Thorax Flashcards
What are the boundaries of the thoracic cavity
Cranial: thoracic inlet
Caudal: diaphragm
Lateral: ribs, muscles, skin
Dorsal: vertebrae, muscles, skin
Ventral: sternum, muscles, skin
Origin and insertion of serratus dorsalis cranialis
O: thoracic fascia and spines of first 6-8 thoracic vertebrae
I: cranial border and lateral surface of ribs 2-10
Action of serratus dorsalis cranialis
Lift ribs for inspiration
Origin and insertion of serratus dorsalis caudalis
O: thoracolumbar fascia
I: caudal border of last 3-8 ribs
Action of serratus dorsalis caudalis
Draw last few ribs caudally for expiration
External intercostal muscles run…
Craniodorsally to caudoventrally
Internal intercostal muscles run….
Caudodorsally to cranioventrally
External intercostal pulls ribs ____________ to assist in ________________
Cranially; inspiration
Internal intercostal pulls ribs ____________ to assist in ___________
Caudally; expiration
Where is transversus thoracis (parasternal) located
Inside ribcage from sternum to costochondral junction
Transversus thoracis pulls the costal cartilages __________ to assist with _______________
Inward; expiration
What muscles assist inspiration
Serratus dorsalis cranialis; external intercostal
What muscles assist expiration
Serratus dorsalis caudalis; internal intercostal; transversus thoracis (parasternal)
What are the epaxial muscles
Iliocostalis thoracis, longissimus, Spinalis thoracis
Where is rectus thoracis
From the 1st to 4th rib
What muscle acts to retract the ribs and keep the ribcage in place
retractor costae
What muscle acts to elevate the ribs and where is it located
levator costae; between the transverse processes of the vertebrae and upper aspect of the rib
What are four thoracic wall nerves
dorsal cutaneous, lateral cutaneous, lateral thoracic (innervates pectoralis), intercostobracial
where are VANs located
on the caudal border of the ribs
What is pleura
serous membrane that folds onto itself to form a two layered bag (visceral and parietal pleura)
T/F visceral pleura is only surrounding the lungs
T; costal, diaphragmatic, cupular and mediastinal pleura is parietal
what is the term for where the pleura extend beyond the first rib
the pleural cupulae
What are the four types of parietal pleura
costal, diaphragmatic, mediastinal and cupular
What is chylothorax
lymph in the thorax
what is the line of pleural reflection
where the costal pleura connects with the diaphragmatic pleura
what is the location of the cardiac notch in horses and what is its importance
3rd-6th intercostal spaces; if you put a needle in here it will not pierce the pleura
where is the location of the cardiac notch in cows
3rd-4th intercostal space
what separates the thoracic and abdominal cavities
the diaphragm; has tendinous and muscular regions
what are the parts of the diaphragm
tendinous: central tendon and L/R crura
muscular: sternal and L/R costal portions
what are the three main openings in the diaphram
aortic hiatus, esophageal hiatus, caval foramen (for caudal vena cava)
what is the purpose of the crura
attach to the ventral aspect of the 3rd/4th lumbar vertebrae centra
what animals are prone to chylothorax
cats
T/F the thoracic duct is paired
False; only on the left side
what is the path of the thoracic duct
extends from the cysterna chylii (in the abdomen) through the aortic hiatus (in the diaphram) into the jugular vein or cranial vena cava (in the thoracic cavity)
at what point does vagus split into dorsal and ventral branches
after crossing the heart
what is the path of the left recurrent laryngeal nerve
passes under the aorta, then loops up to innervate the pharyngeal muscles (exception = cricothyroid)
what is the path of the right recurrent laryngeal nerve
curves around the right subclavian artery
at what point does the vagus and sympathetic trunk separate
at the thoracic inlet; in the neck it is the vagosympathetic trunk
what is the importance of the cervicothoracic ganglion
where sympathetic innervation to the head passes through (and joins in the vertebral nerve)
T/F the cervicothoracic ganglion is parasympathetic
False; it is sympathetic
Where is the cervicothoracic ganglion located
head of the 1st rib
Left azygous vein is only in __________
ruminants; all other species have only right azygous vein
the bifurcation of the trachea occurs ________ to the heart and is called the _________
dorsal; carina
tracheal cartilage is open _________
dorsally
what closes the gap in tracheal cartilage
trachealis m.
describe the left and right lobes of the small animal lung
left: cranial cranial lobe, caudal cranial lobe, caudal lobe
right: cranial lobe, middle lobe, caudal lobe, accessory lobe
describe the left and right lobes of the horse lung
left: no cranial or caudal lobes (all one big lobe)
right: cranial lobe, caudal lobe, accessory lobe (no middle lobe)
describe the left and right lobes of the bovine lung
left: cranial cranial lobe, caudal cranial lobe, caudal lobe
right: cranial cranial lobe, caudal cranial lobe, middle lobe, caudal lobe, accessory lobe
what is the extent of the ruminant heart
2-5 IC
what is the extent of the horse heart
2-6 IC
what is the extent of the dog heart
3 rib to 6 IC
what is the extent of the cat heart
3 IC to 6/7 rib
what lies between the sternum and the heart? what is its job
sternopericardial ligament; maintains apex of pericardial sac in fixed position near the sternum
what lies between the diaphragm and the heart
phrenicopericardial ligament; maintains apex of pericardial sac in fixed position near the diaphragm
what is the importance of the auricle
reduces turbulence in the atria
what is an important structure that is only found in the right ventricle? what is its job
septomarginal trabeculae (aka moderator band); limits movement of the right side of the heart and conducts pulses
the _____ ventricle is more cranial than the ____ ventricle
right is more cranial than the left
in neonates, there is a _______________ between the pulmonary artery and the aorta; in adults, the ___________________ becomes the _________________
in neonates, there is a DUCTUS ARTERIOSUM between the pulmonary artery and the aorta; in adults, the DUCTUS ARTERIOSUM becomes the LIGAMENTUM ARTERIOSUM
what is the purpose of the ductus arteriosum
shunts blood from the pulmonary circulation into the aorta, since the lungs are non-functional
describe the orientation of the heart
right ventricle is more cranial than the left ventricle, but 60% of the heart is on the left side
the heart base is located (dorsally/ventrally) whereas the apex is located (dorsally/ventrally)
base is located dorsally, apex is located ventrally
what is the angle of the heart in cats
30 degrees
what is the angle of the heart in dogs
45 degrees
what is the angle of the heart in cows
75 degrees
what is the angle of the heart in horses
90 degrees
describe PAM in horses
PAM, 3 low, 4 high, 5 low
the left heart base includes what valve(s)
pulmonic and aortic
the left heart apex includes what valve(s)
mitral (bicuspid)
the right mid heart includes what valve(s)
tricuspid
the right heart sternal border allows you to diagnose what
VSD
where would you listen for the tricuspid valve
low in the 3rd or 4th IC on the right side
describe PAM in cows
PAM, 3 low, 4 high, 4 low
describe the connections to the heart tricuspid and bicuspid valves
from septum inward: papillary muscles, cordae tendinae, valves
describe the branches of the left coronary artery
paraconal (in the paraconal groove) and circumflex (in the atrioventricular groove)
describe the branches of the right coronary artery
becomes subsinuosal branch (in horse and pig)
coronary arteries are filled in ________
diastole (when blood backflows into the aorta but the aortic/pulmonic valves have closed)
there is/are ______ aortic sinuses and ________ coronary sinuses
3 aortic, 1 coronary
the coronary sinus is the termination of what vein
the great cardiac vein
what is one potential consequence of surgery in the abdomen or thorax on the heart
disturbing parasympathetic fibres (i.e. vagus) will slow the heart rate
what is the hole in the fetus that connects the left and right sides of the heart
fossa ovalis
