Gross anatomy of the thorax Flashcards
what heart chamber forms the base of the heart
left atrium
what chamber mainly forms the anterior (sternocostal) surface
right ventricle
which thorax vertebrae does the base of the heart lie opposite to
T5 - T8
what forms the diaphragmatic surface of the heart
mainly the left ventricle and partly by the right ventricle
what separates the two ventricles
posterior interventricular groove
describe the location of the pericardium in relation to the sternum, costal cartilagesand thoracic vertebrae
- It lies posterior to body of sternum & 2-6 costal cartilages.
- It lies anterior to 5-8 thoracic vertebrae
what are the main blood supply and drainage of the pericardium
pericardiacophrenic arteries and veins
what is the nerve supply of the fibrous pericardium
phrenic nerve
what is the nerve supply of the visceral layer of serous pericardium
branches of the sympathetic trunk and vagus nerves
how does fetal circulation differ from the adult one
The fetal circulation differs mainly from the adult one by the presence of 3 major vascular shunts:
- Ductus venosus: between the umbilical vein and inferior vena cava.
- Foramen ovale: between the right and left atrium.
- Ductus arteriosus: between the pulmonary artery and arch of aorta.
how does Myocardial Ischaemia
occur and what are the two leading causes
Myocardial ischaemia occurs when the blood flow demands of the heart exceed the blood supplied by the coronary arteries.
The leading causes of myocardial ischaemia are:
- atherosclerosis
- blockage of coronary arteries due to the accumulation of lipid plaques and/or thrombus
in what direction do the fibres of the external intercostal muscle go
downward and forward
in which direction do the internal intercostal muscles go
downward and backward
what is the name of the nerve T12 and why is it called this
subcostal nerve because it arises below the ribs
serratus posterior superior: origin insertion innervation action
spinous processes of C7-T3
superior borders of 2nd-4th ribs
2nd-5th intercostal nerves
elevate ribs
serratus posterior inferior origin insertion innervation action
spinous processes of C7-L2 vertebrae
inferior borders of 8th-12th ribs near their angles
anterior rami to T9-T12 thoracic spinal nerves
depress ribs
levator costarum origin insertion innervation action
transverse processes of C7-T11
subjacent ribs between tubercle and angle
posterior primary rami of C8-T11 nerves
elevate ribs
external intercostal origin insertion innervation action
inferior border of ribs
superior border of ribs below
intercostal nerve
elevate ribs during forced inspiration
internal intercostal origin insertion innervation action
inferior border of ribs superior border of ribs below intercostal nerve interosseous part: depresses ribs interchondral part: elevates ribs
innermost intercostal origin insertion innervation action
inferior border of ribs superior border of ribs below intercostal nerve interosseous part: depresses ribs interchondral part: elevates ribs
subcostal muscle origin insertion innervation action
internal surface of lower ribs near their angles superior border of 2nd or 3rd ribs below intercostal nerve interosseous part: depresses ribs interchondral part: elevates ribs
transverses thoracis origin insertion innervation action
posterior surface of lower sternum
internal surface of costal cartilages 2-6
intercostal nerve
weakly depress ribs
what is the foramen ovale
The FORAMEN OVALE is a hole between the right and left atria, allowing blood to pass from the right side to the left and not ever get pumped to the lungs.
what is the ductus arteriosus
The DUCTUS ARTERIOSUS allows blood to skip past the lungs and join up with the partially oxygenated blood that is being pumped out of the left ventricle.
which ribs are the “floating ribs”
11 and 12
between which thoracic vertebrae is the sternum placed
from T2-T9
which ribs are the typical ribs
3rd to 9th
describe the location of the superior mediastinum
from inlet of thorax to plane extending from level of sternal angle anteriorly to lower border of T4 vertebra posterioly
what are the contents of the superior mediastinum
- Thymus
- Three veins:
> Left brachiocephelic v.
> Right brachiocephelic v.
> Superior vena cava
> arch of aorta and its three branches (brachiocephalic trunk, left common carotid artery and left subclavian artery)
> phrenic nerve
> vagus nerve
> trachea
> oesophagus
> thoracic duct
> arch of azygos
> left superior intercostal vein
> left recurrent laryngeal nerve (branch of vagus)
describe the location of the anterior mediastinum
posterior to body of sternum and attached costal cartilages, anterior to heart and pericardium
what are the contents of the anterior mediastinum
- fat
- remnants of thymus gland,
- anterior mediastinal lymph nodes
describe the location of the middle mediastinum
between anterior mediastinum and posterior mediastinum
what are the contents of the middle mediastinum
- heart and pericardium
- beginning or termination of great vessels
- phrenic nerves
- pericardiacophrenic vessels
- lymph nodes
describe the location of the posterior mediastinum
posterior to heart and pericardium, anterior to vertebrae T5-T12
what are the contents of the posterior mediastinum
a) oesophagus
b) thoracic aorta
c) thoracic duct
d) azygos venous system
- Sympathetic trunks
- Thoracic splanchnic nerves
what is the function of the phrenic nerves
Both of these nerves supply motor fibres to the diaphragm and sensory fibres to the fibrous pericardium, mediastinal pleura, and diaphragmatic peritoneum.
what are the structures and locations where the oesophagus can be compressed
- the junction of the oesophagus with the pharynx in the neck;
- in the superior mediastinum where the oesophagus is crossed by the arch of aorta;
- in the posterior mediastinum where the oesophagus is compressed by the left main bronchus;
- in the posterior mediastinum at the oesophageal hiatus in the diaphragm.
describe the distribution of the sympathetic trunk
- T1 – T4 = Thoracic viscera
- T5 – T9 or T5 – T10 = Greater splanchnic n
- T9 – T10 or T10 – T11 = Lesser splanchnic n
- T12 = Least splanchnic n
what are the two layers of pericardium
- outer fibrous layer = Fibrous pericardium
- inner serous sac = serous pericardium
which costal cartilages does the heart lie posteriorly to and which thoracic vertebrae does the heart lie anteriorly to
- It lies posterior to body of sternum & 2-6 costal cartilages
- It lies anterior to 5-8 thoracic vertebrae
what is contained in the pericardial cavity and what is its function
- Pericardial cavity contains pericardial fluid
- acts as a lubricant
what is the thing that separates the two atria from the ventricles
The 2 atria are separated from ventricles by the atrioventricular groove ( coronary sulcus)
what separates the two ventricles
The 2 ventricles are separated by the ant. & post. Interventricular grooves
what forms the upper border of the sterno-costal surface of the heart
formed by 2-atria, mainly the left
what forms the right border of the sterno-costal surface of the heart
formed only by right atrium
what forms the lower border of the sterno-costal surface of the heart
formed mainly by the right ventricle but also by right atrium
what forms the left border of the sterno-costal surface of the heart
mainly by the left ventricle & left auricle
how many cusps does the aortic valve have
3
is the standard view of an x-ray PA or AP
PA
what is the normal size for a heart in a chest x-ray
Occupies up to 50% of the maximum internal thoracic diameter on a standard PA erect view
between which structures is the tricuspid valve found
right atrium and right ventricle
between which structures is the mitral valve found
left atrium and left ventricle
what forms the right border of the heart
right atrium
what forms the inferior border of the heart
left ventricle and right ventricle
what forms the left border of the heart
left ventricle (and some of the left atrium)
what forms the superior border of the heart
right and left atrium and the great vessels
what makes up the anterior (or sternocostal) division of the heart
Right ventricle
what makes up the posterior (or base) division of the heart
Left atrium
what makes up the inferior (or diaphragmatic) division of the heart
Left and right ventricles
what makes up the
right pulmonary division of the heart
Right atrium
what makes up the left pulmonary division of the heart
Left ventricle
The right lung contains a horizontal fissure. What rib does this fissure follow the course of?
4th
The parasympathetic supply to the lungs is derived from which nerve?
Vagus nerve
The mediastinum is divided into superior and inferior compartments by an imaginary line at what vertebral level?
T4
What forms the posterior border of the superior mediastinum
Vertebral bodies T1-T4
What are the nerve roots of the phrenic nerve
C3,4,5
What is the posterior border of the anterior mediastinum?
Pericardium
Which muscle forms the floor of the anterior mediastinum?
Diaphragm
In adolescents, which organ can be found within the anterior mediastinum?
thymus
The sternal angle is formed by the junction of which two bones?
Sternal body and manubrium
Which muscle forms the inferior border of the middle mediastinum?
Diaphragm
Which of the great vessels of the heart gives rise to the coronary arteries?
Ascending aorta
What is the anterior border of the posterior mediastinum?
Pericardium
Which part of the aorta is located within the posterior mediastinum?
Descending aorta
Via which diaphragmatic hiatus does the thoracic duct enter the posterior mediastinum?
Aortic hiatus
Which part of the sternum articulates with the clavicle?
Manubrium
Which structures do the sternal articular facets articulate with?
Costal cartilage of the ribs
What is the approximate vertebral level of the tip of the xiphoid process?
T10
Which option correctly describes the contents of the costal groove?
a) Intercostal artery
b) Intercostal vein
c) Intercostal nerve
d) All of the above
d
Which part of the vertebrae does the tubercle of each rib articulate with?
Transverse process
Which structure does the central tendon of the diaphragm fuse with?
Pericardium
Approximately which vertebral level is the oesophageal hiatus situated?
T10
What is the innervation of the diaphragm?
Phrenic nerves
Which of the following muscles is active during the inspiratory phase of breathing?
a) Internal oblique
b) Internal intercostals
c) External intercostals
d) Transversus thoracis
c
Transversus thoracis extend from the inferior sternum to the internal costal cartilages of which ribs?
2-6
A patient is undergoing a bronchoscopy for removal of a foreign object. At approximately which vertebral level does the trachea bifurcate?
T4
Which nerve supplies sensory innervation to the mucosa of the trachea?
Recurrent laryngeal nerve
At patient presents with a stab wound to the chest. A open thoracotomy is performed. In which of the following spaces can the superior vena cava be located?
a) Posterior mediastinum
b) Diaphragmatic caval hiatus
c) Entrance to left atrium
d) Superior mediastinum
Superior mediastinum
The superior vena cava receives tributaries from which vessel?
Azygous vein