Anatomy - Thorax Flashcards
For the thoracic wall
Openings: Skeleton parts: Joints: Intercostal spaces: Muscles:
Openings: superior and inferior thoracic apertures
Skeleton: sternum, twelve pairs of ribs, twelve thoracic vertebrae
Joints: intervertebral discs, costovertebral, sternocostal, sternoclavicular, costochondral, interchondral joints
Intercostal spaces: intercostal vein, artery, nerve
Muscles: intercostal muscles, (external, internal, innermost), transversus thoracis, subcostals, levatores costarum, serratus posterior superior, serratus posterior inferior muscles
The attachments of diaphragm can be divided into?
The attachments of diaphragm can be divided into peripheral and central attachments.
It has three peripheral attachments:
Lumbar vertebrae and arcuate ligaments.
Costal cartilages of ribs 7-10 (attach directly to ribs 11-12).
Xiphoid process of the sternum.
The parts of the diaphragm that arise from the vertebrae are ? in structure, and are called?
The parts of the diaphragm that arise from the vertebrae are tendinous in structure, and are called the right and left crura.
Right crus – Arises from? Some fibres from the right crus surround what opening
Left crus – Arises from?
Right crus – Arises from L1-L3 and their intervertebral discs. Some fibres from the right crus surround the oesophageal opening, acting as a physiological sphincter to prevent reflux of gastric contents into the oesophagus.
Left crus – Arises from L1-L2 and their intervertebral discs.
The pathways through the diaphragm and their vertebral levels:
What are the contents?
3 Hiatuses:
1) Cava hiatus (T8): Vena Cava, terminal branches right phrenic nerve
2) Oesophageal Hiatus (T10): R+L Vagus nerve, Oesophageal branches of Left gastric artery and vein
3) Aortic hiatus: Thoracic duct, azygous vein, Aorta.
Trick for remember ing the level of diaphragm hiatuses?
A tip for remembering the vertebral levels: vena cava has eight letters (T8), oesophagus has ten letters (T10) and aortic hiatus has twelve letters (T12).
Functions of the trachea and bronchi
Large airway conduits for gas exchange.
Pathway of expectoration
The trachea begins
At the inferior edge of the hypopharynx, which is the inferior edge of the cricoid cartilage. At the level of C6.
The trachea ends at:
In the thorax at the level of the sternal angle (T4) at the carina which is the bifurcation of the trachea.
How much does the carina move with deep inspiration?
Movers from T4 to T6
How big is the carina?
12cm long, 2.5cm wide
Describe the trachea
Large airway conduits for gas exchange.
Pathway for expectoration
12cm long, 2.5cm wide fibrocartilagenous tube, whose structure is maintained by “u shape” bars of hyaline cartilage.
begins at the inferior edge of the hypopharynx, which is the inferior edge of the cricoid cartilage. At the level of C6. In the thorax at the level of the sternal angle (T4) at the carina which is the bifurcation of the trachea.
Carina moves between T4 and 6 on deep inspiration.
Relations of the cervical trachea
Superior: Hypopharynx, inf edge cricoid, isthmus of thyroid (anterior superior)
Anterior: sternothyroid and sternohyoid
muscles, anterior jugular veins and JUGULAR VENOUS ARCH
Posterior: oesophagus, recurrent laryngeal nerve, Cervical vertebrae.
Lateral: Carotid sheath, lobes of thyroid
Relations thoracic vertebrae:
Anterior: sternum, origins of right brachiocephalic and left common carotid arteries, left brachiocephalic veins
Posterior: oesophagus left recurrent laryngeal nerve
Left: aortic arch, left common carotid, left subclavian artery, left vagus, left phrenic and recurrent laryngeal n, pleura
Right: azygos vein, right vagus and pleura
The lining of the trachea:
Respiratory epithelium:
Ciliated PSEUDOstratified columnar epithelia, w/mucous glands (goblet cells)
Mnemonic for segments of the lung. State which bits are basal and which lingular.
ALSO applies to?
Right Lung:
A PALM Seed Makes Another Little Palm
- Capitals are upper and middle: APA = upper Apex, post, ant. LM = middle, lat and med
- lower case is lower lobe: everything but superior has basal in thename - i.e Lateral basal segment
Left Lung:
ASIA ALPS
ASIA = UL + Lingular (Sup and Inf LINGULAR segments)
ALPS = LL = Superior segment, then all the rest have BASAL in their name, i.e Lateral basal Segment
The above also applies to bronchi
Relations of the right and left main pulmonary veins (also their tibutaries are?)
The right main pulmonary veins: passes the right atrium and superior vena cava inferiorly; the left in front of the descending thoracic aorta.
What does the aortic arch loop over?
1) Left main bronchus or bifurcation
2) Bronchial arteries (which emerg from the anterior surface of the aorta just before the arch)
3) bifurcation of pulmonary trunk
Main branches of aortic arch
Right: branchiocephalic trunk (i.e needs to be simple because Right and left brachiocephalic kinda in the way)
Left (proximal to distal): Left common carotid, left subclavian artery
what nerve closely associates with the aortic arch?
The left vagus.
On the right the vagus travels over the subclavian proximal to the bifurcation, giving of a branch of the recurrent laryngeal which loops under and goes back up
1st branch of left brachiocephalic vein?
right thyroid vein (this can come off the bifurcation though)
The highest lymph nodes of the thorax are stations?
Where are they?
The next
The next
The next
The trachial nodes are Left Right, except 3 which are Ant Post. Highest - upper - retro - lower.
1 R and 1L “Highest mediastinal nodes”
Superior trachea, just superior to origin of right subclavian
2R and 2L Left upper paratracheal - above arch
3A and 3P are anterior and posterior trachial (3A is prevascular behind bifurcation of SVC.
4R and 4L are lower paraterachial
The next groups of thorax nodes after the trachea (but not the bronchi)
Rule: All nodes not paired (i.e. no r/L, A/P) number from 1-8 going down trachea, 8 paraeosphageal. 5 = subaortic 6 = Paraaortic 7 = Subcarinal 8 = paraeosphageal
After the paraeosphageal nodes, what comes next?
All are paired R+L 9 = pulmonary lig nodes R+L then 10 is hilar nodes at the main bronchus (this are adjacent to 7 = subcarinal) 11 Bifurcation = interlobular nodes 12 = lobular 13 = segmental 14 = subsegmental nodes
Branches of the left main bronchus
Left main becomes Left superior lobular and left inferior lobular - The ASIA ALPS
Right main: the superior, middle and inferior lobular branches, then A PALM Seed Makes Another Little Palm
Sensory innervation of the trachea:
Recurrent laryngeal nerve
Describe the right main bronchi:
4cm long
wider and more vertical than left bronchi
Extends from carina to hilum of lung
Gives of superior lobular branch before entering the lung, where divides into middle and inferior.
Relations:
- Superio-inferior to right pulmonary artery
- Azygous crosses over it
Describe the LEFT main bronchi:
6cm long, thinner than left and runs more horizontally
Extends from carina to hilum where it dives into inferior and superior lobular branches.
Relations:
Passes under the arch of the aorta, anterior to the descending part. Anterior to eosophagus
Innervation of the bronchi?
Left and right vagus
Venous supply to bronchi:
Right: Bronchial veins to azygous
Left drain to accessory hemi-azygous
How do the right and left main bronchus differ in terms of branching?
The main bronchus is short, quickly giving off a a superior lobular branch after which it becomes the intermediate segment. The left main bronchus is relatively longer, and does not have and intermediate branch.
Describe the heart:
Pyramidal shaped hollow muscular fist size organ with apex directed anteriolaterally to the left. Apex, base and three surfaces: Sternocostal Diaphragmatic Pulmonary Positioned in middle mediastinum Covered in fiberous pericardial sac Function is as a pump to return deoxygenated blood from the venous system and recirculate oxygenated blood returning from the pulmonary veins
Surfaces of the heart
Apex, base
Diaphragmatic surface
Sternocostal
Pulmonary
The base of the heart is mainly formed by?
Why
Mainly formed by left atrium
This surface dominated by the pulmonary veins
Sternocostal surface of the heart is formed by:
Right atrium and ventricle
Diaphragmatic surface of the heart is formed by:
Mainly left ventricle, partly right ventricle
The apex of the heart is formed by? and is inferior to?
Formed by left ventricle
Lies behind 5th intercostal space in the midclavicular line
Boarders of the heart
Right border –Right atrium
Inferior border - Left ventricle and right ventricle
Left boarder - right atrium
Superior - Right and left atrium and great vessels
What sulcus (aka?) runs transversely around the heart? • represents the wall dividing the? • contains important vasculature, such as?
What are the other 2 important sulci?
Coronary sulcus (or atrioventricular groove) runs transversely around the heart?
• represents the wall dividing the atria from the
ventricles
• contains important vasculature, such as the right
coronary art
Other sulci:
Anterior and posterior interventricular sulci
The pericardial sinuses are formed by?
what are they called?
The pericardial sinuses are formed by folds of pericardium around the great vessels.
Transverse pericardial sinus: Run transversely above the pericardial fold for the pulmonary veins, and so superior to the left atrium. Runs posterior to the ascending aorta and pulmonary trunk
Anterior to SVC
Oblique pericardial sinus: Blind ended sac on base/posterior surface, space within fold for pulmonary arteries.
Origin of aorta:
1st segment. Branches in daughter branches:
Arises from the AORTIC ORRIFICE of the left ventricle
1st segment is the ascending aorta which lies within the pericardial sac.
Left and right coronary arteries at aortic sinuses, just distal to the valve:
LCA: Left anterior descending (1st branch), and left marginal. After which LCA becomes the CIRCUMFLEX
RCA: Right marginal (1st branch), posterior INTERVENTRICULAR artery
The thoracic aorta has how many segments?
Describe the final 2:
3
1) Arch: begin as ascending aorta leaves pericardium
Ligamentum venosum internal arch to bifurcation of pulmonary artery.
Brachiocephalic trunk
Left common carotid
Left subclavian
2) Descending aorta: Posterior intercostal arteries.
From sup to inf: Bronchial, mediastinal, pericardial and sup phrenic.
The caval hiatus is at what level and passes though what structure in the diaphragm?
Vena Cava (8 letters) passes the central tendon (caval hiatus) at T8
Course of the superior vena cava:
Formed by the confluence of the left and right brachiocephalic trunks in the superior anterior mediastinum at about the level of T3.
Then vertically downwards behind first intercostal space and receives AZYGOUS vein just before it pierces pericardium opposite right second costal cartilage and its lower part is intrapericardial.
Ends in the upper and posterior part of the sinus venarum of the right atrium, at the upper right front portion of the heart.
Tributaries of the brachiocephalic veins
At what anatomical point is the confluence?
Behind the sternoclavicular joint the INTERNAL JUGULAR and SUBCLAVIAN Vein join. The Left then travel obliquely across the midline.
The only difference in tributaries is that the left receives the superior intercostal vein.
Other tributaries:
L/R inferior thyroid vein
posterior intercostal veins of the 1st intercostal space, thymic veins,
Internal thoracic veins
What minor vein groups does the SVC receive?
Mediastinal veins
Oesophageal veins
Pericardial veins
Describe the course of the thoracic duct:
Origin is the cistern chyli immediately enters the thorax/posterior mediastinum via the aortic hiatus at T12.
Thin walled, and dull white, the duct ascension the posterior mediastinum along the anterior aspect of the lower 7 thoracic vertebral bodies. Crossing to the left side between T4 and T6, posterior to the oesophagus.
Receives branches from the middle and superior intercostal spaces of both sides through several collecting trunks. Also receives branches from posterior mediastinal structures.
Typically empties into the venous system near the union of the left sublvian and jugular vein (can terminate in either).
The thoracic duct drains everything but?
The right forequarter, which is drained by the right thoracic duct.
Subsections of the mediastinum:
Superior
Anterior, middle, posterior
The boarder between the superior mediastinum and the rest:
The lower boarder of T4/Manubrium sternum
Contents of the superior mediastinum:
Thymus
Oesophagus
Trachea (bifurcation is below inf border)
Vessels: Arch of aorta and its left and right branches. SVC and its tributaries (and the tributaries of the left and right brachiocephalic)
Thoracic duct
Nerves: L/R Vagus nerves, recurrent laryngeal nerve, L/R phrenic
Muscles: Sternohyoid and sternothyroid muscles
( arise from posterior surface of manubrium). Longus
colli
Border of the anterior mediastinum:
Roof: Superior mediastinum
Ant: Sternum, transversus thoracis
Post:Anterior pericardium
Floor: Diaphragm
Contents of anterior mediastinum:
In children the thymus extends this far
Fat, lymphatics
Loose connective tissue, the sternopericardial ligaments
Describe the thymus:
Most ant structure in mediastinum
Primary lymphoid organ located in the lower neck and
After puberty it undergoes gradual involution and is
replaced by fa
Contents of the middle mediastinum:
Pericardial sac: Heart, root/ascentending aorta, truck and origins of cardiac vessels.
Lung roots
NERVES!! Phrenic nerves and deep part of the cardiac plexus
Describe the fibrous pericardium:
outer layer, fused with adventitia of great vessels and blended with the central tendon of diaphragm.
Phrenic nerves lie on fibrous pericarduim
Mediastinal pleura adherent to it
Connected to posterior sternum by weak ligaments
Supplied by internal thoracic arteries and veins
Describe the serous pericardium
Inside fibrous pericardium
Covers entire heart and
forms epicardium
Visceral and parietal layers
Transverse and oblique sinus overdose of heart denied by reflections around the pulmonary veins.
Nerve supply to to pericardium:
Arterial and venous supply:
phrenic nerve except visceral layer of serous
pericardium which is insensitive
Blood supply:
Internal thoracic, bronchial art and thoracic aorta
Pericardial Veins to azygous system
Lymphatic drainage of the middle mediastinum is via?
Via tracheobronchial nodes:
2L+R, 3A+P, 4L+R
Relations of the posterior mediastinum:
Roof: Sup mediastinum (inf border T4) Floor: diaphragm Ant: Posterior fibrous pericardium Post: Vert bodies T5- T12 Lateral: Left and right mediastinal pleura
What happens to the position of the oesophagus in the posterior mediastinum?
Moves from right to the left as it descends, also moves anteriorly
Contents of the posterior mediastinum
Oesophagus
Vessels:
- Descending aorta: branches = bronchial (usually 1 or 2 paired), oesophageal (~2 unpaired), sup.phrenic (paired branch at hiatus).
- Azygous system
Thoracic duct: posterior to aorta (remember it moves to left in sup mediastinum)
Sympathetic trunks; give rise to the lower thoracic
splanchnic nerves
The azygous vein is formed by?
Where
Formed by right subcostal and right lumbar vine immediately before entering the thorax via aortic hiatus
The hemiazygous vein is formed by?
Where?
Where does it join the azygous vein?
The left subcostal and lumbar veins.
Then enters thorax via the left crus.
Joins the azygous vein by turning right at T8
The accessory hemiazygous vein is formed by?
Where does it join the azygous SYSTEM?
Formed by intercostal veins 4-8.
Joins directly to azygous vein at T7
Describe the oesophagus:
A 25cm pink, fibromuscular tube. Cervical, thoracic and abdominal portions:
Extending from the larynx pharynx, passing from the neck to superior, then posterior mediastinum to exit the diaphragm via the oesophageal hiatus at T9 to join the stomach. Can be compressed by diaphragm, aortic arch and left main bronchus.
Function: conduit for injected food in the aeordigestive tract, along with secretions to reach the stomach.
Divisions of the oesophagus, and describe the 1st part:
Approx how long is each part?
1) Cervical: starts at inf boarder of hypopharynx (C6) anterior vertebral bodies and posterior to trachea, lateral to carotid sheaths and the recurrent laryngeal nerves that run in the trachea-oesophageal grooves bilateral.
2) Upper thoracic
3) Middle thoracic
4) Lower thoracic
5) Cardia
All are 5 cm long, except Lower thoracic = 10, cardia = 3.
Exact location of the exit of the oesophagus from the thorax:
At the level of T9, exists via the right crus of oesophageal hiatus.
The oesophagus is surrounded by what plexus? Which nerves contribute to it?
Surrounded by oesophageal plexus: parasympathetic fibres from vagal nerves, sympathetic from thoracic sympathetic trunks.
Describe the upper oesophageal sphincter:
Anatomical sphincter (unlike lower which is physiological), striated muscle sphincter
At the junction between the pharynx and oesophagus
Produced by the cricopharynxgeus muscle.
Normally constricted to prevent the entrance of air into the oesophagus
Relations of the thoracic oesophagus (for each position list sup to inf):
Superior: cervical oesophagus
Ant: Trachea, LEFT Bronchus, posterior fibrous pericardium, crus of diaphragm
Post: Vertebral bodies, thoracic duct, azygous vein, mor inferiorly the descending aorta
Left Lateral: L.Vagus nerve, In the sup mediastinum the aortic arch then descending aorta
Right: Pleura
Describe the abdominal oesophagus:
In the abdomen, the oesophagus descends for 1 – 2 cm and then enters the cardiac orifice of the stomach
to the left of the T11 vertebra.
***lies on the posterior surface of the left
lobe of the liver, and is related posteriorly to the left crus of the diaphragm.
What connects the oesophagus to the border of the oesophageal hiatus
Phrenoesophageal ligament connects the abdominal oesophagus to the border of the oesophageal hiatus
Arterial supply to oesophagus:
1) Upper 1/3rd: inferior thyroid artery (Br of thyrocervical trunk)
2) Middle 3rd: Oesophageal arteries from descending aorta.
3) Lower 3rd: Oesophageal branches of left gastric
Venous supply to oesophagus:
1) Upper 1/3rd: Inferior thyroid veins
2) Middle 3rd: oesophageal branches of Azygous
* ***** 3) Lower 3rd:
i) Portal: branches to via left gastric vein portal vein
ii) Systemic: Azygous vein
(i. e oesophageal varices)
Lymphatic drainage of the oesophagus:
1) Upper 1/3rd: Deep cervical and supraclavicular
2) Middle 3rd: Superior and posterior mediastinal nodes (paratrachial nodes 2-4)
3) Lower 3rd: left gastric and coeliac nodes.
Describe the layers of the oesophagus:
1) Adventitia
2) Muscular layer:
- External longitudinal. Upper 1/3rd treated (voluntary control), bottom 3rd smooth muscle, middle 3rd is a mix
- Internal circular layer
3) Submucosa
4) Mucosa: Non-keratinised stratified squamous epithelium
Describe the lower oesophageal sphincter:
To the left of T12 vert body, marked by a change from eosophageal mucosa to gastric.
Physiological sphincter formed by 4 phenomena:
1) Acute angle of entry to stomach
2) Intra-abdominal section compressed when stomach full
3) Lumen partial occlude by gastric folds
4) Right crus has “pinch-cock” effect
Describe the pleura:
General: – Serous membranes lining lungs and thoracic cavity. – Permit respiration Composed of parietal and visceral layers Thicker than visceral plaura – Suddivided according to contact with – • Mediastinal • Cervical • Costal • Diaphragmatic • Visceralpleura – Covers outer surface of lungs – Extends into interlobar fissures
Pleura histology:
The visceral pleura is composed of a thin, loose connective tissue.
The Parietal surface is lined by specialized squamous-like cells, mesothelium.
The connective tissue of the visceral pleura is contiguous with the connective tissue of the pulmonary lobular septae that course through the pulmonary parenchyma.
Describe the nerve supply to the pleura:
Trick question: Visceral and parietal have different innervation.
Parietal: Highly localised sensation (pain, pressure, temp) via intercostal and phrenic nerves
Visceral: Only sensitive to stretch, via pulmonary plexus (from symp trunk and vagus)
Arterial supply to the pleura
Bronchial arteries from descending aorta
Describe the breasts
Paired skin covered structures located on the pectoral chest. More prominent in females after puberty, the rounded shape of the breast can be broken in body and tail parts.
In females the enlarged body contains the lobulated mammary glands for lactation.
Centered over the body, each breast has circular pigmented areolar containing numerous sebaceous glands, and in the centre the nipple largely composed of smooth muscle, in females this is larger, with a sinus connection to the ducts of the mammary glands.
It extends horizontally from the lateral border of the sternum to the mid-axillary line. Vertically, it spans between the 2nd and 6th intercostal cartilages. It lies superficially to the pectoralis major and serratus anterior muscles.
Borders of the boob:
Medial: Later border of the sternum
Lateral: mid-axillary line.
Superior and inf: 2nd and 6th intercostal cartilages.
Posterior: Pectoralis major and serratus anterior muscles.
Key anatomical boob structures:
The ducts (from lobule to nipple): Lactiferous duct->lactiferous sinus -> Lactiferous sinus (in nipple)
Lobules of mammary gland
The outside: Skin, areolar, nipple
Support: Suspensory ligaments (attached to pectoral fascia), fatty tissue
Behind: Reteromammary space, pectoral fascia, pec maj
Lymphatic drainage of the boob:
There are three groups of lymph nodes that receive lymph from breast tissue – the axillary nodes (75%), parasternal nodes (20%) and SCF (5%).
The skin drains to Skin – drains to the axillary, inferior deep cervical and infraclavicular nodes.
Nipple and areola – drains to the subareolar lymphatic plexus.
The axillary nodes are 5 groups
Describe the axillary lymph nodes
There are 5 groups, lateral, anterior, posterior (subscapular), central and apical nodes.
The apical nodes are the final common pathway for all of the axillary lymph nodes.
Lateral (humoural) are posteromedial to axillary vein (1st nodes in chain from upper limb)
*** Pectoral (anterior): inferior border of pectoralis minor, near lateral thoracic vessels. Drains to central and directly to apical. These drain the boob and skin and muscles of the supraumbilical anterolateral body wall, breast
Posterior (sub scapular): along subscapular vessels on inferior margin of the posterior axillary wall
Central: In the fatty central tissue of axilla. Drain to apical nodes.
** Apical: posterior and superior to pectoralis minor, towards the axillary vein. Drains into subclavian trunk (may drain into jugulosubclavian venous trunk, subclavian vein, jugular lymphatic trunk, right lymphatic duct (left into thoracic duct), inferior deep cervical nodes)
