Thorax Flashcards
What is scarpa’s fascia?
What are its boundaries?
Thin strong fascia of the anterior abdominal wall overlying the fattier Camper’s fascia.
BOUNDARIES
- Upper thoracic wall
- Lateral: mid-axillary lines
- Inferior: fascia lata from pubic tubercle to below the inguinal ligament
Turns into Colles fascia over penis and scrotum
p307
Describe the trajectory of the superior intercostal artery.
What does it supply?
Course: from costocervical trunk behind scalenus anterior
Across front of neck of first rib, lateral to sympathetic trunk.
Supplies: upper two intercostal spaces
p315
Describe the drainage of the intercostal spaces
1 posterior intercostal vein
- drains into musculophrenic and internal thoracic veins
2 anterior intercostal veins
- 1st space to supreme intercostal vein
- lower 11 spaces drain into azygos on right,
- space 2-3 to superior intercostal vein
- lower 8 hemiazygos and accessory hemiazygos on left
Describe the course of the superior intercostal vein in relation to the vagus and phrenic nerves.
L) forward over arch of aorta, superficial to vagus, deep to phrenic, empties into L) brachiocephalic
p316
Where are the aortic bodies located and what is their nervous supply?
In adventitial layer under arch of aorta near the ligamentum arteriosum. Supplied by vagal fibres.
What are the borders of the superior mediastinum?
If an infection is in the neck, how is it limited to the superior mediastinum?
thoracic inlet above
horizontal plane through manubriosternal joint
from 2nd costal cartilages to lower T4 and upper T5 vertebral bodies
prevertebral and pretracheal fasciae extend from neck into superior mediastinum. pretracheal fascia attaches to T4 vertebra limiting posterior spread to superior mediastinum.
What are the contents of the middle mediastinum?
pericardium heart great vessels lung roots phrenic nerve (part that passes between pericardium and pleura)
What is the plane between the anterior and posterior mediastinum
At the bifurcation of the trachea, concavity of aortic arch, just above the bifurcation of the pulmonary trunk
Where is the ligamentum arteriosum? Which nervous structure is closely related to it?
From left pulmonary artery to concavity of aortic arch distal to where the subclavian branches off.
Left recurrent laryngeal nerve hooks around it..
What is the nervous and arterial supply of the serous and fibrous pericardium?
SEROUS
Parietal: phrenic
Visceral: not innervated lol
Art: nil
FIBROUS
phrenic nerve
Art: pericardiophrenic and internal thoracic and pericardial (from descending aorta to ventral side)
What are the two sinuses of the parietal pericardium?
TRANSVERSE
aorta and pulmonary trunk above
pulmonary veins below
OBLIQUE
sac between two left and two right pulmonary veins and inferior vena cava
anterior wall: posterior wall of LA
fig 4.18
How is the pericardium attached to other structures?
Fused to central tendon of diaphragm
Fibrous sac connected to upper and lower ends of sternum by sternopericardial ligaments
p335
Fuses to all great vessels EXCEPT IVC (central tendon is in the way)
What are the venae cordis minimae?
Small veins in walls of all 4 chambers of the heart opening directly into their respective chambers. Most frequent in right atrium.
What is the sulcus terminalis? What does it delineate?
Between SVC and R) auricle externally. Internally is a muscle band (crista terminalis) delineating smooth to the right and ridged (pectinate muscles) to the left in the auricle.
Where is the coronary sinus?
Where is the AV node in relation?
What is Koch’s Triangle? (bonus question hehe)
to the left of the fossa ovalis
to the left of the IVC orifice
above the cusp of the tricuspid valve
AV Node is above and to the left of the opening of the coronary sinus (in the interatrial septum) in Koch’s triangle
- septal cusp of tricuspid valve
- anteromedial margin of opening of coronary sinus
- tendon of todaro
p346
Blood supply of each of the SA and AV nodes
SA: R) coronary branch (SA nodal artery)
AV: terminal branch (AV nodal artery), RCA derived in 60% of people
Which heart valves have active competency? What does that mean?
Mitral and tricuspid valves are kept competent by active contraction of papillary muscles that pull on chordae in ventricular systole.
Aortic and pulmonary valves do not have these. Competency is the result of mutual pressure between the distended cups.
What are the surface markers for the valves of the heart?
All lie vertically behind the sternum. Fig 4.26 p344
AP: behind left border at 3rd costal cartilage (pulmonary higher)
MT: behind midline of lower sternum, mitral a little higher and to the left. (4th and 5th approx)
What limits the size of cardiac muscle fibres?
Each cardiac muscle fibre is supplied by a capillary. Oxidative metabolism and mitochondrial capacity prevent hypertrophy up to a certain point.
Increase in size is not met with increase in NUMBER of capillaries.
Describe the structures surrounding the left subclavian artery and what structures separate it from the left brachiocephalic vein. At what thoracic level does it arise?
Posterior: longus colli, oesophagus, thoracic duct
Medial: trachea, left recurrent laryngeal nerve
Separating: cardiac plexus, vagus, phrenic nerve
Arises from T3/4 vertebral disc
Which veins drain coronary system of the heart and where do they empty?
CORONARY SINUS
- posterior AV groove
- opens into RA to the left of IVC
GREAT CARDIAC VEIN
- up interventricular groove, over LA and obliquely into coronary sinus
MIDDLE CARDIAC VEIN
- posteriorly into great cardiac
SMALL CARDIAC VEIN
- anteroinferiorly into lower end of coronary sinus
POSTERIOR
- of left ventricle , into great cardiac vein
OBLIQUE (Marshalls)
- posteriorly over LA into great cardiac vein
ANTERIOR
- small horizontal veins over the RA draining independently
VENAE CORDAE MINIMI
From where do they left and right crus of the diaphragm arise? Which crus encircles the oesophagus?
Left crus L1-2
Right crus L1-3
RIGHT crus encircles
What are the origins and insertions of scalenes?
Anterior scalene: anterior tubercles of transverse processes C3-C6 inserts to first rib
Middle Scalene: Posterior tubercles C2-C6 inserts to first rib
Posterior scalene: posterior tubercles C4-C6 inserts 2nd rib
In principle, the pulmonary arteries and veins follow what pattern in their path through the lungs
Arteries follow airways
Veins are spaced between the bronchi
Describe the route of the subclavian arteries in relation to the scalenes through the neck and what are its main branches?
Passes behind anterior scalene
VITsit Csid and D
- vertebral
- internal thoracics
- thyrocervical trunk
- suprascapular
- inferior thyroid
- transverse cervical
- costocervical trunk
- superior intercostal
- deep cervical
- dorsal scapular
Describe the course of the azygous vein in relation to
- the vertebral column
- the trachea
- the SVC
Up along right side of vertebral column, over the trachea and into the superior vena cava, just before it enters the pericardium
Why is the septum transversum important?
Origin of the fibrous pericardium and central tendon
Embryologically marks the location of the liver
Describe the course of the right phenic nerve in the thorax
AS FAR LATERAL AS POSSIBLE
- Arise C4
- down over anterior scalene across dome of pleura behind subclaviain vein
- in front of lung root
- lateral to VENOUS structures (r brachiocephalic vein, SVC, right atrium, IVC)
- pierces diaphragm with vena cava
Describe the course of the left phrenic nerve in the thorax
AS FAR LATERAL AS POSSIBLE
- Arise C4
- down over anterior scalene over dome of pleura
- lateral to L) common carotid and left subclavian arteries
- crosses arch laterla to superior intercostal vein
- over pericardium towards apex, piercing just to left pf pericardium
What is the nerve supply of the diaphragm?
The PHRENIC nerve
“C3, 4, 5 keeps the diaphragm alive”
MOTOR
Anterior, lateral and posterior branches of left and right phrenic nerves
- R) crus to the LEFT of the diaphragm supplied by left phrenic
SENSORY
- mostly phrenic, outermost portion by intercostal afferents
What is the course of the right vagus nerve in the thorax.
As MEDIAL as possible
- in contact with trachea
- deep to arch of azygous
- behind lung root (gives off pulmonary plexus branches)
- enter into oesophageal plexi on surfaces of lower oesophagus
What is the course of the left vagus nerve in the thorax?
As MEDIAL as possible
- separated from trachea by great arteries from arch of aorta
- crosses arch deep to left superior intercostal vein
- gives of contribution to pulmonary plexus
- enter into oesophageal plexi on lower surfaces of oesophagus
Where do the right and left recurrent laryngeal nerves come off?
What do they supply?
LEFT: around ligamentum arteriosum, up on right side of aortic arch ascending between trachea and oesophagus
RIGHT: at root of neck, hooks around right subclavian artery
SUPPLY
- trachea
- oesophagus (above root of lung)
- cardiac plexus
- muscles of larynx except cricothyroid
- larynx below level of vocal cords
Where are the superficial and deep portions of the cardiac plexus? From where are the sympathetic and parasympathetic fibres derived?
sympathetic/parasympathetic/afferent fibres
SUPERFICIAL: lies in front of ligamentum arteriosum and becomes continuous with deep
DEEP: lies to the right of ligamentum arteriosum in front of left bronchus at bifurcation of pulmonary trunk
SYMPATHETICS: postganglionic from cell bodises in cervical and upper thoracic ganglia, preganglionic from lateral horn of upper 5-6 Thoracic segments
VAGAL: preganglionic from bodies in dorsal motor nucleus + nucleus ambiguus
What is the nerve supply to the lungs?
parasympathetic afferents: vagus
parasympathetic efferents: vagus
these mediate cough reflex and motor to smooth muscle of bronchi and pulmonary arterioles
Sympathetic fibres relay in T1-T4: dilate pulmonary arterioles to bronchi
What is the stellate ganglion? Where is it?
First thoracic sympathetic ganglion fused with inferior cervical canglion to form cervicothoracic ganglion
Overlying neck of first rib posteromedial to the vertebral artery
Where does the pulmonary trunk bifurcate in relationship to the bifurcation of the trachea?
inferior and to the left of the bifurcation of the trachea
What structures pass under the MEDIAN arcuate ligament?
- Aorta
- Azygous vein
- thoracic duct`
What structures pass under the MEDIAL arcuate ligaments?
- sympathetic trunk
(greater, lesser and least splanchnic nerves pierce each crus
What are the anterior relations to the neck of the first rib from medial to lateral
Anteriorly the neck is related from medial to lateral to the
- sympathetic chain
- first posterior intercostal vein
- the superior intercostal artery
- first thoracic nerve
p. 315 fig 4.5
