Cardiac blood vessels

Question 1

What is the interventricular sulcus?

Answer 1

The interventricular sulcus isa superficial groove or depression between the ventricles.

The anterior interventricular branch (LAD) of theleft coronary arteryruns in the sulcus along with the great cardiac vein.

Question 2

What are the septal defects?

Answer 2

Atrial Septal Defects:

• Usually due to incomplete closure of the foramen ovalis
• Causes enlargement of the right atrium and ventricle and dilation of the pulmonary trunk due to increased blood moving to the right side of the heart

Ventricular Septal Defects:

• Causes a left to right shunt of blood
• A largeVSD will increase pulmonary blood flow
• This causes severe pulmonary disease (hypertension, or increased blood pressure) because blood goes from the left ventricle to the right ventricle then to the lungs

Question 3

What is the internal anatomy of the right atrium?

Answer 3

Fossa ovalis: Adult remnant of foramen ovale

• Sinus venarum = smooth part
• Musculi pectinati/pectinate muscle = muscular ridges on inner wall of oracle
• Crista terminalis = smooth ridge of tissue
• Coronary sinus is present (drains cardiac veins into RA)

Question 4

What is the internal anatomy of the right ventricle?

Answer 4

• Trabeculae carneae: irregular muscular ridges on the wall of the ventricle
• Papillary muscles: conical muscles that attach to valve cusps to prevent prolapse. There are 3.
• Chordae tendineae: ‘heart strings.’ Fibrous cords that connect papillary muscles to cusps of valves
• Cusps of tricuspid valve
• Supraventricular crest: separates the ridged muscular wall of the inflow part of the chamber from the smooth wall of the conus arteriosus/infundulum (arise from bulbus cordis)
• Pulmonary Valve
• Supraventricular crest divides the trabecula carnae and infundulum
• Moderator band is only found in right ventricle

Overall:

• Inflow = trabeculae carnae
• Outflow = infundulum (smooth) – this leads to pulmonary trunk

Question 5

What is the internal anatomy of the left atrium?

Answer 5

• Smooth part (receives blood from 4 pulmonary veins)
• Musculi pectinati/pectinate muscle (smaller than that of RA)
• Crista terminalis

Question 6

What is the internal anatomy of the left ventricle?

Answer 6

Inflow:

• Trabeculae carnae
• 2 papillary muscles
• Chordae tendinae

Outflow (aortic vestibule):
-Smooth. Leads to aorta

Question 7

What is lub dub?

Answer 7

S1: closing of atrioventricular valves (lub)
S2: closing of semi lunar valves (dub)

Erb’s point is used to hear the dub (closing of semi lunar valve). Can be used for foreman ovale stuff

Question 8

What are the branches of the aorta?

Answer 8

1) Bracheocephalic trunk = right subclavian, right 2)common carotid
3) left common carotid
4) left subclavian

Other branches of aorta:
-Mediastinal and oesophageal branches

Question 9

What are the brachiocephalic veins?

Answer 9

Brachiocephalic veins are formed from the internal jugular vein and subclavian vein.

Brachiocephalic veins: drain blood from head, neck and upper limb to SVC.

Left brachiocephalic v. is 3 times longer than right.

Vagus nerve is between the internal jugular vein and the common carotid artery

Azygos vein: forms a collateral pathway between the SVC and IVC and drains blood from posterior walls of the thorax and abdomen. DRAINS INTO SVC

Question 10

What is the thoracic duct?

Answer 10

• Largest lymphatic channel in the body
• Conveys most of the lymph into the venous system
• Ascends in posterior mediastinum between the aorta and azygous v.

-Usually empties in to venous system via juction of
left internal jugular and subclavian vein (left venous angle)

Question 11

What is the right lymphatic duct?

Answer 11

Drains lymph from the few regions not drained by thoracic duct:

• The upper right section of the trunk
• right arm
• right side of the head and neck

Question 12

What are the nerves of the mediastinum?

Answer 12

• Oesophageal plexus: Vagal and sympathetic fibers (from sympathetic trunk) to smooth muscle and glands of inferior two thirds of esophagus
• Deep cardiac plexus (at T4/carina): parasympathetics and sympathetics, supplying the heart (between arch of aorta and carina)

Question 13

What is the Surgical Significance of the Transverse Pericardial Sinus?

Answer 13

A clamp or ligature places here can stop blood supply to these vessels. (ascending aorta and pulmonary trunk)

This is done in certain heart surgeries including coronary bypass

Question 14

Explain the azygous system

Answer 14

Thoracic walls drains to azygos vein

Right side:

• Supreme intercostal vein (1) drains to the right brachiocephalic vein
• Superior Intercostal vein (2,3 and 4) and posterior intercostal veins 5-11 drain into the azygos vein
• Azygos vein originates at the junction between the right ascending lumbar vein and subcostal vein. It enters the aortic hiatus at T12

Left side:

• Left ascending lumbar vein + left subcostal vein form the hemiazygos vein.
• Hemiazygos vein receives 9th-11th posterior intercostal veins. This enters azygos vein
• Left supreme intercostal vein (1) and superior intercostal veins (2,3,4) drain into the left brachiocephalic vein
• 5th-8th posterior intercostal veins drain into the accessory hemiazygos vein, which enters azygos vein.