Thorax Flashcards

Question

Diaphragm: Neurovasculature

Answer 1

**Arterial supply:** * musculophrenic * Pericardiophrenic * intercostal arteries * Superior and inferior phrenic arteries **Venous drainage:** same named veins into the system venous system **Innervation:** Bilateral phrenic nerve C3,4,5 Intercostal nerves supply proprioceptive fibres **Lymphatics:** Coeliac nodes and perihilar nodes

Answer 2

Congenital diaphragmatic eventration

Answer 3

Pectoralis major is a large, fan-shaped muscle. **Origin:** sternum, superior six costal cartilages and medial half of the clavicle **Insertion:** lateral lip of the bicipital groove of the humerus **Arterial:** Perforators from the internal thoracic and the thoracoacromial arteries **Innervation:** medial and lateral pectoral nerves **Action:** flexion, adduction and internal rotation of the shoulder joint **Variant anatomy:** * Sternalis muscle * Poland syndrome

Answer 4

The aortic arch is a large arterial trunk that connects the ascending aorta the descending aorta **Function:** Carries and initial distribution of the majority of the body’s arteries blood supply

Answer 5

Pectoralis minor is a muscle of the anterior chest wall that inserts into the pectoral girdle. It lies deep to and is completely covered by pectoralis major. It divides the axillary artery into 3 parts. **Origin:** anterior ribs 3-5 near the costal cartilages **Insertion:** coracoid process of the scapula **Innervation:** medial and lateral pectoral nerves **Action:** depresses shoulder and elevation of ribs 3-5 **Arterial:** Perforators from the internal thoracic and the thoracoacromial arteries **Variant anatomy:** * pre-fixed origin: ribs 2-4 * post-fixed: ribs 4-6 * Poland's syndrome also

Answer 6

origin: superior nuchal line, inion, nuchal ligament and spinous processes of C7-T12 vertebrae insertion: clavicle and scapula innervation: accessory nerve (CN XI) action: complex movements of the scapula and neck Arterial: Thoracodorsal artery

Answer 7

origin: spinous processes of T7-T12 and thoracolumbar fascia; posterior third of the iliac crest; 9th-12th ribs, inferior angle of the scapula insertion: floor of the bicipital groove of the humerus innervation: thoracodorsal nerve arterial supply: thoracodorsal artery (a branch of the subscapular artery) action: adduction, internal rotation and extension of the shoulder joint

Answer 8

**Layers:** adventitia, media and intima **Origin:** T4 plane continuation of the ascending aorta **Course:** posterior and to the left in the superior mediastinum **Termination:** continuation as the descending aorta pass the level T4 **Branches:** brachiocephalic trunk, Left common carotid artery, left subclavian artery

Answer 9

**Superior:** Large vessels of the superior mediastinum **Inferior:** recurrent laryngeal (which one), ligament arteriosum, the bifurcation of the pulmonary trunk **Anterior:** thymus or thymic reminant, fat **Posterior:** trachea, oesophagus, thoric duct crosses from right to left **Lateral:** right superior vena cava, terminination of the azygos, right upper lobe left: left upper lobe lung

Answer 10

* Double arch * Bovine arch common origin of the left common carotid and brachiocephalic trunk * Left common carotid from the brachiocephalic trunk **Branches directly from the aorta:** * Thyroid Ima * Vertebral artery (most commonly the left) * Right subclavian and right common carotid **Right sided arch:** * Type 1 - mirror * Type 2 – absent left subclavian * Type 3 – isolated left subclavian

Answer 11

The coronary arterial circulation is the system that supplies oxygenated blood the myocardium during diastole **Location:** wrapped around the surface of the heart, looks like and inverted crown, located beneath the visceral layer of serous peroicardium

Answer 12

**Origin:** Right coronary cusp **Course:** following the right atrioventricular groove around to the posterior aspect of the heart **Termination:** Continues as the posterior interventricular artery in right circulation dominant hearts

Answer 13

* Sinoatrial nodal artery * Conus artery * Sinotubular artery * Acute marginal branches * Posterior interventricular

Answer 14

* Obtuse marginal * Circumflex * LAD

Answer 15

Continues in the left atrioventricular groove around the posterior aspect of the heart gives of the posterior interventricular in left dominant hearts

Answer 16

Follows the anterior interventricular groove Terminates at the apex may anastomose with the posterior interventricular artery **Branches:** Obtuse marginal, septal perforators, diagonal branches

Answer 17

Malignant course: artery has aberrant course and passes between the aorta and pulmonary trunk Non-malignant course: aberrant from the above described course however does not pass between large pulsating vessels Origin from non-similarly named aortic cusp Right or left side dominance as described above

Answer 18

The coronary sinus drains in the right atrium its tributaries: * Great cardiac vein (follows circumflex and LAD) * Middle cardiac vein (Follows the posterior interventricular) * Small cardiac vein (follows RCA) Anterior cardiac veins drain directly into the right ventricle Smallest cardiac veins drain directly into all four ventricles

Answer 19

The internal thoracic artery (previously called the internal mammary artery) supplies the anterior body wall and its associated structures from the clavicles to the umbilicus.

Answer 20

**Origin:** First part of the subclavian arteries bilaterally **Course:** * Enters the thorax through the superior thoracic aperture posterior to the subclavian vein * Descends lateral to the lateral border of the sternum * Runs between the transversus thoracus muscle posteriorly and the costal cartilages and internal intercostal muscles anteriorly * At the sixth-to-seventh costal cartilages the internal thoracic artery bifurcates into two terminal branches - musculophrenic artery and superior epigastric artery.

Answer 21

* Superior and inferior anterior intercostal arteries within each intercostal space * Pericardiophrenic artery (runs with the phrenic nerve) * Perforating branches * musculophrenic artery (terminal branch) * superior epigastric artery (terminal branch)

Answer 22

* The internal thoracic artery supplies the anterior body wall from clavicle to umbilicus including the sternum and the breasts. * Via the pericardiophrenic artery it supplies the mediastinum, thymus, phrenic nerves and pericardium.

Answer 23

* anomalous origin in 20% * second part (uncommon; ~7%) and third part (rare; ~1%) of subclavian artery * terminal trifurcation (~12.5%) with an additional xiphoid branch

Answer 24

Subclavian artery is a large artery that supplies the arm, neck, anterior thorax, posterior circulation of the brain **Function:** Deliver oxygenated blood **Location:** Beneath the clavicles bilaterally

Answer 25

**Origin:** the third branch on the aortic arch (normal configuration) **Course:** Ascends through the superior thoracic aperture, posterior to the brachiocephalic veins, between the anterior and middle scalene muscles **Divided into 3 parts:** 1^st part from origin to the medial edge of scalenus anterior 2^nd part to the lateral edge of scalenus anterior 3^rd part to the lateral border of the first rib **Termination:** continues as the axillary artery

Answer 26

**1^st part:** * Vertebral * Internal thoracic * Thyrocervical trunk **2^nd part:** * Costocervical trunk * Dorsal scapular **3^rd part:** * None

Answer 27

* Origin variants * Aberrant right subclavian (between trachea and oesophagus) * Order of branches may vary * Origin of vertebral artery from the aorta

Answer 28

function as an alternate venous return pathway in the setting of IVC occlusion

Answer 29

Origin: Formed by the union of the right ascending lumbar veins and right subcostal veins at the level T12-L2 Course: Ascending in the retroperitoneal space of the abdomen, enters the chest through the aortic hiatus (however may pierce the crus), it continues to ascend in the posterior mediastinum Termination: Arches over the right main bronchus to drain in to the superior vena cava.

Answer 30

* Hemiazygos vein * Accessory hemiazygos vein * Right superior intercostal vein * Posterior right intercostal veins * Right superior phrenic vein * Tracheal veins * Oesophageal veins * Pericardial veins * Vertebral venous plexus

Answer 31

Origin: Formed by the union of the left ascending lumbar veins and left subcostal veins Course: Also through the aortic hiatus Termination: Crosses the midline at T8-T9 to drain in the azygos vein

Answer 32

* Left posterior intercostal veins * Left superior phrenic vein * Left renal vein (sometimes) * ICV sometimes * The left superior intrercostal vein drains directly into the SVC

Answer 33

* Azygos continuation of the svc * Azygos lobe and fissure * Hemiazygos continuation of the SVC

Answer 34

The lungs have dual arterial supply and venous drainage.

Answer 35

Transport deoxygenated blood to the lungs, Receive all of the arterial output of the right ventricle **Origin:** Pulmonary trunk bifurcation at the level of the transthoracic plane **Course:** Enters the hilum and divides into lobar, then segmental, then subsegmental arteries, then intralobular arteries, they follow the bronchi Termination: Capillary beds of the alveoli

Answer 36

Supply 1% of the blood to lung, only high-pressure oxygenated supply to the lungs There are usually two on the left: * Superior left bronchial artery (arises from the arch) * Inferior left bronchial artery (arises from the desending aorta) There is usually one on the right arising from a posterior intercostal artery (intercostalbronchial trunk)

Answer 37

drain oxygenated blood from the lungs to the left atrium. Typically 2 drain each lung: * Right superior – Right upper and middle lobes * Right inferior – Right lower lobe * Left superior – Left upper lobe * Left inferior – Left lower lobe * The pulmonary veins course in the intersegemental septa and do not course with the bronchi like the pulmonary arteries do.

Answer 38

* Bronchial veins – drain the bronchi and hilar structures and the middle portion of the oesophagus. * Divisible into deep and superficial bronchial veins: * Deep bronchial veins – Drain the deep structures of the lung into the left atrium or pulmonary veins * Superficial bronchial veins – drain the hilum and plura. On the right they drain into the azygos, on the left they drain into the accessory hemiazygos vein.

Answer 39

The superior vena cava (SVC) is a large valveless venous channel formed by the union of the brachiocephalic veins. It receives blood from the upper half of the body (except the heart) and returns it to the right atrium.

Answer 40

Origin: Lower border of the first right costal cartilage Course: Descends vertically behind the second and third intercostal spaces to drain into the right atrium at the level of the third costal cartilage. Its lower half is covered by the fibrous pericardium, which it pierces at the level of the second costal cartilage.

Answer 41

* azygos vein * small veins draining the pericardium and other mediastinal structures

Answer 42

* left lateral: aortic arch, trachea * right lateral: pleura, right upper lobe, right phrenic nerve * anteriorly: thymus, manubrium * posteriorly: azygos vein * superiorly: brachiocephalic veins, superior thoracic aperture * inferiorly: pericardium, right atrium

Answer 43

brachiocephalic veins: drain into the right atrium separately SVC duplication left sided SVC

Answer 44

The venous drainage of the thorax is the vascular system that returns deoxygenated blood from the thorax to the heart

Answer 45

Couse inferior aspect of each rib Drains: internal thoracic and musculophrenic veins

Answer 46

Origin: intercostal spaces Course: Inferior to the posterior aspect of each rib (4 to 11) Termination: drain into azygos system

Answer 47

Origin: 1^st intercostal space Termination: drains into the brachiocephalic veins

Answer 48

Origin 2^nd and 3^rd intercostal veins join to form the superior intercostal vein Termination: drains into the ayzogos and brachiocephalic (right and left)

Answer 49

Superior intercostal may also drain the 4^th intercostal space Posterior intercostal veins may be drained by different elements of the azygos system

Answer 50

The phrenic nerves are mixed sensory/motor nerves that course through the neck and thorax to innervate the diaphragm

Answer 51

**Origin:** ventral rami of C3, C4 and C5 **Course:** Passes on the anterior surface of scalenus anterior, over the dome of the apical pleura, entering the superior thoracic aperture posterior to the subclavian veins **Left:** Descends lateral to the left subclavian artery, passes anterior to the hilum, pierces the diaphragm directly to enter the abdominal cavity. **Right:** Descends with the superior and inferior vena cava. Enters the abdomen with the inferior vena cava through the caval hiatus at level T8 Within the abdomen the both divide in the anterior, lateral and posterior branches. Coursing out in a radial pattern. **Supply:** Sole motor supply to each hemidiaphragm, sensation to the central tendon * Diaphragm * Mediastinal pleura * Pericardium * Central diaphragmatic pleura

Answer 52

* Course anterior to subclavian vein * May pierce the anterior scalene muscle * Accessory phrenic nerve * Contribution from C2 or C6 * May supply branch to subclavius

Answer 53

The thoracic duct is the main lymphatic channel for the return of chyle to the venous system.

Answer 54

* Origin: continuation from the cistern chyli * Course in the retroperitneum posterior to the great vessels ascending, entering the thoracic cavity via the aortic hiatus at T12, continues to ascend in the posterior mediastinum on the right hand side initially, swapping sides at the level T4, continuing superiorly through the thoracic inlet, anterior to the subclavian artery, anterior to the anterior scalene, draining in the convergence of the left subclavian and internal jugular.

Answer 55

* Anterior: oesophagus, left atrium, carina * Posterior: vertebral column, symphathetic chain of ganglion * Left lateral: descending aorta, left lung and pleura * Right lateral: azygos vein, right lung and pleura

Answer 56

* Variant anatomy in 40% of the population * Duplication * Aberrant termination * Multiple terminal channels Continues on the right to terminate in the right internal jugular vein

Answer 57

Bilateral prominences of the anterior thorax **Function:** Lactation

Answer 58

* Mixed fatty and glandular tissue comprise the bulk of the breast * Structural support via fibrous tissue known as the ligaments of Cooper * Typically divided into 5 sections, four quadrants centered on the nipple and an axillary tail * Glandular tissue is comprised of lobules draining into lactiferous ducts converging on the areola to drain to the nipple * Lactiferous lobules are modified apocrine glands, typically 14-18, draining to the nipple areola complex

Answer 59

**Arterial supply:** * Performing branches from the internal thorax and intercostal arteries * Thoracoacromial artery * Lateral thoracic arteries **Venous drainage:** * Axillary vein * Internal thoracic vein * Posterior intercostal veins **Innervation:** Thoracic intercostal nerve T3-T5 Supraclavicular nerves **Lymphatic drainage:** Initially into Sappy’s plexus (subareolar plexus) then into one of three routes (AIR): * Axillary pathway – runs from the inferior edge of the pec major to the pectoral group of axillary nodes * Internal mammary pathway – passes through pec major, connect may cross the medial plane to the contralateral breast * Retromammary pathway – from the posterior portion of the breast 75% of lymph from the breast is drained via the axillary nodes

Answer 60

* Hypoplasia * Amastia * Amazia * Polythelia * Polymastia

Answer 61

The lymphatic drainage of the breast originates from the breast lobules and flows into a subareolar plexus, called Sappy’s plexus. From this plexus, lymphatic drainage takes place through three main routes:

Answer 62

**Axiallary or lateral pathway:** Receives 75% of the lymph this pathway runs around the inferior edge of the pectoralis major and reaches the pectoral group of axillary nodes. **Internal mammary pathway:** Originates from both the medial and lateral halves of the breast and passes through the pec. Major. Connections may lead across the median plane and hence to the contralateral breast **Retromammary pathway:** Drains the posterior portion of the breast

Answer 63

Lymphatics may reach the sheath of the rectus abdominus and the sub peritoneal and subhepatic plexuses.

Answer 64

The left ventricle is one of four heart chambers. It receives oxygenated blood from the left atrium and pumps it into the systemic circulation via the aorta.

Answer 65

* The left ventricle is conical in shape * anteroinferiorly projecting apex * longer with thicker walls than the right ventricle * separated from the right ventricle by the interventricular septum, * Internally, there are smooth inflow and outflow tracts and the remainder of the left ventricle (mainly apical) is lined by fine trabeculae carnae.

Answer 66

**Arterial supply:** * left anterior descending artery: supplies the free wall and most of the papillary muscles * left circumflex artery: supplies the free wall **Venous drainage:** * great cardiac vein, middle cardiac vein and posterior vein of the left ventricle: drain into the coronary sinus * tiny myocardial thebesian veins drain directly into the right ventricle **Innervation:** * Superior and inferior cardiac plexi * Conduction system of the heart **Lymphatics:** Lymphatics system of the heart draining into the tracheobronchial, para-aortic nodes and superior phrenic nodes.

Answer 67

double-inlet ventricle: inflow from both the right and left atria parachute valve: mitral valve chordae tendineae inserting into a single papillary muscle

Answer 68

The right atrium (RA) is one of the four chambers of the human heart. **Function:** the first chamber to receive deoxygenated blood returning from the body, pre-loads the right ventricle with increase it efficiency (Frank Starling law)

Answer 69

The right atrium receives deoxygenated blood from the superior vena cava (SVC), the inferior vena cava (IVC), the coronary sinus (covered by the thebesian valve), and the thebesian veins. Grossly ellipsoid in shape except for the atrial appendage. The right atrium is separated from the left atrium by the interatrial septum. Which has an indentiation in it called the fossa ovalis (was previously the foramen ovalis prior to birth) The right atrium leads into the right ventricle through the tricuspid valve. The crista terminalis is a muscular ridge on the anterior aspect of the chamber. The atrium is lined by pectinate muscles to the left of this crest, and these extend into the right atrial appendage.

Answer 70

**Blood supply:** arterial supply is primarily from the right coronary artery (RCA) and several of it's branches: conus artery (first branch off RCA in 55%, otherwise arises off left circumflex artery) sinoatrial node artery (usually second branch off RCA in 60%) acute marginal branches **Venous drainage:** variable veins drain the atrial wall tiny myocardial thebesian veins drain directly into the right ventricle **Nerve supply:** The right atrium is the location of the sinoatrial node, the heart's pacemaker. It is located subepicardially in the terminal groove, near the junction of the SVC and right atrium. Although the sinoatrial node can generate conduction rhythms spontaneously, it is regulated by the vagus nerve (CN X) and the cardiac sympathetic plexus.

Answer 71

Eustachian valve of the IVC

Answer 72

The oesophagus is a muscular tube that connect the pharynx to the stomach **Function:** convey food bolus to the stomach

Answer 73

~23-37cm in length Divided into segments: * Cervical – hypopharynx to superior thoracic aperture * Thoracic – Sup. Thoracic aperture to the oesophageal hiatus * Intraabdominal – diaphragm to cardia of the stomach **Course:** through the superior thoracic inlet, running in the posterior mediastinum behind the trachea, passes through the diaphragm through the oesophageal hiatus at level T10 **Termination:** joins the cardia via the lower oesophageal sphincter

Answer 74

Anterior: trachea, carina, heart Posterior: vertebral bodies from C4 to T11 Lateral: Ascending laryngeal nerve in the tracheooesophageal groove

Answer 75

**Arterial supply:** * Inferior thyroid * Direct branches of the desending aorta * Braches from the left gastric **Venous drainage:** * Superior: Inferior thyroid plexus * Middle: Azygos system * Inferior: via the left gastric to portal vein **Innervation:** Oesophageal plexus supplied by the vagus and sympathetic chain of ganglions **Lymphatics**: * Deep cervical * Posterior mediastinal * Coeliac

Answer 76

* Oesophageal bronchus * Oesophageal atresia * Tracheo-oesophageal fistula * Duplication cyst * Fenestrated oesophagus

Answer 77

Anterior: trachea, cricoid cartilage, the isthmus of the thyroid Posterior: bodies and disc of vertebra C4 – C7 Lateral: Trachea oesophageal grooves, right and left recurrent laryngeal nerves, the carotid spaces Superior: Cricopharygeus, oropharynx Inferior: Thoracic oesophagus

Answer 78

Anterior: Trachea, left recurrent laryngeal nerve, pericardium Posterior: Thoracic vertebral bodies, thoracic duct, azygos veins, descending aorta Lateral: Right – Pleura, terminal part of the azygos vein, Left – Left subclavian artery, aortic arch, thoracic duct, pleura Superior: Cervical oesophagus Inferior: Diaphragm, oesophageal hiatus, the abdominal component of the oesophagus

Answer 79

Anterior: Left vagus nerve, posterior surface of the heart Posterior: Right vagus nerve, left crus of the diaphragm Lateral: Left – fundus of the stomach, spleen, Right - coeliac axis Superior: Thoracic oesophagus Inferior: Cardia of the heart

Answer 80

The pericardium is a sac like covering of the heart and the root of the great vessels **Function:** Reduce friction between the heart and surrounding tissue to allow for cardiac movement

Answer 81

Fibrous outer sac is referred to as the fibrous pericardium, it is fused to: * central tendon of the diaphragm * sternum via the superior and inferior sternopericardial ligaments * roots of the great vessels * pre-tracheal fascia The serous inner sac is divided into 2 layers between which there is 15-50mls of pericardial fluid. The outer layer of parietal serous pericardium is fused to the fibrous pericardium, the inner layer is adherent to the surface of the heart and origins of the great vessels

Answer 82

**Sinuses:** * Oblique sinus – formed behind the left atrium bounded by the origins of the superior and inferior vena cava and the pulmonary veins * Transverse sinus – between the aorta and pulmonary trunk and the atria posteriorly **Recesses:** * Pulmonic venous recess right and left * Pulmonary recess right and left * Superior and inferior aortic recess * Postcaval recess

Answer 83

**Arterial supply:** Pericardiophrenic and musculophrenic arteries branches of the internal thoracic **Venous drainage:** Pericardiophrenic and musculophrenic veins into brachiocephalic and internal thoracic veins **Innervation:** * Superior and inferior cardiac plexus supplied by the vagus and the sympathetic chain of ganglion * Phrenic nerves

Answer 84

* Inferior: central tendon of the diaphragm * Anterior: Sternum and costal cartilages (3-7), lung and plura (thymus in children) * Lateral: pleural and lung, phrenic nerves, * Medial: heart and origin of the great vessels

Answer 85

* Agenesis of the pericardium * Pericardial cysts

Answer 86

The pleura are serous membrane sacs that contain the lungs **Function:** reduce friction between the lungs and the thoracic walls

Answer 87

Divided into the parietal and visceral pleural with 15-50ml of pleural fluid between them The visceral pleura invaginates the fissures of the lungs The parietal pleura is named after the surface it covers: * Cervical * Costal * Diaphragmatic * Mediastinal

Answer 88

* 2^nd rib – both descend midline * 4^th rib – the left deviates for the heart * 6^th rib – the right and left deviate for the heart * 8^th rib – Right and left both pass the mid clavicular line * 10^th rib – right and left pass the midaxillary line * 12^th rib – right and left travel posteriorly around the chest wall

Answer 89

**Blood supply:** Visceral pleura: Bronchial and pulmonary arteries Parietal pleura: Internal thoracic, intercostal and phrenic **Venous drainage:** Bronchial and pulmonary veins **Lymphatics:** Perihilar nodes **Innervation:** The parietal pleural is innervated by the phrenic nerves and the intercostal nerves (mediastinal and costal parts respectively)

Answer 90

Anterior: Anterior thorax Posterior: posterior thorax and thoracic vertebra Lateral: rib intercostal muscles etc Inferior the diaphragm Superior the superior thoracic aperture

Answer 91

* Azygos lobe * Agenesis * Superior and inferior accessory fissures of the right lung * Left horizontal fissure

Answer 92

The segmental anatomy of the lung describes the division of the lung into segments based the the supply of segmental bronchi.

Answer 93

The trachea divides at the carina (T4) forming the right and left main stem bronchi. These further divide into lobar bronchi. Which then in turn divide into segmental bronchi. The lung supplied by each segmental bronchi is defined as a lung segment. In general each lung has 10 segments, giving 20 in total Each segment is an independent anatomically functional unit. This allows for discrete surgical resection.

Answer 94

**Upper lobe:** * Apical (B1) * Posterior (B2) * Anterior (B3) **Middle lobe:** * Lateral (B4) * Medial (B5) **Lower lobe:** * Superior (B6) * Medial (B7) * Anterior (B8) * Lateral (B9) * Posterior (B10)

Answer 95

**Upper lobe:** * Apicoposterior (B1/2) * Superior lingular (B4) * Inferior lingular (B5) * Anterior (B3) **Lower lobe:** * Anteriomedial (B7/B8) * Lateral (B9) * Posterior (B10) * Superior (B6)

Answer 96

* Azygos lobe * tracheal broncus * cardiac bronchus * oesophageal bronchus

Answer 97

The thymus is a T-cell producing lymphoid organ in the anterior mediastinum that plays a role in the development of the immune system, particular the maturation of T-cells. It typically has a retrosternal location and hence can mimic retrosternal pathology.

Answer 98

It is relatively large in infancy Grows considerably immediately after birth maximal weight in adolescence between 12 and 19 years then gradually involuting with age with progressive fatty replacement of the cellular components. Consist of two lateral lobes touching in the midline, situated partly in the thorax, partly in the neck. The gland extends from as high as the lower border of the thyroid gland to the fourth costal cartilage downwards.

Answer 99

Anteriorly: sternum, origins of the inferior strap muscles Posteriorly: pericardium, aortic arch, great vessels, left brachiocephalic vein, trachea Laterally: pleura, pretracheal fascia

Answer 100

**Arterial:** Inferior thyroid and internal thoracic arteries **Venous:** left brachiocephalic, internal thoracic and inferior thyroid veins **Lymphatic drainage:** parasternal, brachiocephalic and tracheobronchial lymph nodes **Innervation:** * Vagus

Answer 101

* variable location: ectopic and/or accessory thymic tissue may be located anywhere along the path of descent of the thymopharyngeal ducts. e.g. retrocaval, cervical, posterior mediastinal * variable shape: e.g. unilobed, trilobed, X-shaped, inverted V-shaped

Answer 102

The trachea is the primary trunk of the conductive airways **Function:** transmission of gas between the larynx and the main bronchi **Location:** Visceral space of the neck and posterior mediastinum

Answer 103

Made up of posteriorly incomplete cartilage rings with interspaced annular ligaments Enveloped by the trachealis muscle which is particularly prominent posteriorly Lined with ciliated epithelium Divided into: cervical and thoracic trachea **Origin:** continuation of the airway distal to the cricoid cartilage (C6) **Termination:** bifurcates at the carina level L4

Answer 104

**Arterial supply:** * Inferior thyroid arteries * Bronchial arteries **Venous drainage:** * Inferior thyroid veins * Azygos system **Lymphatics:** * Drainage into deep cervical, peri and para-tracheal nodes of the mediastinum **Innervation:** * Vagus and sympathetic trunk

Answer 105

* Posterior: oesophagus and recurrent laryngeal nerve * Anterior: Thyroid strap muscle, jugular notch, manubrium, great vessels of the superior mediastinum * Lateral: Sternocleidomastoid, brachiocephalic veins and arteries * Superior: larynx * Inferior: Sub-carinal lymph nodes, main bronchi

Answer 106

* Trachea oesophageal fistula * Tracheal atresia * Pig bronchus * Lunate trachea * Tracheal diverticulum

Answer 107

Branching tree of airways beginning at the carina. The lumen diameter decreases with each branching. Airways down to the level of the bronchioles contain c-shaped rings of hyaline cartilage to maintain the patency of the lumen. **Function:** transmission of gas between the trachea and the respiratory airways of the lungs

Answer 108

**Right side:** * Right main bronchus * Bronchus intermedius * Right Upper lobe bronchus * Right middle lobe bronchus * Right lower lobe bronchus **Left side:** * Left main bronchus * Left upper lobe bronchus * Left lower lobe bronchus **Further branches:** * Segmental bronchi * 20 to 25 generations of bronchioles * Terminal bronchioles

Answer 109

**Arterial supply:** * Bronchial arteries * Branches of the descending aorta **Venous drainage:** * Bronchial veins draining into the azygos system **Lymphatic drainage:** * Hilar nodes

Answer 110

* Bronchial cyst * Pig bronchus * Oesophageal branch * Azygos bronchus * Cardiac bronchus

Answer 111

Superior mediastinum is an artificially divided wedge-shaped compartment of the mediastinum located between the thoracic plane inferiorly and the thoracic inlet superiorly. The inferior mediastinum, comprising of the anterior, middle and posterior parts, lies inferiorly.

Answer 112

* superiorly: thoracic inlet * inferiorly: thoracic plane * laterally: mediastinal pleura * anteriorly: manubrium of the sternum * posteriorly: bodies of upper four thoracic vertebrae

Answer 113

**muscles:** origin of sternohyoid, sternothyroid and lower end of longus colli muscles **arteries:** aortic arch and great vessels **veins:** right and left brachiocephalic veins, left superior intercostal vein, upper half of superior vena cava **nerves:** phrenic, vagus and cardiac nerves; cardiac plexus; left recurrent laryngeal nerve lymph nodes: brachiocephalic; tracheobronchial; paratracheal **Organs:** * trachea * oesophagus * thoracic duct * thymus

Answer 114

The T5 level is also known as the transthoracic plane or plane of Ludwig. It is a horizontal plane at the level of the inferior endplate of L4. Divides the superior and inferior mediastinum

Answer 115

* Carina * Pulmonary trunk bifurcates * Thoracic duct crosses from right to left at this level * Azygos vein drains into the superior vena cava * Inferior concavity of the aortic arch * Ligamentum venosum * Termination of the pre-tracheal and pre-vertebral fascia * Cardiac plexus * Recurrent laryngeal loops under the arch * Superior vena cava * Sternal angle * Ribs 2 – 4 * Internal and external intercostal muscles * Internal thoracic artery * Lungs * Muscles of the thorax and arms * Humerus

Answer 116

The superior thoracic aperture is the superior opening into the thorax **Function:** Allow the passage of a large number of structure into and out of the thorax **Location:** Encircled by the first rib, the T1 vertebrae and the manubrium

Answer 117

* Lung apices * Trachea * Oesophagus * Thymus * Sometimes the thyroid

Answer 118

* Brachiocephalic veins * Internal thoracic arteries * Brachiocephalic truck * The left common carotid artery * The left subclavian artery **Lymphatics:** * Cervical lymph nodes * Thoracic duct

Answer 119

* Vagus nerves * Phrenic nerves * Ascending laryngeal nerves * The sympathethetic chain of ganglion

Answer 120

* Part of sternocleidomastoid * Sternohyoid * Sternothyroid

Answer 121

* Right common carotid and subclavian can pass through * Thyroid IMA artery can pass through * Thyroid can extend through * Cervical ribs

Answer 122

The intercostal spaces are the space between the ribs. There are 11 spaces on each side and they are numbered according to the rib which is the superior border of the space.

Answer 123

The intercostal spaces contain three layers of muscle: * External * Internal * Innermost The neurovascular bundle is found between the internal and innermost layers.

Answer 124

The external intercostal muscle fibres run down and medial The internal intercostal muscle fibres run down and lateral The deepest layer of muscle in the intercostal space is made up of three muscles which are collectively known as the tranversus thoracis group. This group includes the: * subcostal muscles posteriorly * the innermost intercostals laterally * the transversus thoracis / sternocostalis muscles anteriorly.

Answer 125

The neuromuscular bundles are found between the middle and innermost layers, protected by the costal groove of the superior rib of each intercostal space. They are ordered vein, artery, nerve from superior to inferior (mnemonic VAN). The collateral neurovascular bundle runs at the lower edge of the space, just above the inferior rib and the order is reversed, i.e. nerve, artery, vein from superior to inferior.

Answer 126

**Blood supply:** **Arterial supply:** Single large posterior intercostal artery and 2 smaller anterior intercostal arteries. In the first and second intercostal spaces a large posterior artery arises from the superior intercostal artery (a branch from the costocervical trunk). The arteries in the remaining spaces branch directly from the descending thoracic aorta. The anterior intercostal arteries arise from the internal thoracic and musculophrenic (below 6^th interspace). **Venous drainage:** Posterior veins drain into the azygos or hemiazygos veins. Anterior veins drain into the internal thoracic or musculophrenic veins. **Innervation:** Each intercostal space is supplied segmentally by muscular branches of anterior rami of spinal nerves T1-T11.

Thorax Flashcards

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