Thorax Flashcards
Broadly, what do the posterior rami of the spine supply
Extensor muscles of vertebral canal
Varying degrees, the skin
Which muscles do posterior rami supply
Erector spinae
Tramsversospinalis group deep to thoracolumbar fascia
Levator costae
Splenius (and all muscles deep)
What are the branches of the posterior rami (broadly)
Medial and lateral
In upper body, lateral = muscle, medial to skin
Lower body, lateral = skin, medial to muscle
Which spinal segment has NO cutaneous branch
C1
Which spinal segments reach the skin
All thoracic and all sacral
Which posterior rami supply limbs
NONE !!
Broadly, what does the anterior rami supply
All other muscles of trunk & limbs, skin at sides & front of neck & body
What are the rami of brachial plexus
Anterior rami of C5-8, T1
What rami supply muscles of anterior abdo wall
T7-12
What is the lowest spinal nerve to supply anterior abdominal wall
L1, via iliohypogastric & ilioinguinal nerve
What are the branches of the intercostal nerves
Lateral - side
Anterior terminal - front of body wall
What is the fascia of scarpa
Superficial fascia that slides freely over the underlying thoracic wall, rectus sheath & ext oblique aponeurosis
What does the scarpas fascia continue as, and where does it attach
Continues over penis & scrotum as colles fascia, below thighs attached to fascia lata
Where is campers fascia and where does it end
OVER external oblique muscle
Fades out over upper thoracic wall and along midaxillary line
Blood supply of the body wall
Flanks - intercostal, subcostal & lumbar As
Ventral - internal throacic & superior/internal intercostal arteries
Venous drainage of abdominal wall
Above umbi - latearl thoracic vein, ito axillary
Below umbi - greater saphenous vein
Nerve supply of the body wall
Anterior & latearl branches of ventral rami & smaller degree posterior rami
What makes up the skeleton of thoracic wall
12 TV
12 pairs of ribs
CC
Sternum
Which ribs are free
11, 12
What types of joints are in the thoracic skeleton
Costovertebral joint
Costochondrial joint
Sternocostal joint
Interchondral joint
Costovertebral joint features
Head of rib has 2 articular facets that connects to demifacets of vertebral body
- inferior facet of rib against superior costal facet of its own vertebra
- superior facet of rib against inferior costal facet of vertebra above
Costotransverse joint
Articular facet of rib with tip of transverse process of its own vertebra
What reinforces the costotransverse joint
Lateral cT lig
CT lig
Superior CT lig
Costochondral joint features and joint type
Rib with CC - primary cartilaginous joint
What type of joints are the interchondral joints
Joined by small synovial joint
Sternocostal joint - what type of joint is between the 1st cc and manubrium
Primary cartilaginous
Thoracic muscles & neurovascular plane
External intercostal m
Internal intercostal m
Neurovascular plane
Inner layer - subcostal, innermost intercostal, transversus thoracis
Outer layer of thoracic muscles
External intercostal continues anteriorly as
Anterior intercostal membrane
Posterior muscles , outer layer of thorax
Serratus posterior superior and serratus posterior inferior
Serratus posterior superior origin, insertion, features
Origin: spinous process of C6,7; T1,2
Insert: lateral angle rib 2-5
Glistening appearance, with deep dorsal scapular N * vessels run down on post surface b/w it and rhomboids
Serratus posterior inferior origin & insert
Spinous process of T11-12; L1-2
Insert into 4 lowest ribs
Middle layer of thorax
Internal intercostals, replaced posteriorly by posterior intercostals membrane
Inner layer muscle of thorax
Innermost intercostals
Subcostals
Transversus thoracis
Where is neurovascular plane in thorax
B/w innermost IC and internal IC
What is the order of the vessels in the ICS
Vein, artery, nerve
Branches of the intercostal nerves
Collateral branches
Lateral cutaneous branch
Anterior cutaneous branch
Collateral branch of intercostal nerve supplies
Supplies muscle of the space, parietal pleura, rib perisoteum
Lateral cutaneous branch of IC nerve supplies
Pierces IC muscle to supply body wall along mid-axillary line through its anterior & posterior branches
Anterior cutaneous branch of IC nerve suplies
Passes anterior to internal thoracic A and pierces the IC muscle to reach teh skin
What does the lateral cutaneous branch of 2nd intercostal nerve cross to become
Crosses axilla as the intercostobrachial nerve
What is the subcostal nerve and where does it pass to supply…
T12, passes behind the lateral arcuate lig of diaphram into the abdomen below subcostal A+V
Superior (supreme) intercostals artery arise from
Costocervical trunk
Where do the superior IC artery travel to enter the thorax
Pass across the front of the neck of the 1st rib
Where does the superior IC artery supply
Upper 2 spaces
Posterior intercostal arteries supply…
Remaining 9 IC spaces
Anterior intercostal arteries arise from
Internal thoracic (1-6) and musculophrenic A (7-9)
How many intercostal veins are there
1 posterior
2 anterior intercostal veins
Where do the anterior IC veins drain into
Musculophrenic & internal thoracic veins
Posterior intercostal veins drain into…
Lower 8, into the azygos system (right = azygos, hemiazygos & accessory on L)
2,3,and sometimes 4ths into superior intercostal (r => azygos, L => brachiocephalic)
Internal thoracic A arises from
1st part of subclavian A
Termination of internal thoracic artery
Forms superior epigastric and musculophrenic A
Branch of internal thoracic a
2 anterior IC arteries at each ICS
Pericardiophrenic branch
Where does the pericardiophrenic branch run and what does it supply
Runs with phrenic N and supplies branches to the nerve, the pleura, the fibrous & parietal pericardium!
Attachments of suprapleural membrane
Inner border of 1st rib to transverse process of C7
Diaphragm features
Central tendon (note inseparable from fibrous pericardium)
Right and L crus
What FORMS the median arcuate ligament
Where each crus unite in front of each other at T12
What forms the medial arcuate ligament
Thickening of psoas fascia
What forms the lateral arcuate ligament
Thickening of the anterior layer of the lumbar fascia on the front of quadratus lumborum
Where is vena cava opening & contents
T8
IVC
R phrenic N
Where is oesphageal opening & contents
T10
In fibres of L crus
Vagal trunks, oesophageal branches of L gastric
veins
Lymphatics
Where is aortic opening and contents
T12
Aorta, agygos vein & thoracic duct
How does hemiazygos pass through diaphragm
L crus
How do the splanchnic nerves greater, lesser and least enter the diaphragm
Pierce each crus
How does sympathetic trunk enter diaphragm
Medial arcuate lig
How does subcostal N+vessels pass through diaphragm
Behind lateral arcuate lig
How does the L phrenic N pass through diaphragm
Pierce L dome
Blood supply of diaphragm
5 intercostal & subcostal A
R+L inferior phrenic A
Pericardiophrenic & musculophrenic branches
Nerve supply of diaphragm
C3,4,5 (phrenic)
Which main muscles are active in inspiration
Diaphragm
External intercostal
Which main muscle is most active in expiration
Diaphragm
Internal intercostal
Parts of inferior mediastinum
Ant
Middle
Post
Sternal angle level
T4
What space is the anterior mediastinum continuous with
The superior with the pretracheal space
Post mediastinum is continuous with
Superior through the retropharyngeal & paratracheal space of neck up to base of skull
Where does an infection behind the prevertebral fascia track
From neck into superior mediastinum
Ceases at T4
What are things that happen at the sternal angle (in the chest)
CLAPTRAP
Cardiac plexus - superifical * deep
Ligamentum arteriosum
Aortic arch
Pulmonary trunk/pericardium
Tracheal bifurcation
Thoracic duct reaches L side of oesphagus
Recurrent laryngael N L
Azygos enters SVC
Phrenic N
Spinal cord
Boundaries of superior mediastinum
Manubrium, first 4 thoracic verebra
Thoracic inlet contents
oesophagus against T1
Trachea
Arch f aorta
Ligamentum arteriosum
Brachiocephalic V
SVC
Cardiac pleus
Phrenic & vagus N
Branches of aortic arch
Brachiocephalic
LCCA
L subclavian
What nerves cross the arch of aorta
L side by phrenic & vagus nerve
Course of phrenic nerve in the mediastinum
Arch over arch of aorta
Pass infront of lung root
Course of vagus nerve in the mediastinum
Arch over arch of aorta
Behind lung root
What is the relationship b/w L superior IC vein and the phrenic/vagus n
Passes deep to phrenic
Superficial to vagus
What is the ligamentum arteriosum remnant
Ductus arteriosus
What forms brachiocephalic V
IJV and subclavian V
Where does the thoracic duct drain
Into L brachiocephalic V
SVC commences at
1st R CC
What forms the SVC
2 brachiocephalic V
What are the nervous elements of cardiac plexus
SNS
PSNS
Afferent fibres
Small ganglia
What are the 2 parts of the cardiac plexus
Superficial part = in front of ligamentum arteriosum
Deep part = to the R of the ligamentum
In front of trachea and behind aortic arch
Where does the trachea commence and how long is it
C6, bifurcates at T5
10cm long
What is the relationship b/w trachea and vagi
On the R, lies against it, separated from the R lung by pleura & arch of azygos
On the L, the LCCA and L subclavian prevent the pleural and the L vagus nerve from coming into contact
Blood supply of trachea
Inferior thyroid
Bronchial A
Nerve supply for trachea
Vagi
Recurrent laryngeal N
Course of phrenic nerve in the neck
From C4 —> passes down over ant scalene muscle —> cross infront of subclavian A —> dome of pleura —> behind subclavian V
Cross ant to the vagus
Runs through mediastinum anterior to lung root
What vessels lie MEDIAL to the R phrenic N
R brachiocephalic
SVC
Pericardium
What vessels lie MEDIAL to the L phrenic N
L CCA
L SUbclavian
How does R phrenic nerve enter diaphragm
Passes through diaphragm with IVC
How does L phrenic N enter the diaphragm
Pierces diaphragm to the L of pericardium
What is the supply of phrenic N
Motor to diaphragm
Sensory to diaphragm, mediastinual pleura, fibrous pericardial, parietal layer of serous pericardium, central tendon, peritoneum
Relation of R vagus to azygos V
R vagus runs medial to arch of azygos
Relation of vagus to superior intercostal vein
Crosses arch medial to the L superior IC Vein
What plexuses do the recurrent laryngeal nerves give branches to
Deep cardiac plexus
Whole trachea
Adjacent oesophagus
Larynx
Which side of the lung is in contact with the trachea
The R side of the lung (Apex)
The L is separated by L CCA and L subclavian
Contents of anterior mediastinum
Thymus
Sternopericardial lig
Few LNs
Branches of internal thoracic vessels
Blood supply to the thymus
Inferior thyroid
Internal thoracic A
(Corresponding veins)
Broadly the contents of middle mediastinum
Pericardium
Heart
Adjoining greater vessels
Lung roots
Phrenic N
Deep cardiac plexus
What is the fibrous pericardium
Single outer layer that encloses heart & great vessels, fuses with adventitia
What is the serous pericardium
Lines the inside of the fibrous pericardium
Has 2 layers - parietal and visceral
What is between the 2 serous pericardiums
SINUSES
Transverse
Oblique
Nerve supply of pericardium
Fibrous - phrenic
Parietal serous - phrenic
Visceral - insensitive
Blood supply of the pericardium
Internal thoracic A
Pericardiophrenic & musculophrenic branches
Bronchial A
Thoracic A
Venous drainage of pericardium
Azygos system
What is the R border of the heart
RA
Inferior border of the heart
mostly RV, some LV
Apex of heart
LV
Left border of the heart
LV with auricle of LA forming uppermost surface
Sternocostal surface of the heart
Mainly RV, bit of RA + LA
Diaphragmatic surface of the herat
1/3 RV
2/3 LV
Posterior surface of the heart
Entirely of LA
Where is the crista terminalis and what does it do
In the RA, vertical ridge of muscle
Separates pectinate muscle from smooth muscle inside the wall of RA
What are the features of RV
Moderator band of septomarginal trabeculae
Post/ant/septal papillary muscles
Conus arteriosus => PULMONARY TRUNK
What are the cusps of tricuspid valve
Anterior
Posterior
Septal
Cusps of pulmonary trunk
Anterior, right , left
Cusps of mitral valve
Anterior
Posterior
Aortic valve cusps
Posterior
Left
Right
Conducting system of heart
SA node
AV node
Bundle of His
R+L limbs of bundle
Purkinje fibres
Where is SA node
Junction of crista terminalis & SVC
Where is AV node
Within triangle of koch
Base of RA
Where does Right coronary Artery rise
Anterior aortic sinus
Where does the L coronary A arise
L posterior aortic sinus
Course of RCA
Runs down AV groove
Turns backwards at inferior border of the heart
Run posterior
Branches of RCA
Conus artery
SA nodal
R marginal A
Posterior interventricular branch (to AV node)
LCA branches
Circumflex
LAD (Conus branch, marginal branch)
L marginal
Coronary sinus tributaries
Great cardiac vein
Middle
Small
Oblique
Posterior
Where does coronary sinus open
RA - b/w IVC and AV valve
Posterior mediastinum boundaries
T5-12
Pericardium and sloping border of diaphragm
Contents of the posterior mediastinum
Oesphagus
Thoracic aorta
Azygos
Hemiazygos
Accessory hemiazygos
Thoracic duct
LNS
Where does descending aorta start
T4
Branches of thoracic desc aorta
9 pairs of posterior IC arteries
Subcostal A
Bronchial A
Oesophageal vessels
Small pericardial & phrenic branches
Where does oesophagus start
C6, lower border of cricoid cartilage
Where does oesophagus enter the abdomen
Through diaphragm T10
R crus sweeps around oesophageal opening
How long is the oesphagus
25cm
Narrowest parts of oesophagus
Inferior constrictor (cricopharyngeal)
Crossed by arch
L principal arch
Diaphragm
Parts of the oesphagus
Upper
Middle
Lower
Blood & nerve supply of upper oesphagus
Inferior thyroid A
Brachiocephalic V
Recurrent laryngeal N
Blood & nerve supply of middle oesophagus
Oesophageal branches from aorta, bronchial A
Azygos system
Thoracic symp trunk, greater splanchnic nerves, vagus
Blood & nerve supply of lower oesophagus
L gastric A
Oesophageal tributaries => Portal V
Thoracic symp trunk, greater splanchnic
Vagus
Where does the anterior oesophageal trunk arise from
L vagus
Where does thoracic duct commence
Upper end of cisterna chyli at T12
Where does the thoracic duct travel
B/w aorta & azygos V
Where does the thoracic duct in proximity to oesophagus
To the RIGHT, at T5 it moves to the L behind oesophagus
What part of the body does the thoracic duct NOT drain
R upper limb & R half of thorax
What does the azygos vein drains
Collects blood from the thoracic wall & upper lumbar region
The posterior intercostals
Lumbar veins drain into the azygos
What forms the azygos V
Ascending lumbar V
Subcostal V on R side
Where does the azygos V end
In SVC at T4
Where do the hemiazgos veins join the azygos
at T7/8
Where are the hemiazygos V
On L side of bodies of thoracic vertebra
What forms the hemiazygos veins
Union of L ascending lumbar & subcostal V
What does the accessory hemiazygos receive
Bronchial V from L lung
What does the thoracic sympathetic trunk consist of
12 ganglia, lying anterior to heads of ribs
What does each thoracic ganglia
Each ganglion receives a preganglionic white ramus from anterior ramus of corresponding spinal N
Where do the splanchnic (least, lesser, greater) arise from
Lower 8 ganglion
Greater = 5-9th ganglion
Lesser = 10-11th ganglion
Least = 12th ganglion
What types of cell lines pleura
Mesothelium - single layer of flat cells
What are the pleura types & attachments
Parietal = lines ribs, vertebra, diaphragm; attached to inferior surface of suprapleural membrane at thoracic inlet & mediastinul surface of fibrous pericardium
Visceral - adherent to lung
What is the pulmonary lig
Cuff of lung root too big, hangs down and allows expansion of vessels
Arterial supply of pleura
Intercostal A
Internal thoracic A
Musculophrenic A
Venous drainage of pleura
Azygos system
Nerve supply of pleura
Intercostals = costovertebral pleura, periphery of diaphragm
Phrenic = diaphragm domes, mediastinal pleura
Hilum of lung features
Main bronchus
1x pulmonary A
2x pulmonary Veins
Lobes of L lung
Upper
Lower
Lobes of R lung
Upper
Middle
Lower
What is the role of oblique fissure
B/w upper and lower lobes
In both lungs
Horizontal fissure
R lung only, from middle to upper lobe
What is the most superior vessel in the hilum
Pulmonary Artery
What is the most posterior vessel in the hilum
Bronchus
Where does the hilum lie
3rd-4th CC
T5-7
What are the break up of the bronchi from bronchus to resp bronchioles
Bronchus
Lobar bronchi
Segmental bronchi
Bronchioles
Lobular bronchioles
Terminal bronchioles
Respiratory bronchioles
Arterial supply to the lungs
Bronchial Arteries from the aorta
Venous drainage of the lungs
Superficial - azygos/accessory hemiazygous
Deep - main pulmonary vein or into LA
Lymph drainage of the lungs
Along lung surface with the pulmonary vessels to bronchopulmonary or hilar LN
Nerve supply to lungs
Autonomic from cardiac plexus
SNS
Forms a pulmonary plexus
Anterior and posterior to the hilum
Components of sternum
Manubrium
Body
Xiphoid process
What muscles are attached to manubrium
SCM
Sternohyoid
Sternothyroid
What CC articular with manubrium
1st CC
2nd CC
What CCs attach to sternal body
3-7 CC
What muscles attach to body of sternum
Anterior and intercostal membranes
Pec major
Transversus thoracis
Typical rib features
Head
Neck
Tubercle
Shaft
What are features of head of rib
2 articular facets
Lower facet - own vertebra
Upper facet - upper vertebra
Synovial
Features of tubercle of rib
2 facets
Smooth medial - TP of own vertebra
Rough lateral - lateral costotransverse lig
Which ribs are atypical
1st, 11th, 12th
First rib features
Strongest
Broadest
Flattest
Most curved
Single facet on head for T1
Groove for subclavian A
Attachment for middle scalene and anterior scalene
11th rib features
Head, single facet for T11
Short neck
No tubercle
Slight angle
12th rib features
Head, single facet for t12
No tubercle
No angle
No costal groove
