Lecture 10: Small Animal thorax and Diaphragm Flashcards
The trachea is a tube that extends from the ___cartilage of the larynx to its ___in the thorax
Cricoid cartilage, biforcation
What is the tracheal carina
Structure that lies at the crest of the bifurcation where the trachea splits
How many C shaped hyaline cartilages line the trachea
35-40
What muscle lines the often part of the C-shaped hyaline tracheal cartilages
Trachealis muscle
Is the trachealis muscle dorsal or ventral
Dorsal
What structure unites the hyaline tracheal cartilage rings
Annular ligaments of the trachea
When does the bronchial tree begin
Bifurcation of the trachea
The right and left principal bronchi divide into __
Lobar bronchi
What structure is used to identify the lung lobes
Lobar bronchi
Lobar bronchi divide into
Segmental bronchi
Which lung/bronchus segment lacks hyaline cartilage
Bronchioles
Respiratory bronchioles give rise to ___. ___ and ___
Alveolar ducts, alveolar sacs and pulmonary alveoli
what is wrong
Tracheal collapse
What breeds commonly get tracheal collapse
Middle aged toy breeds, Yorkies and poms
What happens during tracheal collapse
C-shaped tracheal cartilage weakens and collapses progressively over time
What are the two types/regions of tracheal collapse
Intra or extra thoracic
What form of tracheal collapse is occurring when signs worsen during inspiration
Extrathoracic
What form of tracheal collapse is occurring when signs worse during expiration
Intrathoracic
What is grade I tracheal collapse
Tracheal membrane is slightly pendulous, cartilage maintains normal shape and lumen size is reduced by 25%
What is grade II tracheal collapse
Tracheal membrane is widened and pendulous, cartilage is partially flattened, and lumen size is reduced by 50%
Grade III tracheal collapse
Tracheal membrane almost in contact with the ventral trachea, cartilage is nearly flat and lumen size is reduced by 75%
Grade IV tracheal collapse
Tracheal membrane lying on dorsal cartilage, cartilage is flattened and may invert, and lumen is essentially closed
What grades is medical management reasonable for tracheal collapse
Grade I and II
What are some medical management options for grade I and II tracheal collapse
- Weight loss plan
- Harness instead of collars
- Avoid respiratory irritants
- Steroids, antiussives, bronchodilators, and sedatives
What are two surgical options to treat tracheal collapse
Extraluminal rings and intraluminal stents
What is the thoracic inlet
Opening into the cranial part of the thoracic cavity
What could happen to patient under anesthesia if your ET tube is passed the thoracic inlet
You would only be inflating one lung/side because your tube is passed he bifurcation
What is the mediastinum
Central compartment of the thoracic cavity
What does the cranial mediastinum contain
Trachea, esophagus, thymus
What does the middle mediastinum contain
Heart
What does the dorsal mediastinum contain
Major pulmonary vessels, aorta, thoracic duct
What does the caudal mediastinum contain
Aorta, thoracic duct, esophagus, vagus nerve, etc.
Identify 1-14
1.right cranial lung lobe
2. Right middle lung lobe
3. Right caudal lung lobe
4. Accessory lung lobe
5. Cranial part of left cranial lung lobe
6. Caudal part of left cranial lung lobe
7. Left caudal lung lobe
8. Caudal mediastinum
9. Trachea
10. Right ventricle
11. Left ventricle
12 aorta
13. Caudal vena cava
14. Heart
What is #2
Bronchus to right cranial lung lobe
Left lateral thoracic the __side is down and ___ side is up
Left down, right up
In a left lateral thoracic rad which side of the lungs has more air
Right
During a left lateral thoracic radiograph there is more air in the right side, therefore which side is easier to see
Left side, less air so can see more soft tissue opacity
__produces large impression on the medial surface of each lung
Heart
What side is the cardiac notch on
Right
If you are doing a pericardiocentesis which side should you do it from and why
The right, because you are aiming for the cardiac notch
What side is the accessory lobe of the lung on
Right
What is the alveolar disease pattern
When air within alveoli is replaced with a denser material (ex: pus), increasing opacity
What is a bronchial disease pattern
When bronchial wall thickness is increased by cellular or fluid infiltration
What are the two types of interstitial disease patterns
Structured and unstructured
What is structured interstitial disease patterns
Nodular or mass lesions in the lung
What is unstructured interstitial disease pattern
Excess fluid, cellular in growth, or inflation into the supporting interstitial framework of the lung
What are air bronchograms
Air filled bronchus transversing a region of abnormal lung where alveolar air has been replaced by hemorrhage
What is the lobar sign in pulmonary disease
Sharp margin crated when a lobe with increased opacity abuts a normally aerated lobe that has less opacity
What are the 2 hallmarks of bronchial pattern
Ring shadows and tram lines
*tram lines more present
What are ring shadows
Crated by the x-ray beam hitting an abnormal bronchus head on
What are tram lines
Created by the x-ray beam hitting abnormal bronchus side on
What is the key to understanding unstructured interstitial patterns
Recognizing an increase in the background opacity of the lung of that which is within normal limits
What valves can you listen to on left side and where
P: pulmonary (3rd rib)
A: aortic (4th rib)
M: mitral (5th rib)
What valve can you listen to on right side
Tricuspid- 4th interstitial space
What structure separates the L and right ventricle
Left coronary artery
What structure separates the atriums from the ventricles
Great coronary vein
what is indicated by 1-2
- Left coronary artery
- Great coronary vein
What is the order of cardiac blood flow
- Caudal vena cava
- Right atrium
- Tricuspid valve
- Right ventricle
- Pulmonary valve
- Pulmonary artery
- Pulmonary veins
- Left atrium
- Mitral valve
- Left ventricle
- Aortic valve
- Aorta
What structure starts the sequence of cardiac blood flow by causing atrial contraction
Sinoatrial node
Describe the pathway from SA node to activating the ventricles
- SA node
- AV node
- Bundle of His
- Bundle branches
- Purkinje fibers
- Ventricular contraction
What is the pericardium
Heart sac,
What are the two parts of the pericardium
Fibrous and serous
What is the fibrous layer of the pericardium
Tough outer sac that contains serous pericardium, a small amount of fluid and the heart
What are the two layers of the serous pericardium
Parietal and visceral
What is the parietal pericardium
Covers the inner surface of the fibrous pericardium
What is the visceral pericardium
Epicardium, attached firmly to the heart muscle, except where fat or vessels intervene
What muscles prevent inversion or prolapse of the atrioventricular valves
Papillary muscles
What do the papillary muscles attach to valves via
Chordae tendiane
What valve separates the left atrium and left ventricle
Mitral
What valve separates the right atrium and right ventricle
Tricuspid
T or F: semilunar valves have papillary muscles
False
What is systole
When heart contracts and pumps blood from chambers into the arteries
What is diastole
When heart relaxes and allows the chambers to fill with blood
What is a grade I heart murmur
Very soft murmur only audible on listening carefully for some time
What is a grade II heart murmur
Soft murmur that is audible with careful auscultation
What is a grade III heart murmur
Moderate murmur immediately audible with auscultation
What is a grade IV heart murmur
Loud murmur without a thrill
What is a grade V heart murmur
Loud murmur with a palpable thrill
What is a grade VI heart murmur
Audible with stethoscope held slightly off chest wall
Each lung has a supply of what 3 structures
Artery, bronchus and vein
label 1-3
Artery, bronchus, and vein
The artery, bronchus, and vein that supply each lung should be smaller than __
A rib
What breeds is patent ductus ateriosus common in
Maltese, poodles, poms, Bichon Frise, chihuahuas, GSD’s
What is the classic machinery murmur
Patent ductus arteriosus
What causes patent ductus arteriosus
Failure to close ductus ateriosus after birth. Important in utero so blood bypasses lungs that aren’t formed but should close after birth
PDA if left untreated has a high mortality rate and causes ___ sided congestive heart failure
Left
What are some treatment options for PDA
Surgical ligation or ductal occuluder
What is heart failure
Clinical syndrome resulting form heart disease that causes inadequate circulation of blood to peripheral tissues
What are the three categories of heart failure
- Myocardial failure/systolic dysfunction
- Valvular regurgitation or obstruction leading to volume overload
- Increased myocardial stiffness/diastolic dysfunction
What does right sided heart failure cause
Backup of blood coming from abdomen—> caudal vena cava
what is indicated by the arrow and what side of heart failure caused this
Ascites- fluid in abdomen caused by right sided heart failure
What causes left sided heart failure
Issue with the lungs, fluid is going to the left side and joining with the lungs, getting backed up and causes pulmonary edema
What is the problem here and what side heart failure is causing this
Pulmonary edema caused by left sided heart failure
Which is indicated of left and right sided heart failure
Top: right sided heart failure (fluid in abdomen)
Bottom: left sided heart failure (pulmonary edema)
What is congestive heart failure
Diminished cardiac function from edema, increased venous pressure
what is wrong here
Congestive heart failure
What is wrong here
Pulmonary congestion- pulmonary vessels increase in size
What is wrong here
pericardial effusion
What is the most common cause of pericardial effusion
Neoplasia
Pericardial effusion can cause cardiac ___
Tamponade
What is cardiac tamponade
Decreased venous return, ventricular filling, and cardiac output
What intercostal space is pericardiocentesis performed
4-6th
What lobes of the lung is the cardiac notch between
Right cranial and right middle
What structure is a lymphatic glandular organ responsible for T cell production
Thymus
Where is the thymus located
Chest cavity, cranial to the heart
What is thoracocentesis
Removal of fluid or air from the pleural space for diagnostic or therapeutic purposes
When would you place a thoracostomy tube
Pleural effusion, pneumothorax or post-operative
Why do you want to tunnel a thoracostomy tube
Barrier in the way from keeping air or something else from leaving
What are the 3 parts of the diaphragm
- Lumbar
- Costal
- Sternal
What part of the diaphragm forms the left and right crura. Also serve as tendinous attachments to bodies of L3 and L4
Lumbar
What part of the diaphragm is from the medial surface of 8th-13th ribs. Interdigitates with transversus abdomimus muscle
Costal
The costal region of the diaphragm interdigitates with what muscle
Transversus abdominus
What part of the diaphragm run from the dorsal surface of the sternum. Have a cupola- dome shaped that bulges into the thorax, and a V shaped tendinosus center
Sternal
The stomach is always next to what crus
Left crus
When in left lateral what crus is cranial
Left crus
When in right lateral what crus is cranial
Right
What lateral are we in
Left
What lateral are we in
right
patient is in left lateral, label 1-6
- Right crus
- Left crus
- Stomach
- Caudal vena cava
- Heart
- Cupola
patient is in right lateral, label 1-6
- Right crus
- Left crus
- Stomach
- Caudal vena cava
- Cupula
- Heart
label 1-5
- Caudal vena cava
- Cupula
- Right crus
- Left crus
- Cupula
what is wrong here
Diaphragmatic hernia
What is wrong here
Peritoneaopericardial diaphragmatic hernia
What is peritoneopericardial diaphragmatic hernia
Congenital communication between pericardial and peritoneal spaces.
Abnormal development of transverse septum of diaphragm
What nerve provides PNS control of heart, lungs and GI
Vagus
What nerve provides motor control of the diaphragm
Phrenic
