Thorax

Question 1

what are the insertion sites of the diaphragm

Answer 1

anteriorly bounded by the xiphoid sternum(T8/T9) and costal margin

• laterally by the ends of ribs 11and 12
• posteriorly by the lumbar vertabrae of L1-L3 of the right and L1-L2 on the left

It is morphologically it is a derivative of the transversus layer of the body wall

Question 1

when do the IVC, oesophagus, and AA pass the diaphragm

Answer 1

T8- IVC

T10- Oesophagus+ vagus nerve

T12- Thoracic aorta(behind medial arcuate ligament) + thoracic duct + azygous + hemiazygous passes the crura of diaphragm

sympathetic trunk & least splachnic nerve pierces through diaphragm lateral to aortic hiatus

greater and lesser splachnic nerve pass through the crura

Question 2

what is the blood supply of the diaphragm

Answer 2

• above:
  1. pericardiacphrenic artery from internal thoracic artery
  2. musculophrenic artery from internal thoracic artery
  3. superior phrenic artery from thoracic artery
  4. lower 5 intercostal arteries and costal vessels(Main vessel)
• below
  1. inferior phrenic arteries from abdominal aorta(major supply)

venous supply
drain in brachiocephalic
2. azygous system
3. abdominal system- suprarenal system or IVC

Question 3

What is the lymphatic drainage of the Thorac/Abdomen

Answer 3

These lymphatic drainage follows the route of the veins, to the axillary and inguinal lymph nodes.
- Above the umbilicus, lymph from the bloody drain into the pectoral lymph node, back of the body to the scapular nodes.
- Below the umbilicus ant. aspect of the abdomen and perineum medial group of the superficial inguinal nodes. While lat and post. aspect of the abdomen to the lateral group

Question 4

What are the nerves supplying the thorax

Answer 4

Until the 2nd rib it is supplied by the supraclavicular branches of the cervical plexus.
- Afterwards they are supplied by the Anterior Cutaneous Branches of the spinal nerve from T2-L1
- Laterally there is a lateral cutaneous nerve of the intercostal nerve
- Posteriorly the skin is supplied by a posterior rami of spinal nerves (medial part supplies the superior part and lateral part supplies the inferior part)

Question 5

how do the myotomes of the trunk separate

Answer 5

They develop from the segmentation of the myotomes into dorsal and ventral parts, innervated by the dorsal and ventral nerves rami respectively

Question 6

what do the ventral and dorsal muscle groups develop into

Answer 6

Dorsal Muscles: Erector Spinae(innervated by the dorsal rami)
Ventral into 3 layers:(innervated by the ventral rami)
i.External intercostal; Serratus posteior
ii.Internal intercostal and internal oblique
iii.inner layer forms the transversus thoracis group (innermost intercostals, transversus thoracis and subcostals, and the diaphragm which migrates caudally. In the abdomen, Transversus abdomins, Quadratus Lumborum and lavator ani

Question 7

How is the thoracic cavity roofed?

Answer 7

It is roofed by the presence of the subprapleural membrane

Question 8

What causes the of presence of paravertebral gutters in the thorax

Answer 8

Presence of the spinal cord in the chest wall

Question 9

What causes the ridge on the angle of the ribs

Answer 9

It is formed by the attachment of the thoracolumbar fascia enclosing the erector spinae

Question 10

what costal cartilage make the costal margine

Answer 10

7th-10th costal cartilage

Question 11

What makes up the articular surfaces of the manubrium

Answer 11

The articular surfaces of the manubrium are covered in fibrocartiledge and will articulate with the ribs.

Question 12

What is the blood supply of the body of the sternum

Answer 12

From the internal thoracic artery

Question 13

What causes the digitations of the RIbs

Answer 13

The 1st digitations occur from the attachment of serratus anterior
i.1-8th Ribs
ii.the second digitations occur behind the origin of pectoralis minor
iii.External oblique from the last 8 ribs
iv. latissimus dorsi
v. Rectus abdominis on the anterior angle of the anterior surfaces of the 5th to 7th costal cartilage
vi. The costal cartilage contains the internal oblique
vii. Transverus abdominis and the diaphragm communicate with the internal surfaces of the lower 6 ribs
viii.Serratus Posterior communicate at the posteior angles of the subsequent ribs
ix. Scalen muscles
x. Quadratus lumborum
xi.iliocostalis and longissimus and levator costae

Question 14

What leads to the ossification of the ribs

Answer 14

Cartilage is laid down via the mesoderm on the 6th week of life and a bony centre forms on the 8th week at the angle of the rib but the head and tubercle ossify only around age 15

Question 15

Time period for ossification of the sternum

Answer 15

two longitudinal cartilaginous plates fuse in the midline and ossify on the 5th month, and fusion occurs from 15-25yrs xiphoid sternum ossify anytime after year 3

Question 16

What are the atypical ribs of and what make them unique

Answer 16

1st rib- single head with a single facet for synovial joint, and contains a radiate ligament to reinforce ant. part of the capsule. The cervical dome and apex of the lung hold these vessels and nerve( from medial to lat: cervicothoracic ganglion, supreme intercostal vein then artery and finally thoracic nerves)
2nd rib-
10th rib-no articular Facet with single head
11th rib- Single faces for the head and no articular facet
12th rib- single head for articulation with the 12th Vertebra. There are no tubercles, angle or costal groove

Question 17

What part of the ribs articulate with the vertebral column?

Answer 17

By their heads: joints of the head of the ribs superiorly head articulaters with the inferior articular surface of the vetebra and inferior head to the level of the vetebra
tubercles: via the costotransverse joints

Question 18

What are the 3 joints that stabalize the costotransverse joint

Answer 18

i.Lateral costotransverse ligament
ii.costotransverse ligament
iii.superior costotransverse ligament

Question 19

What are the layers of the intercostal muscles

Answer 19

i.External Intercostal Muscles/Posterior Serratus Muscles
ii.Internal Intercostal Muscles
iii. Subcostals, Innermost Intercostals, transversus thoracis
The neurovascular bundle lies in between iii. and ii.

Question 20

What are the origin and sites of insertion of the Posterior Serratus Superior Muscles

Answer 20

Origin: C6 &C7 and T1 & T2 supraspinous ligaments
Insertion: Angle of ribs 2-5

Question 21

What are the origin and sites of insertion for the Posterior serratus Inferior muscles

Answer 21

Origin: T11 and T12 supraspinous ligaments
Insertion: Aponeurosis which fuses with the posterior lamella of the lumbar fascia and lateral to the angles of the lowest 4 ribs

Question 22

What are the origin levator costae and its insertion and its nerve supply

Answer 22

Origin : Come in pairs near the tip of the transverse process
Insertion: at the upper border of the rib below, latersal
Nerve supply: POSTERIOR rami of C8-T11

Question 23

What is the course and the origin of the external costal muscles

Answer 23

Origin:Intercostal groove of the rib above
Insertion: Upper border of the rib below
it move obliquely inferior and forwards
Nerve Supply:

Question 24

What is the course and origin of the internal costal muscles

Answer 24

Origin:costal groove of the Insertion: fibres run upwards and backwards replaced posteriorly by the posterior intercostal membrane

Question 25

What 3 muscles consist the inner layer of the thorax

Answer 25

i.Subcostal muscles ii.Inner Intercostal muscles iii.Transversus Thoracis

Question 26

Run the course of in intercostal nerve

Answer 26

The Intercostal nerve comes from the anterior rami of the spinal nerve from the intercostal foramen into the neurovascular plane(between internal costal muscle and transversus thoracis). i. A collateral branch provides innervation for the muscles of the itnercostal space ii. A Lateral Cutaneous Branch that pierces at the mix-axillary line into an anterior and posterior branch iii.An anterior Cutaneous Branch and passes the chest in front of the internal thoracic artery and forms its terminal branch

Question 27

What is the drainage of the Intercostal veins

Answer 27

The intercostal veins drainage has 1 posterior- the lower 8th ribs drain into azygous on the right and hemiazygous and accesory azygous on the left. the blood of the the 2nd-4th ribs drain into a single trunk of superior intercostal vein. Left side then drains into L) brachiocephalic vein and the left into the azygous vein. Superficial to vagus but deep to phrenic. 2 anterior- anterior veins drain into the musculophrenic and internal thoracic veins however the first /supreme intercostal vein will drain into the vetebral vein/ brachiocephalic vein of it's own side.

Question 28

Where does the internal thoracic artery originate and its course and branches

Answer 28

The artery originates from the branch of subclavian artery and passes vertically down the sides of the border of the sternum below the 3rd rib it is surrounded by the venea comitantes draining into brachiocephalic vein. In each intercostal space it divides into the anterior intercostal arteries and there are also perforating branches in the intercostal space that also supply the breast. At the costal margin if further branches into i.Superior epigastric artery- passes between costal fibres of the diaphragm and the transversus abdominis ii.Musculophrenic artery- passess the costodiaghramic space and pierces the diaphragm on the 9th space and also branches into the- iii. Perciardiacophrenic branch which runs with the phrenic nerve

Question 29

What vessel supplies the first two spaces of the intercostal spaces

Answer 29

This is supplied by the superior intercostal artery from the descending branch of the costocervical trunk from the 2nd part of the subclavian artery behind scalenus anterior.

Question 30

What contents of the aortic opening and what level does this occur

Answer 30

Leve at T12 and contain the Aorta and the azygous vein and thoracic duct and cisterna chylii

Question 31

What is the contents of the easophageal opening and the level

Answer 31

Level at T10 and its contents include vagus trunk esophageal branches of the L) gastric artery, veins and lymphatics

Question 32

What is the contents of the Vena Caval opening

Answer 32

At Level 8 and it's contents also include the R) phrenic nerve

Question 33

What are the other structures that pass the diaphragm?

Answer 33

Left crus: Hemiazygous vein Greater, Lesser and Least splanchnic nerve sympathetic trunk L) phrenic nerve

Question 34

What is the nerve supply of the diaphragm

Answer 34

By the phrenic nerve(C4,C5,C6) and each half supplied by its respective nerve Lower intercostal nerve supplies the proprioceptive sensation

Question 35

At the angle of Luis, What contents pass through it

Answer 35

azygous vein joining the i.superior vena cava ii. bifucation of the trachea iii. Thoracic Duct iv. Ligamentum arteriosum + L) recurrent laryngeal nerve v.trecheobronchial lymph nodes vi. sup and deep lymph nodes

Question 36

What is the course of the Arch of Aorta

Answer 36

From the pericardium it goes towards T1/T2 and then passes backwards into the level T4, left of the midline. on the Left passed by the vagus and phrenic nerve. behind and infront of the lung root. between these 2 nerves contain the sympathetic plexus and vagus branches to make part of the cardiac plexus. The L) recurrent larygngeal nerve hooks AROUND the ligamentum arteriosum to go upwards

Question 37

What is the ligamentum arteriosum a remnant of and it's course

Answer 37

it is a fibrous remnant of the ductus arteriosus- a vessel that bypassed the lungs during development. It is formed at the commencement of the L) pulmonary trunk and is hooked by the L) recurrent laryngeal nerve around it. and the sup. part of the cardiac plexus anterior to th ligamentum arteriosum and deep part on it's right

Question 38

What are the confluences of the brachiocephalic veins and it's course

Answer 38

The brachiocephalic veins are a confluence of the Internal Jugular and Subclavian veins. In the neck it lies laterally to the common carotid artery. The subclavian lies lateral then in front of scalenus anterior. and there is joins to form the brachiocephalic vein, in front of the subclavian artery. it recieves vasculature from the thyrocervical veins, vertebral, inferior thyroid, internal thoracic and on the L) supr. intercostal. the right brachiocephalic vein starts behind the sternoclavicular joint and runs downwards the left brachiocephalic vein passess the sup. mediasternum on the above the arch of aorta, between the thymus and manubrial arch. - it also recieves the veterbral, internal thoracic, inf thyroid and superior intercostal vein and thymic bvein

Question 39

What vessels supply the trachea and its venous supply

Answer 39

The trachea is supplied by the thyroid and bronchial artery and drain via the the inferior thyroid vein

Question 39

What is made up of the cardiac plexus?

Answer 39

the cardiac plexus consist of the sympathetic(pain+tachycardia and dilatation), parasympathetic(bradycardia and constriction), afferent and small ganglia. and consists of a deep and superficial part. superficial- in FRONT of ligamentum arteriorus deep part- behind aortic arch but in front of the trachea

Question 40

Where does the phrenic nerve come from and its' course

Answer 40

The phrenic nerve comes from C4 in the neck over the anterior scalene muscles, the dome of the pleura of the lungs and lies in front of the vagus and the lung root. each side then have differenct courses. i.R) phrenic- Always have structures on it's medial side and it includes the brachiocephalic, sup. vena cava, the pericardium and the inferior vena cava. then pierces the central tendon WITH the Inferior vena cava ii. L) phrenic has L) common carotid and subclavian medially then passes OVER the L) superior intercostal vein AND crosses the vagus nerve and crossess laterally across the pericardium and L) ventricle and pierces the diaphragm independently on the L) side of the diaphragm.

Question 40

What is the course of the recurrent laryngeal nerve

Answer 40

COMPLEX answer as they have both wildly diffferent courses but both end on the right side the L) recurrent phrenic nerve hooks around the ligamentum arteriosum and exists in between the trachea and the esophagus the R) recurrent phrenic nerve hooks around the subclavian artery these nerves supply the larynx and oesophagus

Question 41

What is the vasculature of the epicardium

Answer 41

The drainage of the pericardium is via the internal thoracic artery via the pericardiophrenic and musculophrenic arteries and then drain into the azygos system

Question 42

what is the surfaces/borders of the heart?

Answer 42

1.Inferior Border- Right Ventricle and apex of the Left ventricle 2.Left borders- Left ventricle and the Left atrium 3.Right border- Right Atrium 4.anterior/sternocostal surface-Right Ventricle and right atrium on it's side the left ventricle on the left border, and the left auricle appendage 5.Diaphragmatic surface- R) ventricle 1/3 and 2/3 L) ventricle 6.Posterior surface- L) atrium

Question 43

what are the borders of the right atrium

Answer 43

the floor is almost completely filled up by the inferior vena cava. Medially the R) atrium is prolonged to the left by the R) auricle. The interatrial septum forms the posterior surface of the right atrium

Question 44

What are the cusps of the Tricuspid valve called

Answer 44

i.anterior ii.posterior iii.septal they receive chorda tendinae which are tendinous cords from papillary muscles and are named as the cords suggest

Question 45

What contains the pulmonary valve

Answer 45

three semilunar valve-attached at the infundibulum and commencement of the pulmonary trunk i.Left anterior ii.Right Anterior iiiPosterior

Question 46

What do the valves of the aorta contain?

Answer 46

The cusps of the aorta is cup shaped termed the aortic sinus. the three cusps are termed i. Right/posterior ii. Left/posterior-> L) coronary artery iii.Anterior-> R) coronary artery originated

Question 47

What is the course of the pulmonary artery

Answer 47

Initially the Pulmonary artery starts slightly higher than the aorta, it arches backwards intiially infront of the aorta then, to its left and under the concavity of the aortic arch and in front of the bronchus divides into the left and right main pulmonary artery

Question 48

What does the SA Node and AV node lie?

Answer 48

The SA node lie in the subepicardium of the right Atrial wall below the Superior vena cava, and the AV node lies in the right atrium on the interatrial septum above the septal cusp of the tricuspid to the left of the coronary sinus

Question 49

What is the course of the R) coronary artery

Answer 49

It comes form the anterior cusp, and then passess between the R) auricle and the infundibulum of the heart, it then runs downwards in the AV groove it turns around and runs posteriorly. It's branches are i.Conus Artery which supplies the infundibulum of the R) ventricle ii. SA nodal artery- passes back in between the aorta and right auricle, and forms a ring around the sup. vena cava. iii.Marginal artery- at the inferior border it forms this artery and moves to the left. iv.Posterior interventicular artery/desecending artery- lies on the diaphragmatic surface passing the interventricular groove. v. AV nodal artery- is an branch where IV comes from vi.Right posterolateral arteries

Question 50

What is the course of the L) coronary artery

Answer 50

Runs behind the pulmonary trunk from posterior sinus and emerges behind the L) auricle and infundibulum of the R) ventricle it then separates into it's terminal branches i.Circumflex artery- around the left margin of the back of the heart in the AV groove and may give off branches with the R) heart ii.Obtuse artery around the L) border of the heart iii.Anterior descending artery- lies in the interventricular groove and goes around the apex and also anastamoses iv. Conus branch v. Diagonal branch

Question 51

What is the drainage of the heart vessels

Answer 51

All the vessels drain into coronary sinus which is a vessel lying in the atrioventricular groove. covered with myocardium, and enters in the R) atrium. it consists of the i.great cardiac vein which follows anterior descending artery and enters into the L) end of the sinus ii.Middle cardiac vein following the posterior interventricular artery and opens near the termination of the coronary sinus iii.The small cardiac vein opens into the coronary sinus near its atrial end iv.The posterior vein of the left ventricle joins the sinus to the left of the middle cardiac vein v.small oblique vein of the left atrium runs downwards into the sinus near its left end. VI.anterior cardiac veins are a series of parallel veins that run across the surface of the right ventricle to open into the right atrium VII.The right marginal vein passes to the right along the inferior cardiac margin and joins the small cardiac vein, or drains directly into the right atrium in the manner of an anterior cardiac vein.

Question 52

What are the branches of the Thoracic Aorta

Answer 52

9 pairs of intercosta arteries 2 pairs of subcostal arteries Bronchial Artery esophageal vessels pericardial and phenic vessels

Question 53

What are the course of the esophagus?

Answer 53

Starts at the level of C6, passes the diaphragm at T10 and into the stomach at T11. The cervical portion starts at T5 in front of the paravetebral fascia, in the midline then goes to the left and then goes back to midline at T7 and then goes in fron of the thoracic aorta. in the superior mediasternum, the arch of aorta and vena cava/azygos on the right and the trachea is anterior to this, however at the birfucation is crossed by the main left bronchus anteriorly+Right pulmonary artery. in the posterior mediasternum

Question 54

What are the blood vessels supplying the esophagus

Answer 54

Inferior thyroid artery from thyrocervical branches Esophageal branches Bronchial arteries inferiorly by the left gastric artery Venous return via superior- Brachocephalic veins Middle- Azygos vein inferior- L) gastric vein

Question 55

What is the structure of the esophagus

Answer 55

The esophagus consists of 2 layers - i.Inner Circular muscle ii.Outer longitudinal muscles Upper esophagus is skeletal and lower is smooth 2 bands are formed in inferior constrictor of the pharynx and the other

Question 56

What forms the azygos vein

Answer 56

Union of the ascending lumbar vein and the subcostal vein, in enters the thorax via the right crus with the lateral to the thoracic duct. posterior to the esophagus. It also receives the lower 8 posterior intercostal veins. The bronchial veins, and esophagus veins from the middle vein. The two hemiazygous veins join in T7,T8

Question 57

What are the hemiazygous vein

Answer 57

They receive the LEFT lower eight intercostal veins and are formed by the union of the ascending lumbar veins and subcostal vein(which communicates with the left renal vein) and moves pass the left crus and also drains vessels in the lower esophagus

Question 58

What are the surfaces of the mediasternum?

Answer 58

on the left there is a cardiac notch, with a pericardium that ends up leaving a deep mark, the arch and the aorta, the subclavian vessels and the esophagus also make a mark.