebral ganglia
Are part of the sympathetic chain seen on either side of the vertebral columns
Prevertebral ganglia
Sit in front of the vertebral bodies
Rami communicates
Are the connecting branches between the spinal nerve adn teh sympathetic chain. There are both white and grey
White rami
Lateral and Preganglionic so it is myelinated
Great rami
Medial and postganglionic therefor unmyelinated
Preganglionic axons start in the IML, travel through the white rami into the sympathetic chain and then have 3 choices
1)Synapse immediately
2) Ascend or descend to another vertebral level ganglia to synapse
3) Exit without synapsing at all (Splanchnic) (still preganglionic, myelinated)
Splanchnics
Thoracic splanchnics are greater, lesser, and least. (T5-T9), (T10-T11), and (T12) respectively.
Where do teh preganglionic fibers of the splanchnics leave and synapse
Leave the sympathetic chain and synapse in the abdominal prevertebral ganglia
What do all splanchnic nerves innervate
Viscera
Where are the first cell bodies of the parasympathetic NS located
Brain stem
What are the parasympathetic head and neck ganglia
Cilliary, pterygopalatine, submandibular, otic
What cranial nerve is the ciliary head and neck ganglia associated with
CN III
What cranial nerve is the pterygopalatine head and neck ganglia associated with
CN VII
What cranial nerve is the submandibular head and neck ganglia associated with
CN VII
What cranial nerve is the otic head and neck ganglia associated with
CN IX
Where are the parasympathetic head and neck ganglia located
In the walls of viscera
Two neuron system
Preganglionic fiber that’s myelinated and a postganglionic fiber that’s unmyelinated
Where are the first and second cell bodies in the sacral portion located
First cell bodies are located in S2-S4. Second cell body is in the organ wall.
What are the parasympathetic brain stem nuclei and associated CN
Edinger-westphal (III), superior salivatory (VII), inferior salivatory (IX), Dorsal n of vagus (X)
Cardiopulmonary splanchnics
Post ganglionic sympathetic
Thoracic splanchnics
Preganglionic sympathetic
Pelvic splanchnics
Preganglionic parasympathetic
Sacral splanchnics
Postganglionic sympathetic
Lumbar splanchnics
Preganglionic sympathetic
What are the three plexi in the thorax
Cardiac plexus, pulmonary plexus, esophageal plexus
What plexi are the same but differ in location
Cardiac and pulmonary
Where is the cardiac plexus
The superior mediastinum
What are the two regions of the cardiac plexus
Superficial cardiac plexus in the concavity of the aortic arch. deep cardiac plexus between the aortic arch and trachea.
Where are the first cell bodies of the sympathetic NS
The IML of T1-T6
Cell body number two of the sympathetic NS is called a _____________
Cardiac nerve
How are the second cell bodies in the sympathetic NS named
Respectively based off the ganglia it came from
Second cell bodies of the sympathetic NS
Superior sympathetic cardiac nerve, middle sympathetic cardiac nerve, inferior cardiac nerve, T1-T4 cardiac nerves
What are the origins of the cardiac nerves
Superior ganglia, middle ganglia, inferior ganglia, T1-T4 thoracic sympathetic ganglia
What is the parasympathetic supply to the heart and cardiac plexus
Cardiac branches (CNX) and they are preganglionic
Parasympathetic contribution to the pulmonary plexus
Preganglionic from vagal nuclei to ganglia. Postganglionic from cell body number two to target
Sympathetic contribution to pulmonary plexus
Preganglionic (#1) from IML T1-T6 to cervical ganglia and T1-4 chain ganglia (#2). Cardiac nerve and postganglionic to targets.
Parasympathetic effects on the lungs
Vasodilate, bronchoconstriction, increased mucus secretion
Sympathetic effects on lungs
Vasoconstriction, bronchodilation, decreased mucus secretion
What is the relationship of the pulmonary plexus with the deep cardiac
It is continuous with it at the tracheal bifurcation (around T4)
What does the pulmonary plexus communicate with
The esophageal plexus
What are the divisions of the pulmonary plexus
Anterior pulmonary plexus and posterior pulmonary plexus
PS effects on BP, HR, and coronary vessels
Decrease, decrease, constrict
Sympathetic effects on BP, HR, and coronary vessels
Increase, increase, dilate
What nervous system innervate the SA and AV nodes
Sympathetic
What do the SA and AV nodes do
They are the conduction system of the heart
What does the SA node do
Initiates impulse and spreads this signal to both atria via the AV node and Bachmann’s bundle
What does the AV node do
Electrically connects the atria and ventricles
Bundle of Hiss
Extension of the AV node into the interventricular septum is called the bundle of Hiss
