Anatomy of the Thorax Flashcards

Question

## Footnote **Define the pericardial cavity**

Answer 1

The potential space between the parietal pleura and visceral pleura of the pericardium

Answer 2

**The pericardial pleura is reflected around the roots of the great vessels** -the parietal pleura becomes continuous with the the viscera pleura / epicardium Marked on the posterior surface by: **OBLIQUE sinus:** bound by IVC and four pulmonary veins and forms recess between left atrium and pericardium **TRANSVERSE sinus:** SVC and left atrium behind and the aorta and the pulmonary trunk in front (forms gap between veins and arteries)

Answer 3

OBLIQUE sinus: bound by IVC and four pulmonary veins and forms recess between left atrium and pericardium

Answer 4

TRANSVERSE sinus: SVC and left atrium behind and the aorta and the pulmonary trunk in front (forms gap between veins and arteries)

Answer 5

The herat is situated in the **middle of the inferior mediastinum** The inferior mediastinum is defined by the **T5 - T12 vetrebral bodies** The middle inferior mediastinum begns at the fribous pericardium

Answer 6

**Rigth border = right atrium** **Left border = left venticle** and left auricular appendage **Inferior border = Mianly right ventricle** and lower rigth atrium with the apex of the left ventricle **Apex = left ventricle**

Answer 7

**Anterior surface: mainly right ventricle**, separated from **right atrium** by atriovententricular groove, separated from the **left ventricle** by the anterior interventricular grrove **Inferior (diaphragmatic) surface: left ventricle** and **rigth ventricle** separatesd by the posterior interventricular groove **Base / Posterior surface**: mainly **left atrium a**nd some of right atrium (quadrilateral in shape)

Answer 8

1. **SVC** in the upper and posterior part 2. **IVC** in the inferuir part 3. **Coronary sinus** in the lower part 4. **Anterior cardiac vein** in the anterior part (drains much of the anterior surface of the heart)

Answer 9

**Musuclar ridge** running almost **vertically down from the SVC to the IVC** Indicated on the outer surface of the heart by a shallow groove - the **sulcus temrinalis** Separates the **smooth walled posterior atrium** derived from the **sinus venosus** from the **rough-walled anterior atrium w**hich is derived from the **fetal atrium**

Answer 10

The s**ulcus terminalis is a shallow groove** on the exterior surface of the heart that marks the inner crista terminalis **crista terminalis**- a muscular ridge running from the SVC to the IVC in the **right atrium**

Answer 11

* musculi pectinati* * =* pectinate muscles **Trabeculations** in the rougth anterior portion of the atrium (derived from fetal atrium) which are prodiuced by parallel columns of muscles

Answer 12

Joined by the right atrium via the vertically orientated **tricuspid valve** Houses the **pulmonary valve** which leads to the **pulmonary trunk** **Infidibuloventricular crest** is a muscular ridge that separates the inflow and outflow tracts of the right ventricle

Answer 13

Infidibuloventricular crest is a muscular ridge that separates the inflow and outflow tracts of the right ventricle **Lies between the atrioventricular and pulmonary orifices**

Answer 14

**Infundibulum (also known as conus arteriosus)** is a conical pouch formed from the upper and left angle of the right ventricle in the chordate heart, from which the pulmonary trunk arises.

Answer 15

**Irregular muscular elevations** that mark the inflow path of the _rigth ventricle_ -from which, the papillary muscles project into the lumen and attach to the free borders ofthe tricuspid valve via the **chordae tendinae**

Answer 16

**Chordae tendinae:** tendon-resembling fibrous cords of connective tissue that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart They arise from the **trabeculae carnae**

Answer 17

During systole the papillary muscles shorten --\> pull upon the **chordae tendinae** --\>**prevent prolapse of the tricuspid valve into the atrium** Ischaemic injury to the papillary muscles can precipitate acute valve failure and subsequent acute heart failure

Answer 18

Moderator band: a **muscular band that crosses the ventricular cavity** from the _interventricular spetum to the anterior wall_ Contains: **RIGHT** branch of the **ATRIOVENTRICULAR BUNDLE** and carries it to the **RIGHT VENTRICLE**

Answer 19

**= outflow tract of the rigth ventricle** Smmoth-walled, directed upwards and to the tight toward sthe pulmonary trunk

Answer 20

1. Smaller vs the right atrium 2. Thicker walled 3. **Four pulmonary veins** open into the posterior aspect 4. **Fossa ovalis**: shallow depression on the septal surface of the left atrium 5. Main part of the atrium is msooth walled 6. **Auricular appendage** contains ridges from the undelrying pectinate muscles

Answer 21

1. Communicates with the left atrium via the **m****itral valve: bishops mitre** - attached to papillary muscle via the chordae tendinae 2. Marked by thick trabeculae carnae 3. The only smooth part of the left ventricle is teh **fibrous vestibule** below the *aoritc orifice*

Answer 22

* Separates the left atrium and teh left ventricle * Two leaflets: bishops mitre * **Large anterior leaflet** * **Smaller posterior leaflet** * Attahced by chordae tendinae by the papillary muscles

Answer 23

* Circular opening, in front and to the right of the left atrioventricular orifice * Situated above **aortic vestibule** which is smooth-smalled * **Three semi-lunar cusps = aortic valve** * Above which there are **_three_** sinuses - **the aortic sinuses**

Answer 24

**Aortic sinus = dilitations in the ascending aorta** 1. Anterior aortic sinus: gives off **rigth coronary artery** 2. Left posterior aortic sinus: gives off the **left coronary artery** 3. Right posterior aortic sinus: non-coronary sinus During **diastole** turbulent blood forms inthe sinuses which helps to shut the aortic valve and also perfuses the coronary arteries

Answer 25

Located in the upper part of the **crista terminalis** (muscular ridge from SVC to IVC in rigth atrium)

Answer 26

* Located in the **atrial septum immediately above the opening of the coronary sinus** * Bundle of His divides at the junction ofthe **membranous** and **muscular** parts of the **interventricular septum**

Answer 27

1. **Sinoatrial node** is located in the upper part of teh crosta terminalis, just to the right of the opening of the SVC and **initiates** the electrical impulse 2. From here, the impulse spreads through the atrial musculature to the atrioventricular node 3. The **atrioventricular node** is lcoated in the **atrial septum** just above the coronary sinus 4. It continues as teh Bundle of His which divides at the junction of the **membranous** and **muscular** parts of the **interventricular septum** 5. The rigth and left branches runs immediately beneath the endocardium

Answer 28

= ANTERIOR AORTIC SINUS

Answer 29

= LEFT POSTERIOR AORTIC SINUS

Answer 30

1. Arises from the anterior aortic sinus 2. Passes forwards (anteriorly) between the **pulonary trunk** and the **right atrium** 3. Descends in the right section of the **atrioventricular groove** 4. At the **inferior** border of the heart it continues along the **atrioventricular groove** to anastomose with the **LEFT CORONARY ARTERY** at the **posterior interventricular groove** **Branches** * Gives off **marginal artery** along the lower border of the heart * Gives off **posterior interventricular branch** at the posterior aspect which runs forward in the **interventricular groove** to anastomose near the apex with corrosponding branch of LCA

Answer 31

1. Arises from the **left posterior aortic sinus** 2. Passes behind and then to the left of the **pulmonary trunk** 3. Reaches left part of the **atrioventricular groove** in which it runs laterally around the heart as the **cirucmflex artery** 4. **Circumflex artery** reaches the posterior interventricular groove **Branches** * **Anterior interventricular artery aka _Left Anterior Descending_**: given off within 2.5cm of its origin, supplies the anterior aspect of both the left and right ventricles, passes around the apex of the heart to anastomose with the **posterior interventricular (or posterior descending)** branch of the RCA * This bifurcation into LAD and circumflex can occassionalyl be a trifurcation with an additional artery called the **ramus** or **intermediate** artery being given off * The circumflex gives off the **left marginal artery**

Answer 32

**Branches** Gives off **marginal artery** along the lower border of the heart and continues as the rigth coronary artery **In 85% of people it then gives off the posterior descnding artery (****posterior interventricular branch)** at the posterior aspect which runs forward in the interventricular groove to anastomose near the apex with corrosponding branch of LCA

Answer 33

**Left main stem -**-\> **left anterior descending (** anterior interventricular artery) and **left circumflex** Left anterior descending (anterior atrioventricular artery) --\> diaganol artery **Left circumfle**x --\> left merginal artery **Anterior interventricular artery aka Left Anterior Descending**: given off within 2.5cm of its origin, supplies the anterior aspect of both the left and right ventricles, passes around the apex of the heart to anastomose with the posterior interventricular (or posterior descending) branch of the RCA This bifurcation into **LAD and circumflex** can occassionalyl be a trifurcation with an additional artery called the **ramus or intermediate artery** being given off The **circumflex gives off the left marginal artery**

Answer 34

1. **Coronary sinus** Great cardiac vein Middle cardiac vein Small cardiac vein Oblique vein 2. **Anterior cardiac veins** 3. **Venae cordis minimi**

Answer 35

* The coronary sinus lies in the **posterior atrioventricular groove** * It opens up into the **rigth atrium** just to the left of the IVC * Recieves 1. **Great Cardiac Vein** (fed by the anterior interventricular vein): in the **anterior atrioventricular groove** 2. **Middle Cardiac Vein**: in the **inferior atrioventricular groove** 3. **Small Cardiac Vein** fed by the rigth marginal vein: in the lower rigth border of the heart accompanying the right marginal artery 4. **Oblique Vein:** descends obliquely in the posterior aspect of the **left atrium**

Answer 36

Cross the anterior atrioventricular groove and open up diretcly into the **anterior surface** of the **rigth atrium** Up to three or four in number

Answer 37

Small veins that drain directly into teh cardiac cavity

Answer 38

**Vagus nerve:** parasympathetic supply that reduces heart rate **Cervical and T1 - T5 vertebrae:** sympathetic supply via the **superficial and deep cardiac plexus** which increases heart rate **Referred pain:** to neck / arm via the **T****1 - T5 afferent sympathetic nerves**

Answer 39

1. **Truncus arteriosus *(cephalic)*** 2. **Bulbus cordis** 3. **Ventricle** 4. **Atrium** 5. **Sinus venosus *(caudal)***

Answer 40

* 5 dilatations along primitive heart tube forms into adult heart structures * Dextral looping of the primitive heart aligns the heart chambers and structures * Septum and valves develop which allow for separation of the venous and arterial circulatory pathways **5 dilitations** cephalic 1. Truncus arteriosus 2. Bulbus cordis 3. Ventricle 4. Atrium 5. Sinus venosus caudal

Answer 41

1. The primitive heart tube elongates 2. Kinks 3. Caudal end **recieiving blood** from the sinus venosus comes to lie behind the cephalic end 4. **Sinus venosus** absorbs into the **atrium** 5. **Bulbus cordis** absorbs into the **ventricles** 6. Result of which is the atria and great veins lie behind the ventricles

Answer 42

Septum primum: grows **downwards** from the posterior and superior walls of the primitive common atrium - hole appears in upper part prior to fusion at lower border Septum secundum: second membrane **to the right** of the septum primum BUT remains incomplete - free lower edge

Answer 43

* Grows **downwards** from the posterior and superior walls of the primitive common atrium * Fuses with the endocardial cushions * Prior to complete fusion, a hole appears in the **upper** part of the septum = **foramen secundum (in the septum primum)**

Answer 44

= hole in the **upper part** of the **septum primum**

Answer 45

* Second memrbane to the **right** of the septum primum * Grows downwards * Incomplete growth and has **free lower border** * Hence does not fuse with endocardial cushions * Overlaps **foramen secundum** forming a valve-like structure that allowes blood to enter from the **rigth atrium to the left atrium = FORMAN OVALE**

Answer 46

## Footnote **Foramen secundum**

Answer 47

=Foramen ovale Allows bloods from the rigth atrium to enter the left atrium

Answer 48

10% have anatomically patent (but functionally closed) foramen ovale

Answer 49

1. Up-growth of septum from apex of the heart 2. Stops short if the endocardial cushiosn creating **interventricular foramen** 3. Single **truncus arteriosus** divides into the aorta and pulmonary trunk by the **SPIRAL SEPTUM** 4. **Spiral septum** continues growing down into the ventricles 5. Completes the division of the ventricles by forming the ***pars membranacea septi*** = small upper part of interventricular septum

Answer 50

**1. Primitive sinus venosus** fuses with Atrium: smooth walled part of the atrium in developed heart is the contributon from the sinus venosus , pectinate part is from the primitive atrium and forms the auricular appendage **2. Pulmonary venous trunk** is absorbed into the left atrium: the **pulmonary venous trunk** forms the **smooth**-walled part of the developed **left atrium**, trabeculated part if from the primitive **atria** and forms the **auricular appendage**

Answer 51

= continuation of the **sprial septum** forming the upper part of the interventicular septum, the spiral septum progresses down it divides the single **truncus arteriosus** into the **aorta** and the **pulmonary trunk** **Completes interventricular spetum to form left and rigth ventricles**

Answer 52

= SIX PAIRS

Answer 53

Six aortic arches (pairs) arise from the **truncus arteriosus**

Answer 54

**1st pair** **2nd pair** **5th pair** 3 pairs dissapear, 1st, 2nd and 5th

Answer 55

4th Aortic Arches **RIGHT:** Brachiocephalic and subclavian arteries **LEFT:** Arch of the aorta **HENCE:** **Distal sixth arch on the rigth dissapears, next arch is the 4th** **Distal sixth arch perisst as the ductus arteriosus on left** **Recurrent laryngeal nerve** is caught on the 4th arch on the rigth which is the **subclavian artery,** Caught on the sixth arch on the left with ends up being the **ligamentum arterosum**

Answer 56

3rd Aortic Arches **RIGHT and LEFT:** become carotid arteries

Answer 57

6th Aortic Arches **RIGHT:** proximal part forms the **right pulmonary artery** **LEFT:** proximal part forms the **left pulmonary arter**y and the distal part forms **ductus arteriosis**

Answer 58

1. Vagus nerve lies lateral to the **primitive pharynx** and is separated from it by the **aortic arches** 2. The vagus nerve passes medially caudal to the aortic araches to supply the developing **larynx** 3. Elongation occurs, the developing heart and aoritc arches elongate caudually catching the vagus nerve 4. **Right DISTAL** 6th aortic arch dissapears, **right** recurrent laryngeal next caught on the 4th aortic arch which is the **rigth subclavian artery** 5. **Left DISTAL** 6th aortic arch becomes the **ductus arteriosus** and hence the left recurrent laryngeal nerve is wrapped around the **ligamentum arteriosum**

Answer 59

## Footnote **T2**

Answer 60

## Footnote **T2/T3**

Answer 61

= Angle of Louis = maunbrosternal junction = second costal cartilage **= T4/ T5**

Answer 62

Inferior border of the scapula as it **overlies the 7th ribs is at the level of T8**

Answer 63

## Footnote **=T9**

Answer 64

**Lower part of the costal margin at the 10th rib** = subcostal line Passes through **L3**

Answer 65

**Manibrium is latin for handle** **Overlies aortic arch and corrosponds to T3-T4 vertebra** Manubrium is joined ot the body of the sternuma at the angle of luis

Answer 66

**= second costal cartilage** **= T4 / T5**

Answer 67

Superior angle of the scapula **= T2** Upper border of the manubrium / suprasternal notch **= T2/T3** Sternal angle **= T4/T5** Inferior border of the scapula as it overlies 7th rib **= T8** Xiphisternal joint **= T9** Subcostal line (at costal margin of 10th rib) **= L3**

Answer 68

**=C7** **C7 is the only cevrical vertebrae to have a significant spinous process** (the C1- C6 vertebrae have bifid spinous processes)

Answer 69

=Most inferior and lateral palpable heart beat **Normally: 5th intercostal space 9cm from the midline (midclavicular line)**

Answer 70

4th intercostal space

Answer 71

* Trachea commences at the **cricoid cartilage** at **C6** * Runs vertically downards and ends at the **level of the sternal angle at T5 just to the rigth of the midline** * In the erect position in full inspiration the trachea bifurcates at the level of **T6**

Answer 72

Rises higher than expected and can be injured causing pneumothorax (a classic case of this is during insertion of subclavian central line and subsequent respiratory decline) **Defined by a curved line drawn from the sternoclavicular joint to the junction between the medial third and middle third of the clavicle** Rising 2.5cm above the clavicle in a dome-shape

Answer 73

1. Highest point is the reaching from the ste**rnoclavicular joint to the junction of the first thrid and middle third of the clavicle** 2. Passes to the midline at the **Angle of Louis** 3. Descends to the **6th costal cartilage** 4. Then begins to pass medially 5. Crosses the **8th rib i**n the mid-clavicular line 6. Crosses **10th rib** at mid-axillary line 7. Crosses **12th rib** at the lateral border of the erector spinae muscle 8. At medial extremity it extends to just below the 12th rib margin **On the left side it runs away from midline to lateral sternal border at 4th costal cartilage**

Answer 74

You can accidentally open the pleura with a loin incision (daining subphrenic abscess or exposing kidney) As the upper incison curves eitehr towards the 10th rib at the costal margin or if it extends posteriorly to infring upon the pleura as it crosses the 11th / 12th rib

Answer 75

**Apex of both lungs follows the contours of the pleura** -sternoclavicular joint to junction of first thrid and middle third of the clavicle **Right** lung follows contour of mediastinal pleura **Left** lung has distinct cardiac notch and passes behind the 5th and 6th costal cartilages **Lower borders, crosses:** **6th rib mid-clavicular line** **8th rib mid-axillary line** **10th rib adjacent to vertebral column** _i.e. two rib spaces above the pleura_

Answer 76

Runs from 2.5cm lateral to the spine of **T3** Along the **5th intercostal space** Runs to to the **6th costal cartilage 3cm from the midline** **There is an oblique fissure on each side**

Answer 77

Continues as a horizontal line along the **4th costal cartilage (anteriorly heading backwards)** Meets oblique fissure as it cross the **5th rib** **Only present in the RIGHT lung**

Answer 78

**RIGHT SIDE:** **3rd** costal cartilage 1/2 inch form the sternum **6th** costal cartilage 1/2inch from the sternum **LEFT SIDE:** **2nd** COSTAL CARTILAGE **1/2 inch** from **sternum** **5th** *intercostal* *space* **3.5 inch** from the **MIDLINE**

Answer 79

* The i**nternal throacic arteries (internal mammary arteries)** run _vertically_ **behind the costal cartillages ~ 1.25cm lateral from the sternum** * They should be avoided in aspiration procedures of the lung as they can bleed dramatically

Answer 80

**_12 pairs_** **7** pairs that articulate with the sternum directly **ribs 1 - 7** **3** pairs that articular with the sternum via the costal cartilage above **ribs 8 - 10** **2** pairs of floatig ribs **ribs 11 -12**

Answer 81

Attaches to the stout neck of the rib Lateral costotransverse liagment - at level of vertebrae Superior costotransverse ligament - from vetrebrae above

Answer 82

Two facets **Superior facet: j**oins with the LOWER demifacet of the vertebrae BELOW **Inferior facet**: joins with the UPPER demifacet of the vertebrae BELOW

Answer 83

smooth facet for articulation with the **transverse prcoess** of the named vertebrae at that level

Answer 84

## Footnote **= angle of the rib**

Answer 85

* Flattended (from above --\> downards) * Prominent tubercle on inner border for attachment of anterior scalene muscle * Groove for suubclavian artery * Groove for subclavian vein * Single articular facet * Shortest

Answer 86

Subclavian artery and **lowest trunk of brachial plexus** lie behing anterior scalene muscle Site of anesthetic infiltration for the brachial plexus into the subclavian groove Most of the surface of clavicle is **occupied by a groove**, which gives **attachment to the Subclavius; the coracoclavicular fascia**, which splits to enclose the muscle, is attached to the margins of the groove.

Answer 87

**_1st, 10th, 11th and 12th_** **Rib 1** is shorter and wider than the other ribs. It only has one facet on its head for articulation with its corresponding vertebrae (there isn’t a thoracic vertebrae above it). The superior surface is marked by two grooves, which make way for the subclavian vessels. **Rib 2** is thinner and longer than rib 1, and has two articular facets on the head as normal. It has a roughened area on its upper surface, from which the serratus anterior muscle originates. **Rib 10** only has one facet – for articulation with its numerically corresponding vertebrae. **Ribs 11 and 12** have no neck, and only contain one facet, which is for articulation with their corresponding vertebrae RIb 11: shallow sibcostal groove, slight angle Rib 12: no groove, no angle

Answer 88

Criush injuries often cause fractures close to the **angle of the rib** as this the ribs weakest point during AP compression

Answer 89

**Roesler's sign =** enlarged collateral vessel Seen in: * **co-arctation of the aorta** * interrupted aortic arch * subclavian artery obstruction * AVM * Tetrallogy of fallot

Answer 90

Co-arctation means that the aorta beneath the narrowing would not recieve blood The internal throacic artery (internal mammary) branches prior to the co-arctation and passes vertically behind the costal cartillages Anterior intercostal branches of the internal throacic artery are connected to the intercostal arteries These **intercostal arteries** are a direct branch of the **descending aorta** Increased flow from the **internal throacic** --\> **anterior intercostal branches** --\> **intercostals** --\> **descending aorta** Increased blood flow down **inferior epigastric artery** too Produces Roesler's sign (Notching of the ribs)

Answer 91

* 0.5% of the population * 50% of cases are bilateral * Attachment ot the transverse process of **C7** * Articulate with the first rib * Some are truncated and have fibrous band connetcign to the first rib * Cause pressure on lowest trunk of the brachial plexus --\> **paraesthesia ober ulnar border of forearm and wasting of hand muscle (T1)** * **Can also cause post-stenotic dilatation of subclavian artery**

Answer 92

* Elastic costal cartlages means that fractures of the sternum are rare * Associated with **fracture-dislocations of the thoracic spine**

Answer 93

**Procedure:** length of artificial tubing, 3 to 4 millimeters in diameter, is sewn between either the su**bclavian or the carotid artery** and the corresponding side branch of the **pulmonary artery** **Indication:** Increase blood flow in pulmonary artery in cyanotic heart defects such as tetrallogy of fallot or pulmonary atresia

Answer 94

External intercostals run **forwards and downards** From rib above --\> to rib below Run from vertebare to costochondral junctionalm at the costsochondral junction teh muscle is replaced by the **anterior intercostal memrbane**

Answer 95

Run **backwards and downwards** Becomes the **posterior intercotsal membrane**

Answer 96

**External intercostal aponeurosis** = anterior intercostal membrane at point of costochrondral joint **Internal intercostal aponeurosis** = posterior intercostal membrane

Answer 97

Continuous with the internal intercostals Spans multiple intercostals at a time Anteriorly is more distinct as the **transversus thoracis muscle**

Answer 98

**1st and 2nd:** branches of **superior intercostal artery**, which is a branch of the **costocervical trunk**, which is the only branch of the second part of the subclavian artery **3rd - 12th**: direct branches of the descending aorta Each posterior intercostal artery branches to skin, muscle AND **spinal cord**

Answer 99

## Footnote **1st - 6th:** Direct branches of **internal throacic artery** These anterior intercostal arteries give rise to the perforatingbranches for spaces 1 -6 **7th - 9th:** Branches of the **musculophrenic artery** which a is branch of the internal thoracic artery **The bottom two spaces only have posterior intercostal arteries**

Answer 100

**Anterio rami of the thoracic nerves** **Each gives off :** 1. muscular branch 2. lateral cutaneous branch 3. anterior cutaneous branch

Answer 101

Local anaesthetic is infiltrated around the intercostal nerve trunk -arises from anterior primary rami of each thoracic nerve Needle injected on posterior back around angle of rib

Answer 102

Incision along the line of the **5th or 6th rib**

Answer 103

Lateral cutaneous branches (rami cutanei laterales) are derived from the intercostal nerves, about midway between the vertebræ and sternum; they pierce the Intercostales externi and Serratus anterior, and divide into anterior and posterior branches. The anterior branches run forward to the side and the forepart of the chest and skin, fourth nerve anterior branches supplying the areola and the mamma; those of the fifth and sixth nerves supply the upper digitations of the Obliquus externus abdominis. The posterior branches run backward, and supply the skin over the scapula and Latissimus dorsi.

Answer 104

Intercostal nerves 1 -2: supply fibers to the upper limb in addition to their thoracic branches Intercostal nerves 3 - 6 : limited in their distribution to the walls of the thorax Intercostal nerves 7- 11 : supply the walls of the thorax and abdomen. 7th intercostal nerve terminates at the xyphoid process, at the lower end of the sternum. 10th intercostal nerve terminates at the navel. 12th (subcostal) thoracic is distributed to the abdominal wall and groin.

Answer 105

Diaphragm is a dome-shaped septum that separates the thoracic and abdominal cavities and plays a role in respiration. It is made up of two portions: a peripheral muscular portion and a central tendinous aponeurosis It has three main openings for the IVC, oesophagus and aorta

Answer 106

1. Vertebral part: right and left crura, medial arcuate ligament, lateral arcuate ligamet and median arcuate ligament 2. Costal part: attached to inner aspect of lower six ribs and costal cartilages 3. Sternal portion: small muscular slips from deep surfae of xiphisterum

Answer 107

Arcuate ligament refers to the fibrous arches formed by the thickening of the fascia. The medial arcuate ligament is a thickening of the fascia of the psoas major muscle.

Answer 108

## Footnote Arcuate ligament refers to the fibrous arches formed by the thickening of the fascia. The lateral arcuate ligament is a thickening of the fascia of the quadratus lumborum muscle, which makes sense as this is lateral to the psoas major which makes up the medial arcuate ligament.

Answer 109

The median arcuate ligament is the fusion of the two medial borders of the left crus and right crus in front of the aorta Right crus: L1 - L3 Left crus: L1 - L2 Can cause compression of ceoliac artery, causing MALS

Answer 110

Phrenic nerve C3, C4, C5 Long course of phrenic nerve follows embryological course of diaphrgam

Answer 111

The sensory nerve fibres from the central part of the diaphragm also run in the phrenic nerve; hence, irritation of the diaphragmatic pleura (in pleurisy) or of the peritoneum on the undersurface of the diaphragm by subphrenic collections of pus or blood produces referred pain in the corresponding cutaneous area, the shoulder‐tip.

Answer 112

Peripheral part: intercostals Central tendon: phrenic nerve

Answer 113

**IVC: T8** - situated in central tendon, slightly right to midline - also site of transmission for right phrenic nerve **Oesophagus: T10** - situated in muscular fibres of left and rigth crura slightly to left of midline - transmits left gastric artery and vein - trasnmits two vagus nerves **Aorta: T12** - lies in midline - tansmits throacic duct and azygous vein Left phrenic nerve pierces diaphragm alone Greater and lesser splanchnic nerves pierce the crura Sympathetic chain passes behind the diaphragm deep to the medial arcuate ligament to reach the posterior abdominal wall

Answer 114

## Footnote **IVC: T8** - situated in central tendon, slightly right to midline - also site of transmission for right phrenic nerve

Answer 115

**Aorta: T12** - lies in midline - tansmits throacic duct and azygous vein

Answer 116

**Oesophagus: T10** - situated in muscular fibres of left and rigth crura slightly to left of midline - transmits left gastric artery and vein - trasnmits two vagus nerves

Answer 117

COME BACK TO

Answer 118

Cardia of stomach is above the hiatus. Hence reguritation of peptic juices is common. Leads to: - heart burn - oesophagitis - bleeding - stricture formation

Answer 119

Rolling hiatus hernia are also known as para-oesophageal hernia. The cardia remians beneath the diaphragm but the fundus rises above it. There is little regurgitation as the cardia is below the hiatus, cardio‐oesophageal junction is intact. Leads to: - epigastric discomfort - flatulence - dysphagia BUT no regurgitation because the cardiac mechanism is undisturbed.

Answer 120

Quiet inspiration is chiefly produced by the diaphragm. During active inspiration: - first rib is relatively stationary - ribs 2 - 6 increase anterior-posterior diameter of the thorax = pump handle - lower six ribs increase transverse diameter of the thorax = bucket-handle Diaphragmatic movement accounts for approximately 65% of air exchange whereas chest movement accounts for the remaining 35%.

Answer 121

Achieves increase in anterior- posteriro diameter of thoracic cavity Undertaken by ribs 2 - 6 (first rib relatively statsic)

Answer 122

Increases transverse diameter of thoracic cavity. Undertaken by lower six ribs.

Answer 123

Passive expiration is achieved by elastic recoil or lung parenchyma. Active expiration involves the muscles of the abdominal wall.

Answer 124

**Extrapleural fascia:** loose thin layer of connective tissue immediately below the visceral pleura -allows stripping of parietal pleura from thoracic cavity Unlike visceral pleura which is adhered to lung parenchyma

Answer 125

Double fold / reflection of the mediastinal parietal pleura below the lung root on each side Hence not a true ligament. -dead space that allows distension of the pulmonary veins

Answer 126

The parietal pleura is innervated by the intercostal nerves Hence inflammation of the pleura is referred along the same distribution, usually chest wall For the lower intercostals this can present as acute abdominal pain

Answer 127

**Anterior** 1. Isthmus of thyroid 2. Inferior thyroid vein 3. Sternohyoid muscle 4. Sternothyroid muscle **Lateral** 1. Common carotid artery 2. Lobes of thyroid **Posterior** 1. Recurrent laryngeal nerve 2. Oesophagus

Answer 128

**Anterior** 1. Commencement of brachiocephalic artery 2. Left common carotid artery 3. Lect brachicephalic vein 4. Thyrmus **Posterior** 1. Left recurrent laryngeal nerve 2. Oesophagus **Left** 1. Arch of aorta 2. Left common caortid artery 3. Left subclavian artery 4. Left recurrent laryngeal nerve 5. Pleura **Right** 1. Vagus nerve 2. Azygous vein 3. Pleura

Answer 129

PRE-TRACHEAL FASCIA

Answer 130

Trachealis = smooth muscle

Answer 131

15- 20 U-shaped open cartilage rings

Answer 132

**Commences C6 at inferior border of cricoid cartilage** **Extends to T4/T5 angle of Louis, bifurcates**

Answer 133

=tracheal tug The arch of the aorta passes over left main bronchus If there is aneurysmal dilatation, this will cause a downward movement of the trachea during systole

Answer 134

**Longitudinal incision:** vertical incision is made downwards from the cricoid cartilage, passing between the anterior jugular veins. - hook cricoid crtilage to pull trachea forward - incise pre-trachea fascia - retract isthmus of thyroid - circular incision in trachea **Transverse: i**ncision made half way between cricoid cartilage and sternal notch, better cosmesis Golden rule: stick exactly to the midline Neck is extended

Answer 135

Brachiocephalic vein can be above sternal notch, may encounter it Soft trachea, hard to identify, easy to dissect through posteriorly into oesophagus

Answer 136

The root of the lung is the collection of structures that connect the lung to the mediastinum.

Answer 137

The **root of the lung** is the collection of structures that connect the lung to the mediastinum. The **hilum** is the place on the lung where these structures enter and leave the lung.

Answer 138

**Right main bronchus** - more vertical - shorter ~ 1" - wider Passes directly to the root of the lung at T5 Upper lobe branch occurs prior to entering the hilum Passes **below** the pulmonaery atery to enter the hilum

Answer 139

**Azygous vein** lies posterior and arches over the top of the rigth main bronchus to enter to tyhe SVC anteriorly Pulmonary artery lies behind it to begin with and then passes in front of it

Answer 140

**Left main bronchus** - twice the length of the right ~ 2" - passes downards and outwards under the arch of the aorta and in front of oesophagus No branches prior to hilum Enters hilum at T6

Answer 141

## Footnote Superiorly: arch of aorta Pulmonary artery spirals from anterior in front to above superiorly Inferiorly: left pulmonary veins Anteriorly: left pulmonary veins Posteriorly: descending thoracic aorta and oesophagus

Answer 142

**During bronchoscopy, one can visualise:** - entire trachea - main and lobar bronchi - commencement of first segmental divisions

Answer 143

Widending of carina / angle of the bronchi during a bronchoscopy for maliugnancy is a poor prognostic marker Widening suggests involvement of the tracheobronchial lymph nodes around the bifurcation of the trachea

Answer 144

Right lung is shorter than the left as liver pushes up on diaphragm Right lung is more massive vs left due to the loss if mass from left sided heart indentation

Answer 145

**Resection** -each lobe has its own bronchus and blood supply so lobar resections are possible **Lobar pneumonia** -pneumococcus causes infection in single lobe **Lobar collapse** - blockage of the bronchus by tumours, mucus or foreign body leads to collapse of that lobe - air left in lung is re-absorbed and due to blockage the lobe cannot be ventilated

Answer 146

Upper lobe = anterosuperior Lower love = posteroinferior FRONT R: upper lobe down to 4th intercostal space, then middle lobe L: upper lobe throughout BACK R + L: upper lobe to 3rd intercostal and then lower lobe throughout

Answer 147

**Bronchial arteries** -direct branch from thoracic aorta Clinic point: during pulmonary embolism, lung parenchyma is perfused via the bronchial arteries and hence is not ischaemic, it means a full resolution is possible

Answer 148

Lung parenchyma is drained by the bronchial veins, these drain into the azygous vein The superior and inferior pulmonary veins carry oxygenated blood to the left atrium

Answer 149

Lymph drains centripetally from pleura --\> hilum **Bronchopulmonary** lymph nodes in the hilum --\> drain to **tracheobronchial** lymph nodes at the bifurcation --\> drian to **pretrachea**l lymph nodes --\> Mediastinal lymph nodes, **drain directly into bracheocephalic vein** **Right lung: All lobes drain to pulmonary and bronchopulmonary (hilar) nodes, and then to inferior tracheobronchial (carinal) nodes.** **Left lung:** **Superior lobe drains to pulmonary and bronchopulmonary (hilar) nodes and inferior tracheobronchial (carinal) nodes.** **Left inferior lobe drains also to pulmonary and bronchopulmonary (hilar) nodes and to inferior tracheobronchial (carinal) nodes, but then mostly to right superior tracheobronchial nodes, where it follows same route as lymph from right lung.**

Answer 150

**Pulmonary plexus at hilum** Sympathetic: T2 - T5/6 Parasympathetic: vagus nerve

Answer 151

Apex: adventitia of great vessels fused with apex of pericardium Base: fused with central tendon of diraphragm

Answer 152

**Anterior** 1. Sternum, attached by sternocardial ligaments 2. 3rd - 6th costal cartilages 3. Anterior margins of the lung **Posterior** 1. Oesophagus 2. Descending aorta 3. Vetrebra T5 - T8 **Lateral and Medial** 1. Lung roots 2. Mediastinal pleura 3. Phrenic nerves

Answer 153

**Oblique sinus** Bound by the IVC and four pulmonary veins, forms recess between atrium and pericardium, blind-ended cul de sac **Tarnsverse sinus** Bound behind by SVC and left arium and the pulmonary trunk / aorta in front, forms channel in which one can get around the pulmonary trunk and ascending aorta

Answer 154

Bound by the IVC and four pulmonary veins, forms recess between atrium and pericardium, blind-ended cul de sac

Answer 155

Bound behind by SVC and left arium and the pulmonary trunk / aorta in front, forms channel in which one can get around the pulmonary trunk and ascending aorta

Answer 156

Muscular ridge running between SVC and IVC (the two cavae) * Indicated on outer surface by a groove - the sulcus terminalis * Separates smooth-walled atrium derived from the **sinus venosus** from the rough-walled atrium extending into aurocular appendage derived from the **true fetal atrium**

Answer 157

Groove visible on external surface of the heart that marks the crista terminalis crista terminalis = muscular ridge running from SVC to IVC

Answer 158

Derived from the sinus venosus Seoparated from rough-walled atrium by crista terminalis

Answer 159

Derived from the true fetal atrium Extends into auricular appendage Separated from smooth portion by the crista terminalis

Answer 160

Trabeculations seen in the atrium, composed of pectinate muscle

Answer 161

## Footnote - Muscular ridge running between the inflow (atriovenitrcular) and outflow (pulmonary) tracts of the right venticle - Separates the two tracts to guide blood flow

Answer 162

Irregular muscular elevations around the inflow tract of the ventricle Some of which form papillary muscles

Answer 163

Muscular bands formed from trabeculae carneae in the ventricle that project into the lumen Connect to the valve leaflets through chordae tendinae Contraction during sytsole prevents valve prolapse of triscuspid and mitral valves

Answer 164

Muscular band in the right ventricle crossing teh ventricular cavity from the interventricular septum to the anterior wall of the ventricle Conveys right branch of the atriovntricular bundle

Answer 165

Smooth area just proximal to the pulmonary valve in the right ventricle Marks the outflow tract

Answer 166

=Bishop's Mitre Two valve leaflets Anterior leaflet bigger vs posterior leaflet Separates left atrium from left ventricle

Answer 167

Smooth-walled portion of the left ventricle just unddr aortic valve Marks the outflow tract The remainder of the left ventricle is rough-walled

Answer 168

Composed of three semilunar cusps **Labelled**: 1. Anterior 2. Left posterior 3. Right posterior Immediately above valvaes is dilated aortic sinus, turubulent blood flow around sinus helps to close aortic valve

Answer 169

Anterior sinus = Right coronary artery Left - posterior sinus = Left coronary artery Right - posterior sinus = nil

Answer 170

1. Sinostrial node - upper crista terminalis 2. Atrioventricular node - atrial septum adjacent to opening of coronary sinus 3. Atrioventricular bundle (of His) - interventicular septum, divides into left and right branch at junction between membranous and muscular septum

Answer 171

First part of conduction system =pace maker of the heart Situated in upper part of crista terminalis Just to the right of SVC From here, conduction spreads through atrial musuclature to atrioventricular node in atrial septum

Answer 172

Second node of the conduction system **Situated in the atrial septum adjacent to the opening of the coronary sinus** From sinoatrial node, impulses pass through atrial musculature to reach atrial septum

Answer 173

The atrioventricular branches (of His) occur at the junction of the membranous and muscular interventricular septum The atrioventricular node is situated in the atrial septum, from here it passes into the interventricular septum It branches at the junction The moderator band of teh rigth ventricle carries the rigth branch to the right anterior ventricular wall

Answer 174

1. **Great cardiac vein:** sits in anterior atrioventricular groove and passes around to coronary sinus 2. **Middle cardiac vein:** sits in inferior interventricular groove 3. **Small cardiac vein:** accompanies marginal artery at lower border of the right heart 4. **Oblique vein:** descends obliquely down from left atrium

Answer 175

**Coronary sinus: greatm middle, small and onblique cardiac veins** **Anterior cardiac veins** **Venae cordis minimi**

Answer 176

Three / four veins that cross atrioventricular groove and drain anteriro surface of the heart Empties directly into rigth atrium

Answer 177

1. Arises from ANTERIOR aortic sinus 2. Passes forward between pulmonary trunk and right atrium 3. Gives off sinoatrial branch at upper margin of atrium 4. Descends in the rigth part of the ATRIOVENTRICULAR GROOVE down to the inferior border 5. Gives off marginal branch 6. Passes around to inferior side where the atrioventricular groove meets interventricular groove 7. Anastomoses with left coronary artery here and gives off POSTERIOR INTERVENTRICULAR BRANCH 8. The posterior interventricular branch runs forward in the interventricular groove to the apex where it anastomose with anterior descending branch of left coronary artery

Answer 178

1. Arises from the LEFT-POSTERIOR aortic sinus 2. Passes behind and then to the left of the pulmonary trunk 3. Gives off anterior descending / anterior atrioventricular which supplies anterior aspect of both ventricles, runs down to the apex - has diagonal branch 4. Passes into atrioventricular groove and runs laterally to the left as teh left circumflex artery| - Left (obtuse) marginal branch 5. Left cirucmflex runs around to the posterior interventricular groove

Answer 179

1. Sinus venosus 2. Atrium 3. Ventricle 4. Bulbus cordis 5. Truncus arterisus From behind to foward

Answer 180

The single heart tube consists of: 1. sinus venosus 2. atrium 3. ventricle 4. bulbus cordis 5. truncus arteriosus Form behind forward As it enalrges, it kinks, with the caudal venous end passing behind the cephalic arterial end The sinus venosus absorbs into atrium The bulbus cordis absorbs into the ventricle

Answer 181

1. Septum primum grows downwards towards the endocardial cushions 2. Just prior to fusion with the endocardial cushions, a defect appears in the superior portion = FORAMEN SECUNDUM in the septum primum 3. A second septum, septum secundum growrs downwards to the RIGHT of septum primum covering the foramen secundum but not fusing with the endocardial cushions Forms valve-like **formamen ovale**

Answer 182

Remnants of the formane ovali post fusion

Answer 183

1. Fleshy up-growth from the apex of the heart 2. Septum fails to fuse with endocardial cushions and temporary interventricular foramen formed 3. Truncus arteriosis divides via a spiral septum into aorta and pulmonary trunk 4. This division progresses downt to meet ventricles meeting the interventricular septum 5. Contirbution of **pars membranacea septi**, completes ventricular division

Answer 184

6 pairs of aortic arches develop from the truncus arteriosus These arotic arches curve dorsally around the pharynx on either side joining to form two longitudinally placed aortae

Answer 185

Carotid arteries

Answer 186

Right: brachiocephalic artery and right subclavian artery Left: aortic arch and left subclavian artery

Answer 187

Reabsorbed

Answer 188

Right: Right pulonary artery Left: Left pulmonary artery AND ductus arteriosus

Answer 189

**1st and 2nd pairs reabsorbed** **3rd**: Carotids **4th** Right: Brachiocephalic artery and rigth subclavian artery Left: aortic arch and left subclavian artery **5th**: reabsorbed **6th** Right: Right pulmonary artery Left: Left pulmonary artery and ductus arteriosus

Answer 190

Vagus nerve lies lateral to primitive pharynx, separated from it by aortic arches Continuation of vagus nerve pass medially to supply developing larynx Process: 1. Elongation of neck 2. Caudal migration of the heart 3. Recurrent laryngeal nerves are caught and dragged downwards Right 4th and 6th distal aortic arches absorbed, hence on right side gets caught under 4th = right subclavian Caught on left by ductus arteriosus, looped around ligamentum arteriosum in adult

Answer 191

Atrial septal defect due to failure of the **septum secundum** to cover the **foramen secundum** (which is in the septum primum) The defect lies high up in the atrial wall and is relatively straight foward to correct surgically

Answer 192

Atrial septal defect due to **failure of the septum primum to fuse with the endocardial cushions** More problematic in comparison to the ostium primum as the **defect lies immediately above the atrioventricular bundle** **Can be associated with ventricular septal defect**

Answer 193

Ostium primum atrial septal defect and complete ventricular septal defect Leading to three cavity heart

Answer 194

Ostium secundum

Answer 195

Ostium primum

Answer 196

**Stenosis affecting any of the:** - trunk - valve - infundibulum of right ventricle If associated with with a ventricular septal defect then leads to cyanotic congenital heart disease Stenosis causes right ventricular hypertrophy, increase in right heart size allows shunting from right --\> left Causes deoxygenated blood to bypass lungs and enter aorta

Answer 197

## Footnote If associated with with a ventricular septal defect then leads to cyanotic congenital heart disease Stenosis causes right ventricular hypertrophy, increase in right heart size allows shunting from right --\> left Causes deoxygenated blood to bypass lungs and enter aorta

Answer 198

1. Pulmonary stenosis 2. Over-riding aorta 3. Ventricular septal defecrt 4. Right ventricular hypertrophy ## Footnote **Commonest cyanotic congenital heart disease**

Answer 199

**= failure of division of truncus arteriosus by spiral septum** Truncus arteriosus **divides unequally,** causing pulmonary stenosis and widended, over-arching aorta Due to unequal division, spiral septum fails to complete ventricular septum, normally provides pars membranacea septi --\> ventricular septal defect Pulmonary stenosis leads to right ventricular hypertrophy **Ventricular septal defect, right ventricular hypertrophy and over-riding aorta = RIGHT to LEFT shunt --\> CYANOSIS**

Answer 200

Relatively common defect Oxygenated blood passes from aorta into pulmonary trunk -aorta is at much greater pressure If left uncorrected: **--\> work hypertrophy of the left heart** **--\> pulmonary hypertension**

Answer 201

**Abnormality in the obliterative process of the ductus arteriosus** --\> leading to a significant narrowing in the aorta just distal to the rigth subclavian Often associated with other defects Collateral supply: 1. Arteries around the scapula anastomising with the intercostal arteries 2. Superior epigastric artery (internal thoracic branch) and the inferior epigastric artery (external iliac branch)

Answer 202

**Collateral supply:** 1. Arteries around the scapula anastomising with the intercostal arteries 2. Superior epigastric artery (internal thoracic branch) and the inferior epigastric artery (external iliac branch)

Answer 203

**Abnormal origin of right subclavian artery** **-proximal 4th aortic arch incorrectly absorbed** Right subclavian artery branches from dorsal aorta as the 4th branch **Passes behing the oesophagus and causes dysphagia**

Answer 204

**Incomplete division of truncus arteriosis** Leads to connection between aorta and pulmonary trunk Rare

Answer 205

1. T1 - T4 vertebral bodies 2. Great vessels 3. Trachea 4. Oesophagus 5. Thymus 6. Thoracic duct 7. Vagi 8. Left recurrent laryngeal nerve 9. Phrenic nerves

Answer 206

Bilobed Closely related to the left brachiocephalic vein, extends down into the **anterior inferior mediastinum** In the youn child, extends into the neck, sometimes as much as the inferior pole of the thyroid With age, infiltrated with fat, homogenous with surrounding fat except for its capsule

Answer 207

Commences at C6 at inferior border of cricoid cartilage Extends 25cm / 10" Finished at cardiac orifice at the cardia of the stomach

Answer 208

Commences in the midline at C6, as it descends towards thoracic inlet it passes to left of midline **Anterior**: Trachea Thyroid **Posterior** C6 - C7 vertebrae Prevertebral muscles covered in prevertebral fascia **Either side:** Common carotids Recurrent laryngeal nerves **Left side:** Subclavian artery Terminal part of the thoracic duct

Answer 209

Course * Passes from superior mediastium to posterior inferior mediastinum * Runs from left position back to midline at T5 * Then passes forwards and dowards coursing to the left (again) to oesophagial hiatus at T10 Anterior * Crossed by trachea * Left main bronchus (constricts it) * Pericardium (separating it from the left atrium) * Diaphragm Posterior * Thoracic vertebrae * Thoracic duct * Azygous vein + tributaries * Descending aorta Left * Left subclavian artery * Terminal part of the aortic arch * Left recurrent lsaryngeal nerve * Thoracic duct * Left pleura Right * Pleura * Azygous vein In posterior mediastinum the thoracic aorta lies to the left of the oesophagus, but as it descends the aorta passes behind and the oesophagus moves foeward to the hiatus

Answer 210

Short 3cm in length Passes through the oesophageal hiatus in right crus of the diaphragm of the diaphragm at T10 Lies in oesophageal groove on the posterior surface of the **left lobe of the liver** Oesophagus is covered by peritoneum on anterior and left surfaces Left crus of diaphragm lies behind the oesophagus

Answer 211

Not an anatomical sphincter **Mechanism composed of:** 1. Physiological high-pressure zone at terminal oesophagus (demonstrated on manometry) 2. Pinch-cock effect of the crural sling of the diaphragm 3. Positive intra-abdominal pressure acting on short-segment of abdominal oesophagus 4. Valve-like effect of the obliquity of the oesophagogastric angle 5. Plug-like effect of a rosette of mucosal folds at the cardiac orifice (seen on oesophagogastroscopy)

Answer 212

1. Outer layer of connective areolar tissue 2. Muscular layer of longitudinal muscle fibres 3. Muscular layer of circular muscle fibres 4. Submucous layer containing mucous glands (goblet cells) 5. Mucosa of stratified epithelium Upper 2/3rds are striated muscle Lower 1/3rd is smooth muscle

Answer 213

Inferior thyroid artery Branches of the descending thoracic aorta Left gastric artery

Answer 214

Cervical part: drains into inferior thyroid vein **Throacic part: azygous and partly left gastric veins** **=porto-caval anastomoses --\> oesophageal varices**

Answer 215

Normal oesophagus has three indentations: 1. Arch of aorta 2. Left main bronchus 3. Left atrium

Answer 216

**Peri-oesophageal lymph plexus** --\> **posterior mediastinal nodes** Both drain into the s**upraclavicular nodes** and into nodes around left gastric vessels It is not uncommon to be able to palpate hard, fixed supraclavicular nodes in patients with advanced oesophageal cancer.

Answer 217

Three important measuring points from the incisors for oesophagoscopy: **17cm /7**": commencement of the oesophagus **28cm /11":** crossed by left atrium **43cm /17":** termination of oesophagus Three points are narrowest parts of the oesophagus and the sites swallowed foreign bodies are most likely to become impacted and strictures are most likely to occur after swallowing corrosive fluids.

Answer 218

Dysphagia megalatriensis **=dilated left atrium** **Seen in mitral stenosis** Most serious complication is development of an atrio-oesophageal fistula resulting in fatal haematemesis

Answer 219

The oesophagus is crossely soley by the termination of the vena aygous on the **right side** Hence is side of approach for surgery

Answer 220

Oesophagus develops from primitive foregut Trachea and larynx also develop from floor of foregut **Development of tracheooesophageal ridges that meet in midline further progression of respiratory diverticulum --\> create a tracheooesophageal septum to differentiate trachea and oesophagus** **-separates from foregut** Hence, oesophageal atresia and tracheo-oesophageal fistula tend to occur together as it is due to a failure of the tracheooesophageal septum

Answer 221

Proximal oesophagus ends as blind end Distal oesophagus opens onto trachea at T4 to form fistula - billous vomiting immediately post feed - failre of NG tube, with loop of NG tube on CXR 95% of tracheo-oesophageal congenital anomalies

Answer 222

Throacic duct commences as **cisterna chyli** passes through aortic hiatus in diaphragm Cisterna chlyi lies between abdominal aorta and the right crus of the diaphragm

Answer 223

Commcnes at cisterna chyli as it passes through aortic hiatus 1. Ascends **posterior** to oesophagus 2. Inclines to the **left of oesophagus at T5** 3. Runs upwards **behind carotid sheath** 4. Descends **over left subclavian artery** to drain into **left brachiocephalic vein**

Answer 224

## Footnote **Thoracic duct drains left upper limb, head and neck and ENTIRITY below the diaphragm**

Answer 225

Rigth subclavian and jugular lymph trunksnormally join to form the **rigth lymphatic duct** The right **mediastinal** lymph trunk sometimes joins the **right lymphatic duct** so that all three join the **right brachiocephalic vein** at a common origin Rigth subclavian, jugular and mediastinal lymph can enter great veins of teh neck separately

Answer 226

***=microfilaria bancrofti*** =wuchereria bancrofti Human parasitic worm (filariworm) that causes lymphatic filariasis Filarial worms are spread by a variety of mosquito vector species -W. bancrofti is most common **Three phases** 1. Asymptomatic 2. Acute 3. Chronic - chylous ascites - chyluria -chylous pleural effusion.

Answer 227

1) **Throacic vertebral fractures**, lower duct in close apposition 2) **Mobilsing oesophagus** during oesophagectomy Tears in the thoracic duct leads to a **CHYLOTHROAX**

Answer 228

Thoracic duct can be damaged during block dissection of the neck **If noticed, it should be ligated.** -if missed causes a **chylous fistula in the neck** Lymph drains through anastomoses with the venous system

Answer 229

Sympathetic trunk lies just lateral to the mediastinum behind the parietal pleura Descending from the cervical chain, it crosses: 1. **Neck** of the first rib 2. **Head** of ribs 2 - 10 3. **Bodies** of 11th - 12 throacic vertebrae Hence passes from lateral to medial Then passes behind the **medial arcuate ligament** to continue as **lumbar sympathetic trunk**

Answer 230

**Gangion of first thoracic spinal nerve joins with that of the inferior cervical ganglion to form the stellate ganglion** -occassionally the second and third thoracic ganglion are involved Stellate ganglion is relatively big (10-12 x 8-20 mm) compared to much smaller thoracic, lumbar and sacral ganglia and it is polygonal in shape (L. stellatum = star-shaped). Also known as the cervicothoracic ganglion Relations of the apex of the stellate ganglion: - covered by the endothoracic fascia and parietal pleura - right stellate ganglion is in relation with right brachiocephalic vein anteriorly - right stellate ganglion is in relation with sternal part of subclavian artery anteriorly - laterally: first intercostal artery - medially: longus colli muscle

Answer 231

The stellate ganglia may be cut in order to decrease the symptoms exhibited by Raynaud's phenomenon and hyperhydrosis (extreme sweating) of the hands. Injection of local anesthetics near the stellate ganglion can sometimes mitigate the symptoms of sympathetically mediated pain such as complex regional pain syndrome type I (reflex sympathetic dystrophy), and PTSD. Injection is often given near the **Chassaignac's Tubercle (**anterior tubercle of transverse process of C6) due to this being an important landmark lateral to the cricoid cartilage. It is thought that anesthetic is spread along the paravertebral muscles to the stellate ganglion.

Answer 232

=MYELINATED, hence white Inflow bundle into paravertebral ganglia for sympathetic trunk =pre-ganglionic fibre passing into vetrebral ganglion

Answer 233

=**UNMYELINATED**, hence **GREY** **Outflow** bundle from paravertebral ganglia for sympathetic trunk =**POST**-ganglionic fibre passing out of vetrebral ganglion, joins back to spinal nerve to supply target organ

Answer 234

**=SPLANCHNIC NERVE** **Splanchnic nerve can either be in the form of:** 1. post ganglionic splanchnic nerve in which the pre-ganglionic neuron has synapsed in the para-vertebral ganglia 2. pre-ganglionic splanchnic nerve in which the nueron has not synpased in the paravertebral ganglion and has instead passed to a peripheral ganglia near the target organ

Answer 235

**Four possibilities** 1. Pre-ganglionic neuron synpases in paraveretbral ganglia at same level, the post ganglionic neuron joins the **spinal nerve at same level** 2. Pre-ganglionic neuron synpases in paraveretbral ganglia at same level, the post ganglionic neuron then **ascends or descends to join a spinal nerve at different leve**l **Neurons leave the sympathetic trunk not through a spinal nerve, i.e. as part of the splanchnic nerves** **3. post ganglionic splanchnic nerv**e in which the pre-ganglionic neuron has synapsed in the para-vertebral ganglia **4. pre-ganglionic splanchnic nerve** in which the nueron has not synpased in the paravertebral ganglion and has instead passed to a peripheral ganglia near the target organ

Answer 236

Sympathetic fibres are distributed with each of the thoracic spinal nerve to innervate the skin

Answer 237

**Post-ganglionic fibres from T1 - T5** supply the thoracic viscra -heart, great vessels, lungs, and oesophagus

Answer 238

Mainly pre-ganglionic fibres from **T5-T12** form the splanchnic nerves - then pierce crura of the diaphragm - **pass to the coeliac, superior mesenteric, inferior mesenteric, renal ganglia to synapse synapse** - post-ganglionic fibres then pass to target organ **Divisions** Greater splanchnic nerve **T5 - T10** Lesser splanchnic nerve **T10 - T11** Least splanchnic nerve **T12** Splanchnic nerves lie medial to sympathetic trunk on bodies of thoracic vertebrae **-seen through the parietal pleura**

Answer 239

Hypotension can result seconday to a loss of vasoconstrictor sympathetic outflow From T5 down, there are pre-ganglionic fibres passing to provide sympathetic vasoconstricting input to the abdominal viscera -paralysed by injection of anaesthetic