Thorax Study Guide

Aortic valve Auscultation: over the right ICS2

Pulmonary valve Auscultation: over the left ICS2

Bicusid valve: apex of the heart: 6-7 cm from the median plane generally in ICS 5

Tricuspid valve Auscultation: left ½ of the lower end of the body of the sternum at ICS4

Secondary pulmonic: Left ICS3

Tricuspid valve
On the right between the RA and RV
Behind the right ½ of the sternum opposite ICS4

Bicuspid/mitral valve
On the left between the LA and LV
Behind the left ½ of sternum opposite costal cartilage 4

Aortic valve: between LV and aorta
Left ½ of sternum opposite ICS3

Pulmonary valve: between RV and pulmonary artery
Behind the medial end of the 3rd left costal cartilage

The left lung has one fissue (oblique) and two lobes (superior and inferior)

1. Cardiac notch at costal cartilage 4,5,6
2. Lingula
3. Groove for aortic arch and descending aorta

Superior lobe

The right lung has 2 fissures (oblique and horzontal) and 3 lobes (superior, middle, and inferior)

1. Tracheal and esophageal area
2. Groove for SVC and IVC
3. Groove for azygous vein

The pulmonary artery is superior to the bronchi in the left lung

The pulmonary artery is anterior to the bronchi in the right lung

Oblique fissure begins 2.5 cm (1 inch) from apex of lungs and ends at costal cartilage 6

Horizontal fissure is located at costal cartilage 4

Aortic valve Auscultation: over the right ICS2

Thoracic duct begins at L2 as the cisterna chyli

Entire left side of the body and right abdomen and leg→ cisterna chyli→ thoracic duct
at T5/6, the thoracic duct crosses over to the left behind the esophagus—> enters the left internal jugular vein and subclavian vein behind the subclavian artery —> SVC

Only the right head, neck, thorax, and arm drains into the right lymphatic duct —> R internal jugular vein —> SVC

Blood supply to heart is by branches of right and left coronary arteries from the ascending aorta

1. SA nodal artery (supplies SA node)
2. AV nodal artery (supplies AV node)
3. Posterior interventricular (posterior desending a. supplies right + left ventricle +posterior 1/3 of septum)

SA nodal a. - supplies the SA node

AV nodal a. - supply the AV node

Posterior interventricular —> posterior descending a. supplies part of right and left ventricle and posterior 1/3 of interventricular septum

1. Left anterior desending LAD
2. Circumflex artery

1. Anterior left ventricular wall
2. Anterior 2/3 of interventricular septum
3. Bundle of His
4. Apex

1. Left border of heart via marginal artery
2. Posterior-inferior left ventricular wall

wall of the RA, superior to the crista terminalae at the junction of the anteromedial aspect of the SVC and right auricle || notes:Mnemonic: The SA node is always right. It thinks that it is superior to Cristae. It puts itself before and center to superior people and right people.

Branch of the right coronary artery

interatrial septum on the ventricular side of the orifice of the coronary sinus || notes:Mnmenonic: AV node has an infection interatrial septum on the ventricular side of its sinus

branch of the right coronary artery

Bronchial arteries supply the conductive airway (non respiratory)

One on the right from the third posterior intercostal artery

2 on the left come from the thoracic aorta

Pulmonary arteries to the terminal portion of the bronchioles

Azygus v.

Hemi-azygus v.

Aspirated foreign bodies will enter the right main bronchus (because it is shorter, wider, and more vertical) -> will go to lower base of right inferior lobe

Costal cartilage 7-10

T4

T10/11

Posteriorly – T1 vertebral body
Anteriorly – superior border of manubrium
Laterally – first rib and costal cartilages

• Trachea
• Esophagus
• Vagus (CN X) and Phrenic (C3-C5) nerves
• Apex of Lungs (cupula)

Clinical outlet

Thoracic outlet syndrome: caused by pancoast tumor, extra cervical rib, or compression of scalene muscles—> compression of brachial plexus

-Posteriorly – T12 vertebral body
-Posterolaterally – 12th ribs
-Anterolaterally – costal margin (costal cartilages 7-10)
-Anteriorly – Xiphoid Process

1. Caval opening (T8)
2. Esophogeal opening (T10)
3. Aortic opening (T12)

Caval Opening (T8)- only “true hole” because its going through the central tendon.

IVC
Phrenic nerves (C3-5)
Lymphatic vessels

esophagus
Right and left vagus nerves (CN 10)
Esophageal branches of the left gastric artery and vein

Thoracic aorta
Thoracic duct
Great splanchnic nerves (T5-9)
Azygous vein

External Intercostal muscles- (down and forward)
for INSPIRATION

Internal Intercostal Muscles- fibers running down and backwards
For EXPIRATION

Innermost intercostal muscles- fibers run down and backwards-
for EXPIRATION

1. Innermost proper- between ribs
2. Subcostalis- angle
3. Sternocostalis transversus thoracis- near the sternum

Inferior to every rib, there’s a costal groove that has the neurovascular nerve bundles (VAN) [superior→ inferior]

Rib 1 doesn’t have a costal groove but has groove for subclavian v and a

VAN travels between the internal and innermost intercostal muscles

Thorocentesis- make sure to go at most inferior part of intercostal space, or superior to the inferior rib )When adminsitering nerve block, you WANT to hit the nerve.

Skin
Superficial fascia
Deep fascia
Serratus anterior muscle
External intercostal m.
Internal intercostal m
Innermost intercostal m
Innermost
Subcostalis
Sternocostalis transversus thoracic
Endothoracic fascia *
Parietal pleura
Pleural cavity
Visceral pleura
Lungs

In a thoracentensis, you would want to enter mid-axillary (up to ICS 9)

Endothoracic fascia- CT layer that prevents the parietal pleura from rubbing against the innermost intercostal m. It is thickened over the apex of the lung at the cupula = Sibsons fascia.

Trachea deviates to affected side (when there is empty space):
Atelectasis
Pneumonectomy - removing a lung
Large pleural fibrosis
Pulmonary agenesis -absense of lung

Trachea deviates to the opposite side (when space is being filled and pressure increases):
Tension pneumothorax
Pleural effusions- water buildup around lung
Hemothorax
Large mass

Pneumothorax- air in the pleural space causing the lung to collapse around the hilus
- may push mediastinal contents (ex: heart and great vessels) towards the other lung
(ex: can result after stab wound)- air escapes when breathing [loss of negative pressure] and can cause lung collapse

Phrenic- lateral and anterior to hilum

Vagus- posterior to hilum

Phrenic: runs anterior to root/ hilum of the lungs. Located between parietal pleura and pericardium

Right (lateral) of SVC and RA

Travels over the arch of the aorta then POSTERIOR to the hilum to reach the esophagus

Posterior to root of right lung
Posterolateral to brachiocephalic trunk
Medial to right phrenic
Lateral to trachea

Between the LCC and left subclavian
Crosses the left side of the aortic arch
Posterior to the root of the lung
Crossed by the left phrenic below the aortic arch || notes:-Stuck in the middle (LCC and left subclav)
-Cross the arch (aortic arch)
-Gets behind the root (of the left lung)
-Crossed by phrenic below (aorta)

Mass extending anteriorly will occlude the phrenic nerve, mass extending posteriorly will occlude the vagus nerve

1. Entering below the xyphoid process
2. Entering in the ICS at the left infrasternal angle

Skin -> subcutaneous tissue- > rectus abdominus m. -> rectus sheet -> rectus muscle (now in pericardium-see pericarial layers)

-Internal thoracic vessels
-Skin -> subcutaneous tissue -> external intercostal membrane -> costochonral joint -> intercostal muscles (now in pericardium - see pericardial layers)

Fibrous pericardium -> SEROUS- parietal layer -> pericardial cavity -> visceral layer (AKA epicardium) - - -> HEART (epicardium -> myocardium -> endocardium -> chambers of heart)

Left recurrent laryngeal nerve hooks under the arch of the aorta, distal/lateral to the ligamentum arteriosum (at the angle of Louis where it may be damaged by pathology (aneurism of aorta, malignancy…) resulting in paralysis of the left larynx and vocal cord

The right recurrent laryngeal nerve will not be affected because it arises from the right vagus nerve in the root of the neck and it hooks under the right subclavian artery.

Either the right or left recurrent laryngeal nerves may be damaged during thyroid gland surgery

The mediastinum contains all of the structures of the thorax EXCEPT for the lungs, pleural membrane, and pleural cavity

Sternum→ Ascending aorta→ SVC→ arch of aorta→ pulmonary artery and bronchi (underneath the arch of the aorta , between ascending and descending aorta) → descending aorta→ trachea → esophagus → vertebrae

ICS 1-6 – anterior intercostal arteries from internal
thoracic artery
ICS 7-9 – anterior intercostal arteries from
musculophrenic artery (branch of internal thoracic)
ICS 10-11 – no anterior intercostal arteries

ant thor wall = internal thoracic a.

ICS 1 – highest intercostal artery (AKA 1st posterior intercostal artery)
from costocervical trunk
ICS 2-11 – posterior intercostal arteries from thoracic aorta
ICS 12 – subcostal artery from thoracic aorta

post thor wall = thoracic aorta EXCEPT ICS 1
-> costocervical trunk

Lungs Arteries: bronchial arteries (two on left, one on right), pulmonary arteries

Trachea: superior thyroid a, inferior thyroid a, bronchial a, internal thoracic a

Bronchi: bronchial arteries, pulmonary arteries

Esophogous: inferior thyroid a, bronchial a, esophogeal a, phrenic a, left gastric-> esophageal

Pericardium: pericardiophrenic, musculophrenic

Heart: right coronary and left coronary a

The anterior supply of thorax is drained the by the Internal Thoracic Vein (into the Brachiocephalic vein)

The posterior supply of the thorax is drained by the azygos system

Azygos veins drain deoxygenated blood from posterior walls of the thorax and abdomen into the SVC

ICS 1 - highest intercostal vein → brachiocephalic vein
ICS 2-3 - highER intercostal vein → azygos
ICS 4-11 - azygos
ICS 12 - (subcostal vein) → azygos

ICS 1 - highest → brachiocephalic vein
ICS 2-4 - accessory hemiazygos → azygos vein
ICS 5-12 - hemiazygos vein → azygos vein

Fossa ovalis
Pectinate muscle (and smooth edge- crista terminalis)
Opening of tricuspid valve
Opening of coronary sinus- Thebesian valve
Opening of SVC/IVC
Opening of anterior cardiac veins || notes:For Pecs, try corn serve veins

Tricuspid valve
Pulmonary trunk
Papillary muscle
Moderator band/septomarginal trabecula from the anterior papillary muscle
Chordae tendinae || notes:Try Pulling Paps Moderate Cancer

Opening of pulmonary veins
Opening of bicuspid valve
Auricles (Right and left and Have pectinate muscles)

Bicuspid valve
Opening of ascending aorta
Chordae tendinae
Papillary muscles || notes:Buy AA cancer Paps

In the ventricles the trabeculae carnae is all the structures except the cusps, chordae tendinae, and septomarginal trabecula

The pectinate muscle in found in the RA, and right and left auricle only

1. Prevent back flow of blood into atrium
2. Prevent eversion of valves during ventricular contraction
3. Attach papillary muscles to cusps of AV

Superior: thoracic inlet and root of the neck
Inferior: diaphragm
Anterior: sternum
Posterior: vertebral column

Entire mediastinum is T1-T12 (superior T1-4, inferior T5-12)

The superior mediastinum is located posterior to the manubrium and anterior to the first 4 thoracic vertebrae

Phrenic Nerves
Vagus Nerves
Thoracic Duct
Left Recurrent Laryngeal (not right)
Brachiocephalic Vein (via SVC)
Aortic Arch (and branches)
Thymus
Trachea
Lymph Node
Esophagus

Brachiocephalic veins= subclavian+ internal jugular

SVC= R+L brachiocephalic veins

Below T4

1. Anterior (posterior sternum to ant percardial sac)
2. Middle
3. Posterior (posterior pericardial sac and diaphram + T12)

1. Fat
2. Thymus
3. Lymph nodes

1. Heart
2. Pericardiym
3. Main bronchi
4. Great vessels
5. Phrenic nerve

1. Esophogous
2. Thoracic aorta
3. Thoracic ducts
4. Azygous vein
5. Vagus nerve
6. Splanchnic

1. Pulmonary veins from the lungs to the LA
2. Usually an upper and lower vein
3. SVC enters the RA
4. IVC enters the RA
5. Anterior cardiac veins enter the RA
6. Coronary sinus enters the RA

1. Ascending aorta leaves LV
2. Pulmonary trunk and pulmonary arteries leave RV (Crosses arota and divides into right and left pulm arteries at angle of louis. Left travels over left bronchus. Right is posterior to asending aorta and SVC. Pulm trunk is connected by ligamentum arteriousis.)

All of the veins of the heart drain into the coronary sinus which drain into the right atrium ***Two exceptions

Anterior cardiac veins- drains directly into RA
Venae chordae minimae- mostly drains directly into RA

Right lung- pulmonary artery is anterior to primary bronchus

Left lung- pulmonary artery is superior to primary bronchus

Right Bronchus
Wider, shorter, and more vertical
Before entering hilum of lung it gives off the superior lobar bronchus
On entering the hilum, it divides into a middle and inferior lobar bronchus

Left Bronchus
Narrower, longer, and more horizontal
It passes to the left below the arch of the aorta and in front of the esophogous (see pic below)
On entering the hilum of the left lung, it divides into a superior and inferior lobar bronchus

Primary bronchus- right and left
Secondary bronchi- lobar
Tertiary bronchi- segmental

Phrenic nerve (C3,4,5)

A pleural recess is a pleural cavities that separate the visceral and parietal pleura.

Pleural recesses allow for the expansion of lung during inspiration

Parietal pleura:
- Internal thoracic artery and
intercostal arteries
- VERY SENSITIVE TO PAIN

Visceral pleura:
- Bronchial arteries
- INSENSITIVE TO PAIN

The parietal pleura becomes continuous w/ visceral pleura at the HILUM of the lungs and forms a “cuff” that surrounds the structures entering/ leaving the lung at the root

Costodiaphragmatic recess: at the junction of the costal and diagphragmatic parietal pleura, at the mid axillary line.

The costodiaphragmatic recess is lowest area of the pleural cavity into which the lungs expand during inspiration

Anteriorly ICS 8, midaxillar ICS 9, and posteriorly ICS 10

Fluid in lungs

Costomediastinal recess:: lie along the anterior margin of the pleura

1. Brachiocephalic trunk (branches into right subcalvian and common carotid)
2. Left subclavian artery
3. Left common carotid

Atypical ribs- 1,2,10, 11,12

Rib 7 is longest, rib 12 is shortest

Rib dislocation- displacement of costal cartilage from sternum at ribs 2-7 (contact sports)

Rib separation- dislocation of the Costochondral joint between the rib and its costal cartilage

The trachea Begins as the contiinuation of the larynx at the lower border of the cricoid cartilage (C6)

The trachea descends into the midline of the neck anterior to the esophogous entering the superior mediastinum and deviating slightly to the right of the median plane at the angle of Louis before it divides

The trachea ends in the thorax by dividing into the right and left primary bronchi at the sternal angle (T4-5) at the Carina

Angle of the carina is about 90 degrees. If its greater than that -> may indicate the presence of a mediastinal mass

Posterior surface of trachea is flat and is covered by trachialis muscle

1. Sternum
2. Thymus
3. Arch of aorta
4. Brachiochephalic trunk origin
5. Left common corotid

Esophogous

1. Superior thyroid artery
2. Inferior thyroid artery
3. Bronchial artery
4. Internal thoracic artery

Vagus and sympathetic chain

Esophogous: it is a median structure (median plane) that lies posterior to trachea and left atrium

The esophogus is the the main posterior relationship of the base of the heart

The esophogus deviates to the left, posterior to the left main bronchus and it enters the diaphragm at T10 anterior to the aorta with the vagus and the esophageal branch of the left gastric artery and vein

1. Vagus nerve
2. Sympathetic fibers
3. Pain fibers

Pericardium- fibrous sac that encloses heart and vessels
Located in middle mediastinum, posterior to the body of the sternum and 2-6 costal cartilages, and anterior to T5-8 vertebrae

Transverse Sinus: located behind the aorta and pulmonary trunk, and in front of the left atrium and SVC
Important during bypass- you can stick your finger between great arteries and pulmonary trunk

Oblique Sinus: between the pulmonary veins and IVC

Nerve supply to Pericardium:

Fibrous pericardium is supplied by
-Phrenic n (C3-5)- located between the parietal pleura and fibrous pericardium)
-Vagus n

- The visceral layer is supplied by the coronary plexus

To decompress a cardiac temponade, do a pericariocentesis- place the needle at the left infrasternal angle through the cardiac notch of the L lung

Heart:
-Base is posterior and apex is inferolateral
-It is related to sternum, the costal cartilages and the medial ends of the ribs 3-5 on the left
-Posteriorly, it extends from T6-9

Right border: RA
Left border: LV
Apex: tip of left ventricle, found in ICS5 about midclavicular line
Superior border: right and left auricles and the conus arteriosus (area from which pulmonary trunk arises) of the RV
Inferior border: diaphragm by the RV

IVC/SVC -> RA -> tricuspid valve -> RV -> pulmonary valve ->pulmonary artery -> lungs -> pulmonary vein -> LA -> mitral valve -> left ventricle -> aortic valve -> aorta -> body

Innervation of the heart: cardiac plexus formed by branches of vagus and sympathetic trunks